Terry Yager
Veteran Member
Gotta agree with ya on the TEAC drives, I use nothing but most of the time (although my K-II is the glaring exception, I like to keep her pure).
--T
--T
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Kaypro II drive problem
- Thread starter tezza
- Start date
chuckcmagee
Veteran Member
I finally managed to test all the real old Tandon single sided drives I own. Out of 3 drives, all 3 controller cards have various issues, mostly with improper control of the head stepper motor. When I get more time, I will do the "take controller card from working newer drive" and see if the bottom stepper motor parts actually do work. I suspect that all 3 of the bottom parts will work.
Oh ya, I do have few Kaypros. Will have to see if any have a working single sided Tandon drive in them.
Oh ya, I do have few Kaypros. Will have to see if any have a working single sided Tandon drive in them.
Chuck(G)
25k Member
I have at least three different versions of TM-100 drive electronics PCBs--some for 6-wire steppers, some for 3-wire and at least one for a 4-wire stepper. Be careful when you start swapping.
chuckcmagee
Veteran Member
Oooooo, thank you, thank you, bow! I was freely moving my 3 controller cards around, watching how the stepper reacted with each one. I got lucky. Turns out all three drives all use 6 wire stepper layout. I'll be sure to look very carefully at any Kaypro drives I might find.
And yes, 3 controllers and 3 drives = 9 different combinations. Took me almost the entire day moving controller cards around and getting my flashlight out to watch the head movement. No wonder my Northstar Horizon would never boot!
And yes, 3 controllers and 3 drives = 9 different combinations. Took me almost the entire day moving controller cards around and getting my flashlight out to watch the head movement. No wonder my Northstar Horizon would never boot!
tezza
Veteran Member
Yea, whatever drive I use as a replacement will have to be full height, so not to spoil the visual appearence of the machine.
I have a full height TEAC drive which I use for the System 80. It was originally an Apple drive, but I modified it (or should I say re-modified it back to the factory original) so it would work on any standard machine. I tried fitting this in the Kaypro case but unfortunately the position of the card edge is in a different position (and is the other way up) from the Tandon, and the disk drive cable could not be twisted/stretched enough to fit it.
Tez
Dwight Elvey
Veteran Member
Hi
Although, I mentioned this before, I thought I'd mention this again.
With the belt drives, the surface of the flywheel must be absolutely
smooth. Not just to the eye but truly smooth. Slight problems
there will also cause problems with the inner tracks.
On the older drives, I've even gone so far as to mount the drive
on a lath and smooth the flywheel down.
Most of these drives have pot metal flywheels that can form irregular
oxides on the surface. I'd still recommend taking some fine sand paper
( 600 or finer ) and spin the flywheel on it until one a saw shiny metal
surface.
Dwight
GADFRAN
Experienced Member
More of my "2 cents" if interested
More of my "2 cents" if interested
Thursday, January 01, 2009
Tezza,
Wow all of these posts so fast! You and your topic are sure popular.
Some further thoughts on my posting and the others about your “new” Kaypro and disk drive issues.
My original post was just a “quickie” to help you out ASAP, so you did not waste too much time and get into too much frustration, even though as a hobby, it can be a lot of fun – “a labor of love” as so many have said.
So glad you finally got one! We had emailed each other a few times in the past.
Things look like they are working out for you, but you and others may have future disk drive and other issues develop, so I offer the following.
We can PM each other if more details are needed, since this post is already so long.
If anyone is interested, continue reading. If not, just move on.
========================================================
With vintage computers, as in so many other areas, there are many unknowns and possible unintentional consequences.
So please note that if you decide to make use of any of the information I provide, including in this and any other postings, in addition to my web site, then you use it
“only and completely at your own risk.”
All this is offered in “good faith” and I can have no liability in any form and any way, including many of the other standard disclaimers. It is the best I know at the present time from the information I have. If you cannot accept this, then do not use this information.
Also note, that many beginners may not be aware of the possibility of harmful and even lethal electrical hazards with your computer activities, especially when you open your computer case. There can be other hazards also, so be careful and get sufficiently informed.
You may even want to hire an appropriate and qualified professional in such matters.
========================================================
Erik, as the webmaster, if any of this is not appropriate just delete, move, etc. any and all of it as you see fit. I do not want to clutter up the site unnecessarily.
An idea – another section on your web site like an “Archive” for such longer and more detailed posts? By the way, love how you keep upgrading the site – many thanks from all of us!
========================================================
I will eventually post such things as this on my web site, but this is quicker. I use an outside web service and it takes awhile to update the site and there is some expense involved.
Also, this thread may become very useful for others who have similar Kaypro drive & other issues. In addition, some may have their drives work fine after a fix and then other issues develop.
This thread may also help to reduce the number of inquiries and responses on some of the same questions some new Kaypro owners continue to have.
Some specific details -
1] If you want to be a “purist,” then you probably will stick with the Tandons. But for those who want to actually use their Kaypro systems a lot, then the Teacs are something to consider in order to not have to do so many repairs. After all, the real fun is using your Kaypros and not just looking at them.
2] I spent a great deal of time learning and repairing the Tandons, also using the Dyson and other diagnostic / alignment systems, etc., until the eventual upgrades and the 4 Teacs per system. I can just say that the responses you got all seem accurate from my experiences, as far as I can tell, but my memory may not be as sharp as from way back then.
3] I agree, the Tandons were not bad drives for their time, but time moves on and better options become available.
4] Naturally, there will always be conflicts of actual experiences for many reasons [“the law of unintentional, and many times unknown, consequences”].
5] Consequently, I have a collection of about 40 – 50 in our basement in all sorts of condition [great to just for parts!], but they are old and not professionally refurbished. So “new” – really professionally refurbished [I do not think you can get “real new” or “not used” any more] would be the best bet to save you a lot of frustration, time and effort. Also see below for some additional issues.
6] Tandons are still available at reasonable prices from Farris [see my post] and other posts on this web site. The 5.25” floppies are also available. You may want to try newer floppies, since I have seen some reports of the media breaking down with older and used floppies of that early era.
7] Who thought that around 25 years later these systems and floppies would still be in use!
8] Many reference documents may already be available as scanned downloads elsewhere. I know the Kaypro service manuals are available from a group in Britain. Erik knows about them.
9] A] Some may know a lot of this, but from my experience with this so excellent web site so far and with vintage computing in general, many probably do not.
B] So much to learn and so little time!
C] Where can you go to get such great technical information so quickly from so many people worldwide and over the holidays yet! This web site is similar to our local computer group - Lehigh Valley Computer Group.
========================================================
10] As most long time Kaypro users know, the main issues with the Kaypros were the soldering on the power supplies and the Tandon drives. Otherwise, what great machines!
11] The soldering issue was rather simple to manage. Just remelt the main solder areas on the power supplies, especially for the connectors to other areas of the Kaypro. Micro Cornucopia indicated to me that this was about 90% of all the Kaypro issues that they dealt with at that time.
12] A] I cannot begin to tell you how hard my wife and I used our 6 Kaypros for almost 10 years in so many projects. Once I learned how to do my own work on them, I rarely had any issues after the upgrades to Kaypro “8” ‘ s stabilized and I was using new half height Teac drives. Heat was the main issue, since we were pushing the system well beyond what it was designed for. More details below.
B] With the Teac drives, when I started up all 6 Kaypro “8” ‘s last year at about this time to check them out, they all immediately came up, but naturally some a little slower than others, they read the disks in the drives and ran the software – after between 10 – 15 years in storage and not being used!
13] A] Some may not be aware that with only 64 K in RAM, there was a lot of swapping going on with the A drive for the software and even for the B drive, where you stored the files you were making. Thus, the A drive was usually the first to show issues. This sounds like what you found Tezza. You know computers well and knew the “swap” of the B drive for the A drive should be tried and it worked.
B] When I was doing big projects like extensive spreadsheets, the disk drives would continuously spin for 15 to 30 minutes swapping and / or storing data!!! What a workout! So while that was taking place, I worked on another project with a second Kaypro setup right next to the first Kaypro.
14] Another important aspect, especially with respect to future issues that may develop with a Kaypro, there are many variations of even the same model due to possible last minute undocumented production changes [no ISO 9000 then] while they were built. Kaypro got pretty chaotic and hectic at times and some models may contain items that are not contained in other units of that same model due to many reasons [e.g., use up spare parts, run out of certain parts, errors, etc.]. Quality control / assurance [QC/QA] must have been a nightmare then. More details below.
15] A] But Careful inspection of your particular Kaypro may speak volumes, if you know what to look for. We can all help each other in this regard.
B] Unless you know about many of these details on just what specific Kaypro model and version you have, along with any modifications that may have been made, then it will be very difficult to try to effectively and efficiently deal with any future issues that may develop.
C] By the way, how did you get it, or maybe you cannot tell us [a midnight requisition? – but knowing you, I don’t think you are into that!]. Do you know any details of its past history that could provide some clues for this and other issues that may develop in the future?
16] A] 1] First a picture “speaks a 1000 words” – thanks for providing one - your drives are mounted vertical, rather than the more common horizontal. Looks like there is no drive shield also. Also drives mounted with bottom of drives towards CRT and power supply, which can protect their circuit boards and circuits better from any electrical interference.
2] USA FCC hammered TRS-80’s in this regard and all had to be
eventually recalled. Apple also had this issue and they were able to economically manage it eventually. So it can be an important but variable issue.
B] 1] Front configuration of other items – LED and knob [brightness control ? – but usually on the back panel] are different – at top and not down side of CRT – was this series made for just New Zealand? You said TRS-80’s were different in your country than in the USA and were called “Dick Smith System 80’s”.
2] I found some Kaypros have a Netherlands address on the back. I
have one and so does Erik. But otherwise they seem the same.
C] These are all “tip offs” that your Kaypro may be different from many standard others. Did someone do some modifications? This may not be important now, since you seem to have your disk drives presently under control, but may become significant when future issues develop.
D] More pictures can help, especially of the cover, back panel and close up of main board. Also, what is the serial number [S/N] on the back panel?
E] Compare your Kaypro to the many pictures of my Kaypros on my web site under the folder “Special” – I did a 2008 calendar with many such pictures. Check the main board chip layout and chip numbers and socket “U” numbers especially. But keep in mind that they were modified in certain areas to Kaypro “8” ‘s however. I can provide more details, if needed.
F] I put these pictures and draft of my book on my web site since we still do not have DSL / broadband in our very rural area yet. Such big MB downloads can take from ½ to over an hour to upload or download.
17] A] Looks like you are taking the drives out to check how they perform while you make adjustments. Sometimes when you put them back into the computer, they do not work – can be a sign of interference from the rest of the computer, among many other issues.
B] You may also want to put the cover back on before you test to see if the drives are working after you fix them. With all the electronic stuff we have in our homes today, some may cause some interference. I had some even back in the 1990’s. Kaypro was smart using a heavy duty aluminum metal case for many reasons!
18] A] Looks like your main board has chips at U43 and U47 with the usual white stickers on them. They can be a key as to what particular Kaypro you really have.
B] Sharkonwheels on this web site will know a lot more – Shark if you are reading this, correct me if I made any errors. I am sure you will help Tezza and other people, since that is just the kind of guy you are.
C] If U47 Monitor ROM has a white sticker on it indicating 81-232, then you have a Kaypro 4 “at heart”, even though the outside case says you have a Kaypro II [note not “2” – that can be another issue]. If you can locate a Micro Cornucopia Pro-8 chip, then you can change and add different drives at will, if you ever want to upgrade.
D] Note U43 Character ROM can be another different issue.
E] 1] Shark and others may even be able to “make” such chips for you, although there may be legal and other issues involved and he will certainly need to be compensated in some substantial way for such specialized services.
F] If U47 is 81-149 [possibly a “C” after it also, an “A” or a “B” version has some history of issues surrounding them] then you have a Kaypro II.
G] If it is 81-292-A, then you have a Kaypro 4, but a 1984 year
version. This may be able to be upgraded to 4 disk drives using the currently still available Advent system. Check with Sharkonwheels on this web site – he is an expert on the 1984 Kaypros – I am more into the 1983’s.
19] A] Note also the main board designation for the year 1983’s is 81-240, 81-184 or 81-110 {obsolete – but I have one I believe} [may be on back of board on lower right side when look at top of board].
B] If the board number is 81-184, it is a 1984 year computer.
C] Note some of these boards and or U47 chips can use different versions of CP / M.
D] Note also that there are a variety of Kaypro “ 2 ’ s ” - 2X, 2/84, New 2, etc.
E] Kaypro “ II “ is usually for the 1983 year computers.
F] There are many Kaypro 4 versions. There is even a Kaypro “1” used as a prototype only, if you ever wondered about that number designation. One of the later Kaypro “2” ‘ s was actually a “II “ and produced using a lot of old spare parts, just to get some much needed funds as they approached bankruptcy probably . Osborne apparently did this also. Many others probably did and still do.
G] There is much confusion about all these designations, chips, main boards, CP / M’s, etc., so be careful.
H] I have gotten many inquiries and it is difficult for some to accept that it was just that way in early computing. Another motivation for this long document is to help others who are in such a situation – it can help keep down the traffic in responding about the same issue over and over again. They can just go to this posting for the info.
I] But today, we have some similarities – Win 95, Win 98, Win ME, Win XP, Vista, etc. and now the new Windows 7 is coming – all leading to many compatibility issues.
J] Naturally, if you do not have the right CP / M versions, then even if your disk drives are ok, you cannot boot! Be grateful you have the right boot disk [many do not] and that it works with your Kaypro.
20] A] 1] A Micro Cornucopia article noted that the floppy disk controller [FDC1793, at socket U82] and / or the data separator [FDC 9216, at socket U88] can be issues. Some of these may still be available at JDR Electronics in California.
2] But beware of export restrictions! Will you get a knock on the door
by home security? Probably not, but ……….- who needs the grief!
3] Also there may be some custom duties. There are some posts on
www.classiccmp.org email distribution that some shippers will back charge the person who shipped the items for any such duties, if they are not paid by the recipient.
B] 1] a] JDR also still has many of the other Kaypro main board chips, including the Z80’s – CPU, PIO and SIO very cheaply [less than $1 each, even just $0.25], since they were and I guess still are, so commonly used.
b] Also check the versions of these Z80 chips you have –
Z80A, Z80B, etc. These are faster chips and may generate excess heat, which can show up after you have run your computer for a few hours. Then the “fun” begins – lockups, shutdowns, disk drive issues and other erratic behavior.
2] If you have a “real “1983 Kaypro II and they are A’s or B’s, then
someone may have done some upgrades on your Kaypro. They should just be Z80’s with no other letters added. Other Kaypro versions / models may have the “letter” designated versions – up to eventually “H” I believe.
C] Apparently, Kaypro got a big batch of bad data separators that caused a lot of long term issues.
D] In fact, I published a short note in Micro Cornucopia in 1987 on two of my upgraded Kaypros that eventually failed because of these 1793 chips, probably due to the heat issues involved with stressing the basic design of the system with these upgrades. It was one of my similar short publications to help others from my experiences.
E] 1] These Micro Cornucopia [MC] upgrades were just great, with very complete and understandable directions and quality parts, but you were really pushing the system way beyond what they were originally designed for, so there were some “break-in” issues that developed.
2] One was this heat generation, so if you have an upgraded Kaypro,
be aware of this. Comically, it was discovered when we put the tops back on our Kaypros. The people designing the upgrades never did this, since they were always “tinkering” with their systems. That is why I added a fan and even a perforated aluminum top to help cool them. Then all was fine.
E] One MC article even recommends just replacing the Tandons with half height good quality Japanese drives. It is easy and quite inexpensive. But I may note that there are some other considerations – setting the jumpers correctly, twisting the drive cables correctly, etc. But overall, no big deal if you are aware of these issues.
21] A] One of the best source of Kaypro technical information are the Micro Cornucopia journals of course. If they could be scanned and made available, it would be a great service.
B] Unfortunately, in our continuing downsizing in retirement, many years ago I could never have imagined I would ever need these journals again. We had moved on to Gateways, Compaqs, Gateways, Toshibas, etc. So they were tossed into the dumpster, along with much else from that era.
C] I do have some of the main articles, but they are marked up with my notes. In addition, it would be a big scanning job to do. Then there are the legal issues and how best to make them available and archived at a central location. Many are struggling with such issues for many computers today. Hopefully they will be eventually resolved in a satisfactory manner.
22] A] Also, another consideration of that era is the concept of “hypergrowth” that Osborne coined and is the title of his book on his company. I bring out some of this in the draft of my book on that era – “a computer built every 5 minutes!”.
B] For perspective, Tandon was selling “28,000 disk drives a month” to Kaypro alone! So right there you have a great potential for at least some bad drives getting into the system. Did you get one and others did not?
C] So some may be disappointed with some “issues” they may face with their Kaypros and other vintage computers, but for perspective, it is a miracle that so many were made so well and still work today from that early and so new era of computing!
D] I can say that all the Kaypros we got, 2 were new, and the 4 others used, were and still are incredible working machines. So rugged and so well designed and made. Again, like the Tucker cars of the 1940’s. But things change and life moves on, but what could have been if they could have continued profitably?
========================================================
So that is it for now. Hope some of this is of some interest and use.
I encourage all to please return the favor and continue to offer your input so we can all benefit.
If there is enough interest, then a lot of this Kaypro stuff can be pursued more intensively and even put on my web site. But right now, my information indicates that we are a very small group, so we will just have to try to do the best we can.
With the present global economy situation, it may take several years before we all get back to a time when we have more disposable income to devote to our hobby and to more substantially preserving these vintage computers.
All the best for 2009 and thanks for your interest and keeping those Kaypros and other vintage computers running!
Frank
Some additional background info if you are interested –
Please keep in mind, I am not a computer “techie!” I learned on my own what I had to learn to keep our systems going – we had a big investment in so many ways to try to protect and extend the usefulness of their lives, until we eventually went to more modern windows systems.
Also, my research for the draft of my book on these early portable, personal computers [PPC’s] – Osborne, Kaypro, Compaq, IBM, etc.] provided much additional information.
The draft is available as a free download on my website under the folder “Special,” if you are interested. Two publishers are now reviewing it for possible publication. But with the global economy as it is, I doubt either will be able to publish it. So I will eventually publish it on my own using our computer and inexpensive laser black and white printer. Any funds from such a publication will just go to fund my continuing STS research, which of course, includes vintage computers.
Please note that some of the files on this website, including this draft, got corrupted recently and when downloaded, appeared to be just simple text that was not very sophisticated and understandable. If this happens again, just let me know and I will have the web site provider fix it again.
Also, please ignore any “typos,” since I already spent a lot of time on this. But my wife is an English major and has very high standards!
More of my "2 cents" if interested
Thursday, January 01, 2009
Tezza,
Wow all of these posts so fast! You and your topic are sure popular.
Some further thoughts on my posting and the others about your “new” Kaypro and disk drive issues.
My original post was just a “quickie” to help you out ASAP, so you did not waste too much time and get into too much frustration, even though as a hobby, it can be a lot of fun – “a labor of love” as so many have said.
So glad you finally got one! We had emailed each other a few times in the past.
Things look like they are working out for you, but you and others may have future disk drive and other issues develop, so I offer the following.
We can PM each other if more details are needed, since this post is already so long.
If anyone is interested, continue reading. If not, just move on.
========================================================
With vintage computers, as in so many other areas, there are many unknowns and possible unintentional consequences.
So please note that if you decide to make use of any of the information I provide, including in this and any other postings, in addition to my web site, then you use it
“only and completely at your own risk.”
All this is offered in “good faith” and I can have no liability in any form and any way, including many of the other standard disclaimers. It is the best I know at the present time from the information I have. If you cannot accept this, then do not use this information.
Also note, that many beginners may not be aware of the possibility of harmful and even lethal electrical hazards with your computer activities, especially when you open your computer case. There can be other hazards also, so be careful and get sufficiently informed.
You may even want to hire an appropriate and qualified professional in such matters.
========================================================
Erik, as the webmaster, if any of this is not appropriate just delete, move, etc. any and all of it as you see fit. I do not want to clutter up the site unnecessarily.
An idea – another section on your web site like an “Archive” for such longer and more detailed posts? By the way, love how you keep upgrading the site – many thanks from all of us!
========================================================
I will eventually post such things as this on my web site, but this is quicker. I use an outside web service and it takes awhile to update the site and there is some expense involved.
Also, this thread may become very useful for others who have similar Kaypro drive & other issues. In addition, some may have their drives work fine after a fix and then other issues develop.
This thread may also help to reduce the number of inquiries and responses on some of the same questions some new Kaypro owners continue to have.
Some specific details -
1] If you want to be a “purist,” then you probably will stick with the Tandons. But for those who want to actually use their Kaypro systems a lot, then the Teacs are something to consider in order to not have to do so many repairs. After all, the real fun is using your Kaypros and not just looking at them.
2] I spent a great deal of time learning and repairing the Tandons, also using the Dyson and other diagnostic / alignment systems, etc., until the eventual upgrades and the 4 Teacs per system. I can just say that the responses you got all seem accurate from my experiences, as far as I can tell, but my memory may not be as sharp as from way back then.
3] I agree, the Tandons were not bad drives for their time, but time moves on and better options become available.
4] Naturally, there will always be conflicts of actual experiences for many reasons [“the law of unintentional, and many times unknown, consequences”].
5] Consequently, I have a collection of about 40 – 50 in our basement in all sorts of condition [great to just for parts!], but they are old and not professionally refurbished. So “new” – really professionally refurbished [I do not think you can get “real new” or “not used” any more] would be the best bet to save you a lot of frustration, time and effort. Also see below for some additional issues.
6] Tandons are still available at reasonable prices from Farris [see my post] and other posts on this web site. The 5.25” floppies are also available. You may want to try newer floppies, since I have seen some reports of the media breaking down with older and used floppies of that early era.
7] Who thought that around 25 years later these systems and floppies would still be in use!
8] Many reference documents may already be available as scanned downloads elsewhere. I know the Kaypro service manuals are available from a group in Britain. Erik knows about them.
9] A] Some may know a lot of this, but from my experience with this so excellent web site so far and with vintage computing in general, many probably do not.
B] So much to learn and so little time!
C] Where can you go to get such great technical information so quickly from so many people worldwide and over the holidays yet! This web site is similar to our local computer group - Lehigh Valley Computer Group.
========================================================
10] As most long time Kaypro users know, the main issues with the Kaypros were the soldering on the power supplies and the Tandon drives. Otherwise, what great machines!
11] The soldering issue was rather simple to manage. Just remelt the main solder areas on the power supplies, especially for the connectors to other areas of the Kaypro. Micro Cornucopia indicated to me that this was about 90% of all the Kaypro issues that they dealt with at that time.
12] A] I cannot begin to tell you how hard my wife and I used our 6 Kaypros for almost 10 years in so many projects. Once I learned how to do my own work on them, I rarely had any issues after the upgrades to Kaypro “8” ‘ s stabilized and I was using new half height Teac drives. Heat was the main issue, since we were pushing the system well beyond what it was designed for. More details below.
B] With the Teac drives, when I started up all 6 Kaypro “8” ‘s last year at about this time to check them out, they all immediately came up, but naturally some a little slower than others, they read the disks in the drives and ran the software – after between 10 – 15 years in storage and not being used!
13] A] Some may not be aware that with only 64 K in RAM, there was a lot of swapping going on with the A drive for the software and even for the B drive, where you stored the files you were making. Thus, the A drive was usually the first to show issues. This sounds like what you found Tezza. You know computers well and knew the “swap” of the B drive for the A drive should be tried and it worked.
B] When I was doing big projects like extensive spreadsheets, the disk drives would continuously spin for 15 to 30 minutes swapping and / or storing data!!! What a workout! So while that was taking place, I worked on another project with a second Kaypro setup right next to the first Kaypro.
14] Another important aspect, especially with respect to future issues that may develop with a Kaypro, there are many variations of even the same model due to possible last minute undocumented production changes [no ISO 9000 then] while they were built. Kaypro got pretty chaotic and hectic at times and some models may contain items that are not contained in other units of that same model due to many reasons [e.g., use up spare parts, run out of certain parts, errors, etc.]. Quality control / assurance [QC/QA] must have been a nightmare then. More details below.
15] A] But Careful inspection of your particular Kaypro may speak volumes, if you know what to look for. We can all help each other in this regard.
B] Unless you know about many of these details on just what specific Kaypro model and version you have, along with any modifications that may have been made, then it will be very difficult to try to effectively and efficiently deal with any future issues that may develop.
C] By the way, how did you get it, or maybe you cannot tell us [a midnight requisition? – but knowing you, I don’t think you are into that!]. Do you know any details of its past history that could provide some clues for this and other issues that may develop in the future?
16] A] 1] First a picture “speaks a 1000 words” – thanks for providing one - your drives are mounted vertical, rather than the more common horizontal. Looks like there is no drive shield also. Also drives mounted with bottom of drives towards CRT and power supply, which can protect their circuit boards and circuits better from any electrical interference.
2] USA FCC hammered TRS-80’s in this regard and all had to be
eventually recalled. Apple also had this issue and they were able to economically manage it eventually. So it can be an important but variable issue.
B] 1] Front configuration of other items – LED and knob [brightness control ? – but usually on the back panel] are different – at top and not down side of CRT – was this series made for just New Zealand? You said TRS-80’s were different in your country than in the USA and were called “Dick Smith System 80’s”.
2] I found some Kaypros have a Netherlands address on the back. I
have one and so does Erik. But otherwise they seem the same.
C] These are all “tip offs” that your Kaypro may be different from many standard others. Did someone do some modifications? This may not be important now, since you seem to have your disk drives presently under control, but may become significant when future issues develop.
D] More pictures can help, especially of the cover, back panel and close up of main board. Also, what is the serial number [S/N] on the back panel?
E] Compare your Kaypro to the many pictures of my Kaypros on my web site under the folder “Special” – I did a 2008 calendar with many such pictures. Check the main board chip layout and chip numbers and socket “U” numbers especially. But keep in mind that they were modified in certain areas to Kaypro “8” ‘s however. I can provide more details, if needed.
F] I put these pictures and draft of my book on my web site since we still do not have DSL / broadband in our very rural area yet. Such big MB downloads can take from ½ to over an hour to upload or download.
17] A] Looks like you are taking the drives out to check how they perform while you make adjustments. Sometimes when you put them back into the computer, they do not work – can be a sign of interference from the rest of the computer, among many other issues.
B] You may also want to put the cover back on before you test to see if the drives are working after you fix them. With all the electronic stuff we have in our homes today, some may cause some interference. I had some even back in the 1990’s. Kaypro was smart using a heavy duty aluminum metal case for many reasons!
18] A] Looks like your main board has chips at U43 and U47 with the usual white stickers on them. They can be a key as to what particular Kaypro you really have.
B] Sharkonwheels on this web site will know a lot more – Shark if you are reading this, correct me if I made any errors. I am sure you will help Tezza and other people, since that is just the kind of guy you are.
C] If U47 Monitor ROM has a white sticker on it indicating 81-232, then you have a Kaypro 4 “at heart”, even though the outside case says you have a Kaypro II [note not “2” – that can be another issue]. If you can locate a Micro Cornucopia Pro-8 chip, then you can change and add different drives at will, if you ever want to upgrade.
D] Note U43 Character ROM can be another different issue.
E] 1] Shark and others may even be able to “make” such chips for you, although there may be legal and other issues involved and he will certainly need to be compensated in some substantial way for such specialized services.
F] If U47 is 81-149 [possibly a “C” after it also, an “A” or a “B” version has some history of issues surrounding them] then you have a Kaypro II.
G] If it is 81-292-A, then you have a Kaypro 4, but a 1984 year
version. This may be able to be upgraded to 4 disk drives using the currently still available Advent system. Check with Sharkonwheels on this web site – he is an expert on the 1984 Kaypros – I am more into the 1983’s.
19] A] Note also the main board designation for the year 1983’s is 81-240, 81-184 or 81-110 {obsolete – but I have one I believe} [may be on back of board on lower right side when look at top of board].
B] If the board number is 81-184, it is a 1984 year computer.
C] Note some of these boards and or U47 chips can use different versions of CP / M.
D] Note also that there are a variety of Kaypro “ 2 ’ s ” - 2X, 2/84, New 2, etc.
E] Kaypro “ II “ is usually for the 1983 year computers.
F] There are many Kaypro 4 versions. There is even a Kaypro “1” used as a prototype only, if you ever wondered about that number designation. One of the later Kaypro “2” ‘ s was actually a “II “ and produced using a lot of old spare parts, just to get some much needed funds as they approached bankruptcy probably . Osborne apparently did this also. Many others probably did and still do.
G] There is much confusion about all these designations, chips, main boards, CP / M’s, etc., so be careful.
H] I have gotten many inquiries and it is difficult for some to accept that it was just that way in early computing. Another motivation for this long document is to help others who are in such a situation – it can help keep down the traffic in responding about the same issue over and over again. They can just go to this posting for the info.
I] But today, we have some similarities – Win 95, Win 98, Win ME, Win XP, Vista, etc. and now the new Windows 7 is coming – all leading to many compatibility issues.
J] Naturally, if you do not have the right CP / M versions, then even if your disk drives are ok, you cannot boot! Be grateful you have the right boot disk [many do not] and that it works with your Kaypro.
20] A] 1] A Micro Cornucopia article noted that the floppy disk controller [FDC1793, at socket U82] and / or the data separator [FDC 9216, at socket U88] can be issues. Some of these may still be available at JDR Electronics in California.
2] But beware of export restrictions! Will you get a knock on the door
by home security? Probably not, but ……….- who needs the grief!
3] Also there may be some custom duties. There are some posts on
www.classiccmp.org email distribution that some shippers will back charge the person who shipped the items for any such duties, if they are not paid by the recipient.
B] 1] a] JDR also still has many of the other Kaypro main board chips, including the Z80’s – CPU, PIO and SIO very cheaply [less than $1 each, even just $0.25], since they were and I guess still are, so commonly used.
b] Also check the versions of these Z80 chips you have –
Z80A, Z80B, etc. These are faster chips and may generate excess heat, which can show up after you have run your computer for a few hours. Then the “fun” begins – lockups, shutdowns, disk drive issues and other erratic behavior.
2] If you have a “real “1983 Kaypro II and they are A’s or B’s, then
someone may have done some upgrades on your Kaypro. They should just be Z80’s with no other letters added. Other Kaypro versions / models may have the “letter” designated versions – up to eventually “H” I believe.
C] Apparently, Kaypro got a big batch of bad data separators that caused a lot of long term issues.
D] In fact, I published a short note in Micro Cornucopia in 1987 on two of my upgraded Kaypros that eventually failed because of these 1793 chips, probably due to the heat issues involved with stressing the basic design of the system with these upgrades. It was one of my similar short publications to help others from my experiences.
E] 1] These Micro Cornucopia [MC] upgrades were just great, with very complete and understandable directions and quality parts, but you were really pushing the system way beyond what they were originally designed for, so there were some “break-in” issues that developed.
2] One was this heat generation, so if you have an upgraded Kaypro,
be aware of this. Comically, it was discovered when we put the tops back on our Kaypros. The people designing the upgrades never did this, since they were always “tinkering” with their systems. That is why I added a fan and even a perforated aluminum top to help cool them. Then all was fine.
E] One MC article even recommends just replacing the Tandons with half height good quality Japanese drives. It is easy and quite inexpensive. But I may note that there are some other considerations – setting the jumpers correctly, twisting the drive cables correctly, etc. But overall, no big deal if you are aware of these issues.
21] A] One of the best source of Kaypro technical information are the Micro Cornucopia journals of course. If they could be scanned and made available, it would be a great service.
B] Unfortunately, in our continuing downsizing in retirement, many years ago I could never have imagined I would ever need these journals again. We had moved on to Gateways, Compaqs, Gateways, Toshibas, etc. So they were tossed into the dumpster, along with much else from that era.
C] I do have some of the main articles, but they are marked up with my notes. In addition, it would be a big scanning job to do. Then there are the legal issues and how best to make them available and archived at a central location. Many are struggling with such issues for many computers today. Hopefully they will be eventually resolved in a satisfactory manner.
22] A] Also, another consideration of that era is the concept of “hypergrowth” that Osborne coined and is the title of his book on his company. I bring out some of this in the draft of my book on that era – “a computer built every 5 minutes!”.
B] For perspective, Tandon was selling “28,000 disk drives a month” to Kaypro alone! So right there you have a great potential for at least some bad drives getting into the system. Did you get one and others did not?
C] So some may be disappointed with some “issues” they may face with their Kaypros and other vintage computers, but for perspective, it is a miracle that so many were made so well and still work today from that early and so new era of computing!
D] I can say that all the Kaypros we got, 2 were new, and the 4 others used, were and still are incredible working machines. So rugged and so well designed and made. Again, like the Tucker cars of the 1940’s. But things change and life moves on, but what could have been if they could have continued profitably?
========================================================
So that is it for now. Hope some of this is of some interest and use.
I encourage all to please return the favor and continue to offer your input so we can all benefit.
If there is enough interest, then a lot of this Kaypro stuff can be pursued more intensively and even put on my web site. But right now, my information indicates that we are a very small group, so we will just have to try to do the best we can.
With the present global economy situation, it may take several years before we all get back to a time when we have more disposable income to devote to our hobby and to more substantially preserving these vintage computers.
All the best for 2009 and thanks for your interest and keeping those Kaypros and other vintage computers running!
Frank
Some additional background info if you are interested –
Please keep in mind, I am not a computer “techie!” I learned on my own what I had to learn to keep our systems going – we had a big investment in so many ways to try to protect and extend the usefulness of their lives, until we eventually went to more modern windows systems.
Also, my research for the draft of my book on these early portable, personal computers [PPC’s] – Osborne, Kaypro, Compaq, IBM, etc.] provided much additional information.
The draft is available as a free download on my website under the folder “Special,” if you are interested. Two publishers are now reviewing it for possible publication. But with the global economy as it is, I doubt either will be able to publish it. So I will eventually publish it on my own using our computer and inexpensive laser black and white printer. Any funds from such a publication will just go to fund my continuing STS research, which of course, includes vintage computers.
Please note that some of the files on this website, including this draft, got corrupted recently and when downloaded, appeared to be just simple text that was not very sophisticated and understandable. If this happens again, just let me know and I will have the web site provider fix it again.
Also, please ignore any “typos,” since I already spent a lot of time on this. But my wife is an English major and has very high standards!
tezza
Veteran Member
Frank,
Thanks for your comprehensive post. Certainly more than 2 cents worth!
I just got in after a day out and hope to digest some of what you've written tomorrow, when I can read it properly and digest it. I'll either get in touch via a PM or email or (if I think the info might also be useful to others) post something here.
You are right about the sturdy and repairable nature of Kaypros. One thing that highly impressed me was that EVERY CHIP on the circuit board is socketed, making for easy IC replacement.
Now you don't see that everyday. I wish that was the case on my PET!
Tez
Thanks for your comprehensive post. Certainly more than 2 cents worth!
I just got in after a day out and hope to digest some of what you've written tomorrow, when I can read it properly and digest it. I'll either get in touch via a PM or email or (if I think the info might also be useful to others) post something here.
You are right about the sturdy and repairable nature of Kaypros. One thing that highly impressed me was that EVERY CHIP on the circuit board is socketed, making for easy IC replacement.
Now you don't see that everyday. I wish that was the case on my PET!
Tez
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tezza
Veteran Member
Some quick notes just before I hit the sack..
Well, yes and no. Although I will play with the alignment at some stage, my gut feeling is I'll be better off just looking for a replacement drive.
I certainly know a lot more about drives now though. So much so, I've just managed to repair an old Apple DISK ][ drive this morning. It was broken when I got it (turned out the speed was way out)!
It's good to have an original configuration but I'm also a pragmatist. I'd be quite happy with a TEAC but it would have to be full height. I wouldn't want it to change the original external appearence of the machine.
As I mentioned before I did try to squeeze a TEAC full height drive in there. The card edge was in the middle of the drive rather than the at the side and was flipped the other way. Unfortunately the existing cable was just too short between the card sockets to connect them.
Yes, I'd been burnt with used floppies so they are all fresh out of the sealed box these days.
LOL! I remember the same kind of thing when doing big stat matrices, on my System 80
No, I don't know too much about it's history. I could probably get that info though.
I'll take a few more photos of the Kaypro naked and post them on here. As you say, it's an unusual machine and others might be interested.
I'll check out the serial number tomorrow and post it here.
There does seem to be a drive shield between the CTR and drives. It screws onto the bottom of the A drive.
No, I don't think this Kaypro was a NZ variation. It has "Made in the USA" on the back.
The System 80 was a TRS-80 Modl 1 "compatible", not a modified TRS-80. TRS-80 Mod 1s were sold here too. They were just hellishly expensive!
Yea, I don't think that's the problem here. They behave just the same out of the unit than in it.
No, I don't think this was the case. The previous owner said it had worked fine for many years. In fact, he had thown all his kaypro disks out because he thought he disks were faulty. He was quite devestated about that when I told him it was the drive.
More tomorrow...
Tez
Well, yes and no. Although I will play with the alignment at some stage, my gut feeling is I'll be better off just looking for a replacement drive.
I certainly know a lot more about drives now though. So much so, I've just managed to repair an old Apple DISK ][ drive this morning. It was broken when I got it (turned out the speed was way out)!
It's good to have an original configuration but I'm also a pragmatist. I'd be quite happy with a TEAC but it would have to be full height. I wouldn't want it to change the original external appearence of the machine.
As I mentioned before I did try to squeeze a TEAC full height drive in there. The card edge was in the middle of the drive rather than the at the side and was flipped the other way. Unfortunately the existing cable was just too short between the card sockets to connect them.
Yes, I'd been burnt with used floppies so they are all fresh out of the sealed box these days.
LOL! I remember the same kind of thing when doing big stat matrices, on my System 80
No, I don't know too much about it's history. I could probably get that info though.
I'll take a few more photos of the Kaypro naked and post them on here. As you say, it's an unusual machine and others might be interested.
I'll check out the serial number tomorrow and post it here.
There does seem to be a drive shield between the CTR and drives. It screws onto the bottom of the A drive.
No, I don't think this Kaypro was a NZ variation. It has "Made in the USA" on the back.
The System 80 was a TRS-80 Modl 1 "compatible", not a modified TRS-80. TRS-80 Mod 1s were sold here too. They were just hellishly expensive!
Yea, I don't think that's the problem here. They behave just the same out of the unit than in it.
No, I don't think this was the case. The previous owner said it had worked fine for many years. In fact, he had thown all his kaypro disks out because he thought he disks were faulty. He was quite devestated about that when I told him it was the drive.
More tomorrow...
Tez
tezza
Veteran Member
Thanks Dwight. Worth a go I guess. I'm assuming great care is needed to remove the flywheel. Any tips on how to do this? I don't want the stretch the belt.
Tez
tezza
Veteran Member
Pictures of the Kaypro II
Pictures of the Kaypro II
I've taken a few pictures of my naked Kaypro.
The Serial number on the back is 005322
1. First up a general picture with the cover off..
2. Here is a front-on picture of the two drives.
3. A top view of the drives. Note the metal cover on the base of the one nearest the monitor (shielding?)
4. A view under the circuit board left side by monitor.
5. The circuit board from the top. It has a number 45336 hand scrawled on it top right from the centre. Click here for a larger image.
6. Back of unit
Tez
Pictures of the Kaypro II
I've taken a few pictures of my naked Kaypro.
The Serial number on the back is 005322
1. First up a general picture with the cover off..
2. Here is a front-on picture of the two drives.
3. A top view of the drives. Note the metal cover on the base of the one nearest the monitor (shielding?)
4. A view under the circuit board left side by monitor.
5. The circuit board from the top. It has a number 45336 hand scrawled on it top right from the centre. Click here for a larger image.
6. Back of unit
Tez
Dwight Elvey
Veteran Member
Hi
Do not remove the flywheel. You can loosen the screws holding the motor.
This will give you enough slack to remove the belt.
You can spin the flywheel with your finger and hold a small piece of
fine sand paper to the surface.
Also check that the bearing is smooth. Sometimes the grease
dries and makes the balls lumpy.
Also check that the motor pully is smooth.
Dwight
Dr_Acula
Experienced Member
What a learned discussion! I'm not sure I'm worthy to even post on this one, but first, those pictures are great.
Back in the day I don't recall ever seeing a real Kaypro. But there were pictures around, so the hobbyists and enthusiasts built their own computers and modded them to look like kaypos. Brings back memories.
Socketed chips - someone was thinking ahead!
And by the looks of that motherboard, I'll bet that was laid out by hand. No fancy autorouter there!
I'm actively coding some software in CP/M 2.2 for the N8VEM that connects a board to a PC and turns a directory on the PC into drive P> in CP/M. Handy for doing something like PIP A:*.*=P:*.* It might be useful if you need to send some data across (is that D25 a serial port?).
As an aside, does anyone know where you get those little alfoil sticky things that go on EPROMs? Or even what they are called?
Not sure I can add much re the drives though. The mechanical parts are always the weak link.
As a general comment, it is interesting to see how much electronic parts have been 'standardised'. On that board are IDC headers, power connectors, right angle D plugs - all very familiar in modern computers. Yet go back 25 years before 1984 and very little stayed the same in those 25 years.
Back in the day I don't recall ever seeing a real Kaypro. But there were pictures around, so the hobbyists and enthusiasts built their own computers and modded them to look like kaypos. Brings back memories.
Socketed chips - someone was thinking ahead!
And by the looks of that motherboard, I'll bet that was laid out by hand. No fancy autorouter there!
I'm actively coding some software in CP/M 2.2 for the N8VEM that connects a board to a PC and turns a directory on the PC into drive P> in CP/M. Handy for doing something like PIP A:*.*=P:*.* It might be useful if you need to send some data across (is that D25 a serial port?).
As an aside, does anyone know where you get those little alfoil sticky things that go on EPROMs? Or even what they are called?
Not sure I can add much re the drives though. The mechanical parts are always the weak link.
As a general comment, it is interesting to see how much electronic parts have been 'standardised'. On that board are IDC headers, power connectors, right angle D plugs - all very familiar in modern computers. Yet go back 25 years before 1984 and very little stayed the same in those 25 years.
Dwight Elvey
Veteran Member
---snip---
> Socketed chips - someone was thinking ahead!
Hi
Sockets are one of the weakest points in old computers.
There would be much fewer problems without sockets.
I'd rather unsolder bad parts than deal with poor sockets.
--- snip---
> As an aside, does anyone know where you get those little alfoil sticky things that go on EPROMs? Or even what they are called?
I don't use foil. I just use white stick-on paper I get from the stationary store.
There is little to worry about erasing them. Paper blocks almost 100% of the
short wavelength UV. The adhesive block much of what is left over.
Metal foil is overkill.
Dwight
> Socketed chips - someone was thinking ahead!
Hi
Sockets are one of the weakest points in old computers.
There would be much fewer problems without sockets.
I'd rather unsolder bad parts than deal with poor sockets.
--- snip---
> As an aside, does anyone know where you get those little alfoil sticky things that go on EPROMs? Or even what they are called?
I don't use foil. I just use white stick-on paper I get from the stationary store.
There is little to worry about erasing them. Paper blocks almost 100% of the
short wavelength UV. The adhesive block much of what is left over.
Metal foil is overkill.
Dwight
patscc
Veteran Member
Fancy vs. Cheap
Fancy vs. Cheap
I'd call them eprom window covers, but that's probably about as accurate as alfoil sticky things.
If you're cheap, use duct tape (I've no idea if this even exists in Australia, but sure would like to know...)
If you're shooting for something fancier, perhaps like this, with a bit of scissor-work...
http://cgi.ebay.com/1000-SILVER-ROU...mZ320310112655QQcmdZViewItem#ebayphotohosting
Barring that, since the goal is to keep UV out, there's always black paint, black laquer, piece of a disk label... you get the idea.
Gotta agree with Dr_Acula on the pics. Shure is a pretty one.
patscc
Fancy vs. Cheap
I'd call them eprom window covers, but that's probably about as accurate as alfoil sticky things.
If you're cheap, use duct tape (I've no idea if this even exists in Australia, but sure would like to know...)
If you're shooting for something fancier, perhaps like this, with a bit of scissor-work...
http://cgi.ebay.com/1000-SILVER-ROU...mZ320310112655QQcmdZViewItem#ebayphotohosting
Barring that, since the goal is to keep UV out, there's always black paint, black laquer, piece of a disk label... you get the idea.
That's worth it's own thread. "When did automatic (or assisted ) trace routing of printed circuit boards first appear ?" or something like that.
Sounds cool. Is there something one can take a peek at ?
Until I had to reseat a board & clean corrosion between pins & sockets, I thought sockets were pretty cool, too. They rule for breadboarding, but for production...
Gotta agree with Dr_Acula on the pics. Shure is a pretty one.
patscc
patscc
Veteran Member
flywheel
flywheel
I could, however see it if the belt were glazed, or at least old, and there was irregular oxidation, as this would change belt "slippage"
I'm not trying to quibble, just trying to understand.
patscc
flywheel
I'm still trying to picture this. I thought that rot. speed has a 1% tolerance, typically. I can't see how an oxidation layer a few microns thick translates to enough to upset to the speed to exceed the 1% tolerance, unless there's something else marginal, like the bearings are worn, spindle warped, something like that.
I could, however see it if the belt were glazed, or at least old, and there was irregular oxidation, as this would change belt "slippage"
I'm not trying to quibble, just trying to understand.
patscc
tezza
Veteran Member
I would be interested in this too. Through a combination of software and hardware accessories I can transfer programs painlessly from my XP-enabled PC to my following vintage computers:
Vic 20 and Commodore 64
BBC
Atari 400/800XL/130XL
System 80
TRS-80 model 1
EACA Colour Genie
Apple IIe
IBM-PC
Tandy TRS-80 100
Compaq SLT/286
I'd love to add the Kaypro to this list.
Tez
Dr_Acula
Experienced Member
Thanks for the hints re eproms etc.
Comms between machines is very handy. I have a house full of computers - some giveaways, but back in the day you had just one, so there wasn't such a need to have them talking to each other.
The code I am working on is for the special case of a computer that had a seperate serial terminal, eg a WYSE. Is that how the Kaypro works, or does it do the keyboard to motherboard internally? If so, the code I'm working on won't be much use.
But all my early machines used dumb terminals driven via a serial port. Places like universities used to toss them out in the skip - eg out went the green ones because they now had orange ones. So I'd rummage around and get them for free. Then you just needed the "computer", ie the board and disk drives and power supply.
A PC can be used as a dumb terminal. Eg hyperterminal or teraterm. Or roll your own. Source code etc is at http://n8vem-sbc.pbwiki.com/ and scroll down the right and look in the folder Mini N8VEM VT100 and Drive P. It has some screen shots, a text file DriveP.txt that shows a session with PIP and STAT and DIR and ERA. The folder contains a compiled file where you just run setup and also the source files in vb.net. You might need the source files as I wrote it for 38400 baud and there is no menu to change that. But things like that can be added easily.
You need xmodem on the antique computer. And a serial port that goes to the dumb terminal. If you haven't got xmodem it gets tricky. The N8VEM starts off with CP/M and xmodem and nothing else at all. Even if you don't have xmodem, smart terminals are smarter than dumb terminals. A smart terminal could "type" in the entire hex code of xmodem, and then "run" LOAD to compile it. Of course, you then need LOAD. But only if that serial port can put things on the display as if they are being typed.
If the Kaypro has internal comms on the keyboard and display, but there is a serial port, there are still ways things can be hacked. I guess it depends how much software you have on the machine. I see LOAD and BAUD on the screenshot on page 1.
As an aside, I wonder if anyone ever networked CP/M machines via serial ports. Sure, there was MP/M with dumb terminals. And it is easy to join two computers with a null modem. But what about 3 computers? Did such a thing as an RS232 router exist? Or drive mapping in CP/M? That is my current project using a version of the N8VEM with 4 serial ports. That can be programmed as a router, and even with radio links. I'm thinking a setup where all the vintage computers could be linked to each other which would be very handy.
I hope you can get the drive working. The rest of the machine looks so good.
Comms between machines is very handy. I have a house full of computers - some giveaways, but back in the day you had just one, so there wasn't such a need to have them talking to each other.
The code I am working on is for the special case of a computer that had a seperate serial terminal, eg a WYSE. Is that how the Kaypro works, or does it do the keyboard to motherboard internally? If so, the code I'm working on won't be much use.
But all my early machines used dumb terminals driven via a serial port. Places like universities used to toss them out in the skip - eg out went the green ones because they now had orange ones. So I'd rummage around and get them for free. Then you just needed the "computer", ie the board and disk drives and power supply.
A PC can be used as a dumb terminal. Eg hyperterminal or teraterm. Or roll your own. Source code etc is at http://n8vem-sbc.pbwiki.com/ and scroll down the right and look in the folder Mini N8VEM VT100 and Drive P. It has some screen shots, a text file DriveP.txt that shows a session with PIP and STAT and DIR and ERA. The folder contains a compiled file where you just run setup and also the source files in vb.net. You might need the source files as I wrote it for 38400 baud and there is no menu to change that. But things like that can be added easily.
You need xmodem on the antique computer. And a serial port that goes to the dumb terminal. If you haven't got xmodem it gets tricky. The N8VEM starts off with CP/M and xmodem and nothing else at all. Even if you don't have xmodem, smart terminals are smarter than dumb terminals. A smart terminal could "type" in the entire hex code of xmodem, and then "run" LOAD to compile it. Of course, you then need LOAD. But only if that serial port can put things on the display as if they are being typed.
If the Kaypro has internal comms on the keyboard and display, but there is a serial port, there are still ways things can be hacked. I guess it depends how much software you have on the machine. I see LOAD and BAUD on the screenshot on page 1.
As an aside, I wonder if anyone ever networked CP/M machines via serial ports. Sure, there was MP/M with dumb terminals. And it is easy to join two computers with a null modem. But what about 3 computers? Did such a thing as an RS232 router exist? Or drive mapping in CP/M? That is my current project using a version of the N8VEM with 4 serial ports. That can be programmed as a router, and even with radio links. I'm thinking a setup where all the vintage computers could be linked to each other which would be very handy.
I hope you can get the drive working. The rest of the machine looks so good.
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SteveH
Experienced Member
Wasn't that CP-NET? Never used it myself, only every played with DR-NET and DARCNET network cards.
Great pics. reminds me of an LSI-M3 I once had.
Steve
MikeS
Veteran Member
There were definitely RS-232 "routers" as well as terminal controllers.
I have a bunch of Net Commanders (which I'd love to get rid of) which have 16 RS-232 ports, any one of which can be connected to any of the others either according to a programmable fixed route or ad hoc by preceding a session with a special addressing sequence; it also handles baud rate and handshake conversion with buffering.
Terminal controllers are similar but usually only connect a number of terminals to one common port (RS-232 and/or ethernet).
A related item is the statistical multiplexer, which is used in pairs: it multiplexes a number of terminals on to one pair of data lines or modem and then demultiplexes the data back to the same number of ports at the other end.
I have a bunch of Net Commanders (which I'd love to get rid of) which have 16 RS-232 ports, any one of which can be connected to any of the others either according to a programmable fixed route or ad hoc by preceding a session with a special addressing sequence; it also handles baud rate and handshake conversion with buffering.
Terminal controllers are similar but usually only connect a number of terminals to one common port (RS-232 and/or ethernet).
A related item is the statistical multiplexer, which is used in pairs: it multiplexes a number of terminals on to one pair of data lines or modem and then demultiplexes the data back to the same number of ports at the other end.