A NEC 8201a. A new resident at the rest home

[tezza]

On a rainy day you might want to look into it. "Purple Computing" made those portable drives and I'm fairly sure they worked with other brand names. You can resort to the tape cassette, as I believe the NEC has built-in support for "CLOAD/CSAVE" routines. BTW, those little PDD's weren't cheap. IIRC Radio Shack was selling them for @ $395 (usd) back in 1985. The company that I was working for at the time had a deal with Tandy, and we were able to purchase the Model 100 for about $395 or half price. Mine still works. Good luck with it.

Yes, I've got a tape deck for it, bought from someone on the VCF. See:
http://www.classic-computers.org.nz/blog/2011-09-26-a-nec-8201a-cassette-drive.htm

It works well.

In the day I used my original NEC 8201a all the time. Mostly for writing articles and lectures when I wasn't playing adventure games in bed :D . It was dead easy to upload the draft articles up into an IBM PC via RS232 where I could (in Wordstar) check it, do the final formatting, print it and save the article to disk for archiving. Thankfully I had argued that the PC needed a serial card. Those cards were hugely expensive those days. Anyway, given that our ONE departmental PC started to see some competition for use, it was great to have my own rugged portable word processor!

It was finally retired when I got my own office PC. I didn't need it anymore then, as the documents could go straight on the disk. By that time (1987?) Xywrite was the officially supported Word Processor.

Tez

 

[Agent Orange]

Here's a link you might find useful: http://www.atarimagazines.com/creative/v11n3/80_Portable_disk_unit_for_NE.php

 

[mevk]

SHE'S ALIVE!

Charged up 4 new nicads, rigged up a series connection, and popped em in the rechargeable battery pack. First time I turned on with the backup power switched to off position and nothing. Then turned that same button, located on the bottom of computer, to on position before firing up a second time and.... amazing - a little fireworks, in more ways than one. :-| First, a very dim screen that I could just barely make out magically lite up, flickered off, then lite up again. I managed to hold her steady and noticed that we were back in time -Jan.1, 1983. Cranked up the contrast, and behold there were more letters that proudly displayed three programs and displayed several more commands awaiting to be summoned upon -like a jeany waking up after a 20 year hiatus. After about another 5 minutes she must have been exhausted, and collapsed again. Gently turned her on again and after a brief respite she was back in the bottle, and again a few more times with the awakenings shorter each time until she could barely wake.

The low bat light was on the whole time, and I also thought that holding laptop in my hands may have triggered a bad connection too. So decided to lay her down on the table to do a brief burn in test to see if intermittent problem or low bat. After about a twenty minute rest,then laying on a stable desktop she ran like a champ -for about 15 minutes then conked out again and again. Still not sure what the problem is. Batteries could be low -they were charged for 8 hours and read 1.3 volts each, but after some mediocre soldering -I may have briefly short two of the bats, I still get 4.79 volts showing on my cheap multimeter when I take battery pack out of computer to test (4.8 is all it needs 1.2 volts/cell)? Also wondering if snipping out the little on board battery and leaving circuit open may have anything to do with low battery light. Finally, i believe that moving computer hastens a shut down so there may be a bad battery connection, faulty or lose chip somewhere.

I really don't have a clue on how to go about keeping "Jeanie" out of the bottle. Any idea(s) on where to start troubleshooting would be much appreciated.

CK

 

[mevk]

Should have known after discovering that cmos battery was unique. Battery pack does not take regular 1.2 volt AA but uses 1.5 volt Sum3 high volt batteries, and I can not find anywhere in nic/cad version?? Alternatives, -how about the zinc non-rechargeables?

 

[tezza]

SHE'S ALIVE!

Charged up 4 new nicads, rigged up a series connection, and popped em in the rechargeable battery pack. First time I turned on with the backup power switched to off position and nothing. Then turned that same button, located on the bottom of computer, to on position before firing up a second time and.... amazing - a little fireworks, in more ways than one. :-| First, a very dim screen that I could just barely make out magically lite up, flickered off, then lite up again. I managed to hold her steady and noticed that we were back in time -Jan.1, 1983. Cranked up the contrast, and behold there were more letters that proudly displayed three programs and displayed several more commands awaiting to be summoned upon -like a jeany waking up after a 20 year hiatus. After about another 5 minutes she must have been exhausted, and collapsed again. Gently turned her on again and after a brief respite she was back in the bottle, and again a few more times with the awakenings shorter each time until she could barely wake.

The low bat light was on the whole time, and I also thought that holding laptop in my hands may have triggered a bad connection too. So decided to lay her down on the table to do a brief burn in test to see if intermittent problem or low bat. After about a twenty minute rest,then laying on a stable desktop she ran like a champ -for about 15 minutes then conked out again and again. Still not sure what the problem is. Batteries could be low -they were charged for 8 hours and read 1.3 volts each, but after some mediocre soldering -I may have briefly short two of the bats, I still get 4.79 volts showing on my cheap multimeter when I take battery pack out of computer to test (4.8 is all it needs 1.2 volts/cell)? Also wondering if snipping out the little on board battery and leaving circuit open may have anything to do with low battery light. Finally, i believe that moving computer hastens a shut down so there may be a bad battery connection, faulty or lose chip somewhere.

I really don't have a clue on how to go about keeping "Jeanie" out of the bottle. Any idea(s) on where to start troubleshooting would be much appreciated.

CK

CK, Is the main battery pack designed for rechargeable batteries or standard batteries? I know the 8201a was sold with either a NICAD chargeable battery pack or a standard battery pack. Mine has the standard (non-chargeable one) you use with standard batteries.

One other question, are you using a WalWart or charger with it? My NEC will run happily with an external power pack and when it's running this way the low battery light should be off. I've used a 9V pack with mine and it seems to be ok. Just make sure the polarity is correct. I'm still a little uncomfortable using it being a slightly higher voltage than it should be, so no guarantees. Should be ok in short bursts though.

As to the computer suddenly shutting down when you move it, this is a known issue with the battery packs. They tend to be quite "loose" in the battery bay and movement can break the connection leading to instant shutdown. I'm sure this is the problem here. Exactly what you do about it, I'm not sure.

Tez

 

[mevk]

CK, Is the main battery pack designed for rechargeable batteries or standard batteries? I know the 8201a was sold with either a NICAD chargeable battery pack or a standard battery pack. Mine has the standard (non-chargeable one) you use with standard batteries.

One other question, are you using a WalWart or charger with it? My NEC will run happily with an external power pack and when it's running this way the low battery light should be off. I've used a 9V pack with mine and it seems to be ok. Just make sure the polarity is correct. I'm still a little uncomfortable using it being a slightly higher voltage than it should be, so no guarantees. Should be ok in short bursts though.

As to the computer suddenly shutting down when you move it, this is a known issue with the battery packs. They tend to be quite "loose" in the battery bay and movement can break the connection leading to instant shutdown. I'm sure this is the problem here. Exactly what you do about it, I'm not sure.

Tez

Tez, this is definitely the rechargeable version cause it has the serial number for rechargeable option written on it and the inside has no metal clasps for bats, but takes a sealed pack, and the inside also has a miniature long board with a resistor on it. Don't know what's inside of regular bat pack, or if rechargeable can be modified to regular. Still not positive what kind of battery this rechargeable pack takes, but if they are 1.5 volt that could explain why 1.2 volts doesn't have the juice. Would like to use it though and not have to alter if possible. The batteries fit snuggly in pack, but I'll recheck connections again, maybe scuff up or bend pack insert prongs ,etc.

In the meantime, I'll try this 9volt .5amp walwart, and cross my fingers.

PS Have you heard of anyone else having login problems? The only way I can log on is to link from original invite to join, otherwise it won;t recognize my username/password.

CK

 

[tezza]

PS Have you heard of anyone else having login problems? The only way I can log on is to link from original invite to join, otherwise it won;t recognize my username/password.

CK

Hmm..not sure what you mean by this. These original laptops had no logins. If you're wondering what the original interface looks like, you could also download VirtualT
http://sourceforge.net/projects/virtualt/

This is a TRS-80 Model 100 emulator that also has a NEC 8201a mode. At least then you have a play with the interface.

Tez

 

[mevk]

Hmm..not sure what you mean by this. These original laptops had no logins. If you're wondering what the original interface looks like, you could also download VirtualT
http://sourceforge.net/projects/virtualt/

This is a TRS-80 Model 100 emulator that also has a NEC 8201a mode. At least then you have a play with the interface.

Tez

I was referring to logging in to forum. I'm having difficulty logging on.

Bad news on the power supply. I plugged in downstairs and the polarity on that particular outlet is upside down so I may have fried something (just call me an idiot) The screen will light up on walwart power but shows no characters. Hve you ever heard of this one before?

In battery mode it still shows regular boot screen including Microsoft 1 OS but still only stays on a few seconds. So if I did fry something it is probably somewhere close to the power supply circuit. Hope this is not another brick.

CK

 

[tezza]

Bad news on the power supply. I plugged in downstairs and the polarity on that particular outlet is upside down so I may have fried something (just call me an idiot) The screen will light up on walwart power but shows no characters. Hve you ever heard of this one before?

In battery mode it still shows regular boot screen including Microsoft 1 OS but still only stays on a few seconds.

CK

Hmm..if you are still getting the OS on battery it doesn't sound like damage was done. You've tried adjusting the contrast when running on wall power? I may be that the characters are there, just an adjustment of contrast is needed on full power?

Try removing the battery pack and running on external power. If that doesn't work maybe soldering the internal NICAD back in and try on external power/no battery pack again.

There is a reset button there somewhere. Try pushing that too.

Tez

 

[mevk]

Hmm..if you are still getting the OS on battery it doesn't sound like damage was done. You've tried adjusting the contrast when running on wall power? I may be that the characters are there, just an adjustment of contrast is needed on full power?

Try removing the battery pack and running on external power. If that doesn't work maybe soldering the internal NICAD back in and try on external power/no battery pack again.

There is a reset button there somewhere. Try pushing that too.

Tez

When removed bat pack, walwart does nothing at all. If damaged, damage should be close to the power supply circuit but no clue as to how to find. Will check/magnify and resolder pack connections and board NICAD back in tomorrow, and check for reset button. Meanwhile its sleep time here in the states -9:40PM. What time is it there? Good day -or night depending.

 

[mevk]

So I soldered the old cmos battery back in just in case it was not supposed to be open but that had no effect -still dies shortly after turning on battery power, and with walwart power the laptop still displays a lighted screen but no dos/menu. Battery output is still around 4.8 volts, and according to back of rechargeable battery pack that is normal, which surprised me because that, I think this means laptop can operate at around 4 volts.

Noticed that the red LED light that warns of low battery comes on regardless of battery power or walwart power. So I'm thinking power supply is bad somewhere, but I really have no clue. So without fear I looked at service manual and noticed in troubleshooting area of power supply, it says that pin 3 of CN3 should be 9 volts with power supply and 4.5 volts with battery. My voltmeter shows 0.5 volts from walwart power, and -0.0 volts on pin 3 with battery power on. Pin 2, if that is worth anything, shows .5 from powersupply, and 4.7 battery volts. The manual further states if pin 3 is not 9 volts then Diode 8 is bad, but I tested it and it looks good to me (about .9 in forward direction and blocks in reverse direction). Next I looked at testing power supply pins and pin 3 is supposed to be -5 volts, pin 6 is supposed to be +5 volts, and pin 5 is supposed to be 0 volts. Well according to my measurements pins 1 through 9 are all +5 volts and pin ten is zero volts. Manual states power supply is bad, if results are not as stated above. Anyone have a spare power supply?

I know many of you out there could probably fix this in a flash, but I'm relatively clueless and could use some advice on how to interpret these tests, and how further to find any bad components to solve this low power problem.

CK

 

[tezza]

What's the voltage output from the WalWart when it's not plugged in?

Tez

 

[mevk]

Bad to worse

Bad to worse

What's the voltage output from the WalWart when it's not plugged in?

Tez

With multimeter prongs on end of walwart and totally disconnected from laptop, meter says 14.5 volts noload from the 9 volt wart with 350mah capacity.

Now battery power will not display dos menu but only flashes low voltage for a second, walart power now also just flashes the low battery for a second and no longer displays a lite up blank screen -don't know why there is no longer light to the screen now because voltages I think are still the same as before.

Not sure how it's possible but the original 30 yr.old cmos battery has recharged itself to 3.8 volts. Suspect that it may be shorted or will not hold a charge long, so I just took out the battery pack just in case.
Sure enough, after 20 minutes the cmos bat voltage is down to 1.25 volts and still sinking. Voltage from good battery pack that I just removed is still 4.6 volts so not sure why DOS is no longer displaying -maybe a capacitor is slowly dying? Also, do you know why there would not be negative voltages coming from either of the two power source, and why voltages seem so messed up, albeit differently, on both power sources?

CK

 

[tezza]

That internal NICAD sounds like normal behaviour for an old battery. If it's very old it might charge up initially, but then loose the charge very quickly.

Apart from that, I'm not sure what's going on. Given my lack of knowledge about these things it's probably best you engage with the guys on the club100 mailing list. They are helpful guys and might have seen the issue before.

Tez

 

[mevk]

Back again

Back again

That internal NICAD sounds like normal behaviour for an old battery. If it's very old it might charge up initially, but then loose the charge very quickly.

Apart from that, I'm not sure what's going on. Given my lack of knowledge about these things it's probably best you engage with the guys on the club100 mailing list. They are helpful guys and might have seen the issue before.

Tez

As a last ditch effort, thought I'd unsolder the nicads, recharge bats, re-solder another bat pack and hope I could get back to where I was. Amazingly it worked! She's been going for about 20 minutes and no crashes or low bat lights. I think what happened is that I accidentally left on bat power all night the other day. Nicads are only good for 5.5 hours according to manual. Today I tested the bat pack voltage and it was below 2 volts with a negative voltage on one cell. So either the board somehow shorted battery, or my poor soldering did when bat warmed up from being on so long.

Unfortunately, voltages are still no where near manual's voltages at specified locations. Been on 20 minutes and I suspect same thing will happen as last time -it will die pretty soon. However, if I recall correctly, I briefly shorted a battery on the first pack solder job and that droped pack voltage to about 5.1 volts and now with all replacement good bats, I have almost 5.5 volts. Even if computer goes a few hours, the max I can go according to manual is 5.5 hours without a walwart to charge these bats. Could try walwart again but maybe I should consult with guys over at the bitching club 100. Checked several components again, and not sure if I found anything that looked bad, other than a shorted diode that measured open in both directions -D2 (the diode that has the first connection to the bat pack and is on the power supply board.)

Just confirmed this laptop shuts itself down after 10 minutes of inactivity -nice feature. Still going strong after 45 minutes, and at least it appears that I did not harm anything. These things must be pretty rugged.:rockedov:



CK

 

[tezza]

As a last ditch effort, thought I'd unsolder the nicads, recharge bats, re-solder another bat pack and hope I could get back to where I was. Amazingly it worked! She's been going for about 20 minutes and no crashes or low bat lights. I think what happened is that I accidentally left on bat power all night the other day. Nicads are only good for 5.5 hours according to manual. Today I tested the bat pack voltage and it was below 2 volts with a negative voltage on one cell. So either the board somehow shorted battery, or my poor soldering did when bat warmed up from being on so long.

Unfortunately, voltages are still no where near manual's voltages at specified locations. Been on 20 minutes and I suspect same thing will happen as last time -it will die pretty soon. However, if I recall correctly, I briefly shorted a battery on the first pack solder job and that droped pack voltage to about 5.1 volts and now with all replacement good bats, I have almost 5.5 volts. Even if computer goes a few hours, the max I can go according to manual is 5.5 hours without a walwart to charge these bats. Could try walwart again but maybe I should consult with guys over at the bitching club 100. Checked several components again, and not sure if I found anything that looked bad, other than a shorted diode that measured open in both directions -D2 (the diode that has the first connection to the bat pack and is on the power supply board.)

Just confirmed this laptop shuts itself down after 10 minutes of inactivity -nice feature. Still going strong after 45 minutes, and at least it appears that I did not harm anything. These things must be pretty rugged.:rockedov:



CK

Looks like it might be (largely) OK. These old laptops are very heavy on battery use. They just drink power. From memory my NEC only lasted about 4-5 hours on alkaline batteries and NICADS would be much shorter.

Tez

 

[mevk]

Some brag about 20 hour bat life, so 4-5 is a little disappointing, but I guess memory size add-ons, game use, etc. all play a factor. Hope I can get PS working so can charge these damn bats without having to unsolder every dam time. Time to start scrounging around for a six volt supply.

Update -had laptop on for 1.5 hours last time and voltage dropped to 5.1 so not much air time is left. Compared to what these relics do they sure do suck up power, still, 1.5 hours is better than this old sony vaio laptop I'm typing on now does -about 1 hour if I use immediately after charged and it won't even hold a charge for more that 3 hours, if not plugged and not used.

BTW -what are your favorite programs that you have stored in ROM? Guess I'm going to have to find a cheap input source to get some programs loaded. No ever talks about using 3.5 floopies so that is a no go, and we tossed the old computer with 5.25. May try an old tape recorder but will have to find or modify a cord.


CK

Update: Found a 6volt 2amp(20x amp specified PS) that displays DOS with the low warning bat light. At least it may be working. Right now computer is turned off and PS is attached so according to manual it is charging my bats.

 

[MikeS]

Looks like it might be (largely) OK. These old laptops are very heavy on battery use. They just drink power. From memory my NEC only lasted about 4-5 hours on alkaline batteries and NICADS would be much shorter.

Tez

Something wrong there, Tez. Battery life is one of the plus points of these Kyocera-based beauties; Alkalines should last about 18 hours, and NiCds or NiMHs at least 6 hours or more. The wall wart should be 8.5V DC.

 

[tezza]

Something wrong there, Tez. Battery life is one of the plus points of these Kyocera-based beauties; Alkalines should last about 18 hours, and NiCds or NiMHs at least 6 hours or more. The wall wart should be 8.5V DC.

Well, it could have been longer. It's been 25 years. I seem to remember the batteries didn't last long but then maybe I used mainly standard non-alkaline ones. I haven't spend a whole battery-draining session on the one I have now so I haven't checked

Tez

 

[MikeS]

Well, it could have been longer. It's been 25 years. I seem to remember the batteries didn't last long but then maybe I used mainly standard non-alkaline ones. I haven't spend a whole battery-draining session on the one I have now so I haven't checked

Tez

Ah, OK; yes, cheap carbon/zinc or whatever they are these days would only give you about 6 hours or so, but I think when the subject came up on the M100 list some folks actually got around 40 hours out of some of those new high-capacity AA cells available today. Of course that's at the cost of no backlight, so you need a little booklight to use it in the dark.

And yes, for instance using the serial port substantially reduces run time.

So, mevk, what's the bottom line; is everything OK now?