Yet another PET story

[MikeS]

Now that I'm confident of the accuracy of the dumps, here's an image of the Command-O ROM.

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Thanks! There's a lot of stuff out there for the PETs, but not all those odd ROMs and their docs are; good to save those images when we find 'em. Now I just have to make an adapter to install it in my 2001 (and maybe upgrade the standard ROMs while I'm at it). Might even inspire me to look at the stuff that isn't working...

 

[chuckcmagee]

Congrats on good ROMs. If ever needed, I have some 2532 EPROMs you can have, but at the moment my Data I/O Model 29B has a bad UniPak and I can not program PROMs. I hope that the UniPak only needs calibration which I am struggling to do, but it may be really broken and need replacement. Here is a link to a photo of the setup.

http://home.att.net/~betty.p.mercado/Old_Test_Equipment/Data_IO_29B.JPG

-Dave

I never did get the Data I/O that I own working. It was close when I got it off of ebay, never got close enough. I expended numerous hours reseating, examining solder joints, all that stuff. Must be time to figure out how the old Cromemco ByteSaver works instead.

 

[dave_m]

I never did get the Data I/O that I own working. It was close when I got it off of ebay, never got close enough. I expended numerous hours reseating, examining solder joints, all that stuff. Must be time to figure out how the old Cromemco ByteSaver works instead.

Cromemco, wow that's a famous old name. They had some good S-100 hardware. I've bought a lot of stuff on ebay. It's buyer beware there, but most sellers will answer your questions about self test passing and things like that. However usually they know very little about the equipment. One person told me the unit passed self test but would 'hang up' soon after. I took a chance and found out it had 'bouncing' keys that overflowed an input field and the unit would not allow any more input until a clear entry key was pressed. A little time spent with contact cleaner fixed the problem altogether. Here is a photo of some gear that is working nicely for me. I had used this type of test equipment in the 70's & 80's at North American Rockwell when they cost in the thousands, but now can be picked up fairly cheap on ebay. The logic analyzer is useful in troubleshooting old computers and a lot of fun to use, but they are hard to find with all the associated pods and test leads (flying lead sets). A logic analyzer is absolutely useless without them.
Regards, Dave

Lab Setup

 

[MikeS]

Yeah, Cromemco made some good stuff in their day; I still have about a dozen Cromemco systems of various models and conditions. To bring this back on topic, before I got my first PC I used a 6502 cross-assembler on a Cromemco to develop software for PETs and Rockwell AIM-65s; I never had a Bytesaver but I built homebrew EPROM programmers for both the PET and the AIM-65 and used those until I got a couple of commercial RS-232 programmers later on. Those were the days...

 

[dave_m]

To bring this back on topic, before I got my first PC I used a 6502 cross-assembler on a Cromemco to develop software for PETs and Rockwell AIM-65s; I never had a Bytesaver but I built homebrew EPROM programmers for both the PET and the AIM-65 and used those until I got a couple of commercial RS-232 programmers later on. Those were the days...

Yes, those were days of electronic adventure. I was already working for Rockwell when the 6502 family came out. We licensed it from MOS Technology/Commodore. Rockwell sold us the AIM-65 at half price to get us playing with them at home and if we wanted a PET to take home, they paid Commodore and took a little from our weekly pay checks until we paid them back. Super company. We used PETs in the labs as cheap IEEE-488 instrument controllers for our in-house test needs. 'Real' 488 controllers from HP were costing us $10-20,000. Later even the secretaries requested PETs for word processors (remember those terrible dot matrix printouts).

Of course about 1985 we all discovered the IBM-XT with its amazing 10MB hard drive...
Regards,
Dave

 

[cosam]

http://home.att.net/~betty.p.mercado/Old_Test_Equipment/Data_IO_29B.JPG

Nice! That puts my "eBay special" to shame. Then again, it did only cost me about $12 US, IIRC!

There's a picture of mine, featuring my go-faster 6332-to-2764 ROM adapter, on a new page I added to my site about verifying the ROMs the first time around. I also added one detailing the PCB repairs.

Anyway, I picked up some spare 4116 chips today to try piggybacking the RAM. I got a bit of a funny look in the shop as the guy knew exactly what they were and commented they must be about 20 years old. I replied that the ones I had were even older ;-) After a couple of minutes rummaging he returned with a big box full of the things. They'd probably been there a while because he didn't even have a price for them. He asked what it was for and, surprisingly, he was even familiar with the PET. Turns out that very shop, who haven't sold computers for donkeys years, used to sell PETs when they were new.

So I got back home and switched the PET on for some more troubleshooting. This time, however, there was something really weird on the screen - the BASIC prompt again! And that's before I even opened the bag containing the new RAM chips! I've really no idea what's going on, but I'm glad it's running again. Maybe all that farting around with ROMs has fixed a bad connection somewhere.

I guess I'll get back to the display problem again and hope the dreaded black screen of death doesn't come back. I'm not getting my hopes up, though...

 

[cosam]

Just plugged the Command-O in too, in UD3. The SYS 36864 command however drops me into some kind of monitor. Not what I was expecting, but quite cool:

http://www.cosam.org/images/pet/sys36864.jpg

MikeS: any luck with that manual? ;-)

Also a small update on the model number: I've found "4032" on (of all places) a hand-written label on the power cord. Would that be it?

 

[MikeS]

Yeah, Tezza's experience notwithstanding the dynamic RAMs and 6332 ROMs didn't cause problems too often (unlike the old 6540s & 6550s).

Always good to check the power supply connector; a little underrated and sometimes troublesome.

Good luck! We're rootin' for ya!

 

[MikeS]

Looks like we posted simultaneously ;-)

That sure doesn't look right; AFAIR you get dumped into the monitor when various illegal things happen. I assume that when you peek(36864) you do get the first byte of the ROM (76, I think)?

I did find the manual and it suggests that Command-O needs BASIC4, so you may be out of luck unless you can upgrade. Don't have a scanner available here at the moment, but I'll scan it anyway as soon as I do. I don't have a BASIC2 machine at the moment so I can't try your image right now.

As to the model number, I think 4032, 3032 and 2001N-32 all referred to the same model (9" screen, dynamic RAM PCB), but in different countries and with different keyboards, although the (substantially different) FAT40 was also known as a 4032, at least over here.

 

[MikeS]

You did remember to move it to the correct socket? SYSing to an empty socket would indeed drop you into the monitor.

Wonder of wonders, I found mine; here's what it looks like on my 8032:

 

[dave_m]

Nice! That puts my "eBay special" to shame. Then again, it did only cost me about $12 US, IIRC!

Thanks for the picture. Nice gadget and it works which is more than I can say.

After a couple of minutes rummaging he returned with a big box full of the things. They'd probably been there a while because he didn't even have a price for them. He asked what it was for and, surprisingly, he was even familiar with the PET. Turns out that very shop, who haven't sold computers for donkeys years, used to sell PETs when they were new

I wish I had a local place that stocked old parts. Those kind of places are long gone around here. However I found a good mail order place in Texas that stocks old parts. He tells you if they are unused or refurblished from socket pulls. The refurbs I got from him had good straight pins and clean UV windows.

 

[MikeS]

Yeah, some nice looking equipment on both your benches; nicer than mine fer sure.

Mind you, what I lack in quality I make up for in quantity: I've got 4 'scopes (1 Tek, 2 Philips and 1 Eico (!) ), 4 EPROM programmers, and a PC-based logic analyzer.

Cosam: now that it's sort of working, did you read Tezza's story about transferring software to/from his PET? Time to get it doing something! Have you got a tape or disk drive for it?

 

[dave_m]

Just plugged the Command-O in too, in UD3. The SYS 36864 command however drops me into some kind of monitor. Not what I was expecting, but quite cool:

http://www.cosam.org/images/pet/sys36864.jpg

MikeS: any luck with that manual? ;-)

Also a small update on the model number: I've found "4032" on (of all places) a hand-written label on the power cord. Would that be it?

I am unfamiliar with a PET with a 9" monitor and 32K RAM. Does yours have the small keyboard and cassette drive of a 2001 or a regular size keyboard?

Regards, Dave

 

[dave_m]

Mind you, what I lack in quality I make up for in quantity: I've got 4 'scopes (1 Tek, 2 Philips and 1 Eico (!) ), 4 EPROM programmers, and a PC-based logic analyzer.

The name Eico brings back memories! Did you build the scope? I built an Eico VTVM (vacuum tube voltmeter for the youngsters), a HiFi amplifier and FM tuner during my college days in the 60's. But my god, it would have taken me a year to build a scope. The trim pots alone would have put me over the edge.

Regards, Dave

 

[MikeS]

The chiclet keyboard and internal tape drive were only used on the first version of the 2001, with 4K and later 8K of (static) RAM; upgrade kits were available later to replace the upper case half and keyboard to look like the 4032 we're dealing with here.

http://www.commodore.ca/products/pet/commodore_pet.htm

http://en.wikipedia.org/wiki/Commodore_PET

Note that some references to the 40xx series are 9" models while others are 12"

Yeah, I built the Eico but it's a pretty basic 'scope; not quite as many trimpots as the Tek and Philips. It does use tubes though, as does the fine old Tektronix.

 

[dave_m]

I always wondered what these EPROM burners looked like!

Tez

PROM programmers like the Data I/O Model 29B were used in the engineering departments to fuse parts for experimental purposes (breadboards) or engineering model designs (prototypes). For production runs, parts would be procured from a distributor pre-programmed to your specification. Or if the run was very large, a ROM mask would be made.

The Model 29B was replaced around 1990 with the UniSite model which was more adapted for the higher speed and smaller size (surface mount) of the newer devices.

Of course this made the 29B obsolete and their resale value dropped like a rock. But for buffs of old hardware, they are perfect for programming the old +5 V dual in-line package (DIP) parts.

One real problem to note is that Data I/O upgraded their firmware often to add capability for new PROMs, so there are many versions (V numbers) of firmware not only in the main frame box, but especially in the UniPak (for PROMs) and LogicPak (for PALs) adapters as well as the in the little Program/Test (P/T) Adapters that go on the LogicPaks.

This was not a problem when the 29B was in production, if the user paid for the update service, they received new firmware (PROMs) for their machine on a regular basis. For a large company like Rockwell, the Data I/O representative would even come by with the mod kit and install them for you. But obviously some users did better than others at keeping their units at the latest version. When the 29B went obsolete, tons of them went on the market, unfortunately all at an unknown version levels.

For instance even to program very old parts like the PET EPROM (2532) or the 2732/2764 type EPROMs, one needs a UniPak of V07 or better. A Select Code EF will display the V level of the UniPak. I’m not sure of the last version of the UniPak, at least V018 or more. Even more problematic is for newer parts say like UV erasable AMD C22V10 PAL. For that, one needs a fairly late version (V009) of the 303A-011 P/T Adapter. If you get one on ebay and it turns out to be a V007, you are out of luck.

Be even more careful of older Data I/O products like the Model 19 or 29A as they will invariably have old firmware.

This is probably more than you ever wanted to know about the 29B, but it might save someone a problem.

 

[MikeS]

Since we're exchanging pictures, here's my B&C 1409 programmer, my two 2001 PETs (one with the keyboard upgrade), my PET EPROM programmer, a speech board and music interface, and a ROM expander. That particular 2001 PCB went down to the South pole BTW... ;-)

 

[MikeS]

Quadra ROM expander (since one usually had three or four different ones)

 

[Terry Yager]

Mike,

I just know that John (barythrin) won't think of it, but any guidance you could provide as to how to use the ROM expander would be greatly appreciated.

--T

 

[tezza]

Good to see photos of the gear Mike.

Tez