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Display problems on a Commodore Pet 8032

Alternative set? Do you mean those boards originally had a 4K ROM, but in mine the importer (likely Datatronic or reseller) installed 2K EPROMs with Swedish character set?

Actually I had some idea about designing my own character set and use instead of the original one. For instance the C64 character set would be a good candidate and give characters with wider vertical lines.

As for my 2 kB chips collection, those are five TMS2516, seven MM2716Q, four OKI MSM2716AS plus a single one each of AMD 2716 and NEC D2716D. All OKI's but only one of the MM2716Q's has gold plated legs. In this case I don't know if it preferred or not.
 
carlsson said:
Alternative set? Do you mean those boards originally had a 4K ROM, but in mine the importer (likely Datatronic or reseller) installed 2K EPROMs with Swedish character set?
Click to expand...

Anders, I doubt that the machines came with 4K character generator ROMs. But if you chose to install a 4K EPROM, the design supports the capability of switching between two 2K character sets. There is a line from the CRT controller called Character Option that is connected to pin 18 of the ROM. If the ROM is a 2K part, pin 18 is just an extra chip enable, but in a 4K ROM, it is address line A11 which allows addressing of the upper 2K ROM space. I suppose it could be used under program control to switch between the Swedish character set and any other set.
 
Ooh.. that was new knowledge to me. I was happily surprised when I spotted a 40 column PET that boots up in lower case, but afterwards I realized they all (?) actually have both upper and lower cases, selectable through CHR$ or a POKE.
 
I just wanted to publicly thank Anders Carlsson for sourcing and arranging for me a couple of chips to try. :super:

I hope you all agree, Its turned into a really interesting thread, I apologise that I can't contribute personally but I admire all your technical knowledge.

As soon as the post arrives I shall trial Anders replacement and let you know the results.

:workout2:
 
Well this thread inspired me to pull out my 3 dead 8032 boards and get them repaired, sadly when i booted the 8032 it chirped flashed and died. Now I have 4 boards to repair.

I didn't see it mentioned but this company seemed a great source of parts not sure if they ship international or not. http://www.unicornelectronics.com I was able to get the 2532's and 2716's (luckily my BK programmer handles them) along with all the logic and 6500 chips. So hopefully i'll get mine up an running.
 
polishedball said:
Well this thread inspired me to pull out my 3 dead 8032 boards and get them repaired, sadly when i booted the 8032 it chirped flashed and died. Now I have 4 boards to repair.
Click to expand...

Oh, that's not fair. The beep meant it passed its power on check, but then apparently the PET expired. Tell us what the condition is now. White screen, dark screen, garbage screen, no response, etc.
Do you have a voltmeter to check the power supply voltages?
 
All these Pets dying....

Maybe I should pull mine out again just to give the circuits some exercise? ;)

Knowing my luck I'll immediately have an issue. This is to stop me getting bored of course... :tellme:

Tez
 
I wonder how many working models are left? Anyone care to hazard a guess?

I'm going for... hmm... 450

to high? :lookroun:
 
MikeS said:
That's why I said to look for 2716s and TI 2516s as well as 2532s; this discussion seemed to assume that the CG ROM is a 4K 2332/2532 type instead of the much more common 2K 2716 type (probably because of the suggestions to replace it with a 4K ROM from elsewhere for testing).
Click to expand...
Yeah, I've been flying on instruments at this end - I only have the schematics to look at and the CG is marked as "2316 or 2332" and all others are one or the other. I can never remember which 27xx and 25xx are equivalents ;-) A 4K ROM in a 2K socket should still work though, and it also explains:

dave_m said:
But if you chose to install a 4K EPROM, the design supports the capability of switching between two 2K character sets. There is a line from the CRT controller called Character Option that is connected to pin 18 of the ROM. If the ROM is a 2K part, pin 18 is just an extra chip enable, but in a 4K ROM, it is address line A11 which allows addressing of the upper 2K ROM space. I suppose it could be used under program control to switch between the Swedish character set and any other set.
Click to expand...
Which is new to me too, sounds like a cool feature.

tezza said:
All these Pets dying....
Click to expand...
It does seem that a lot are reaching their use-by date all of a sudden, doesn't it? Or maybe the number of PET repair threads here is drawing Googlers to this forum ;-) Does make me wonder how many machines may have been discarded as "junk" whilst actually being quite easily repairable.

Anyway, here's hoping the new CG winging its way to the OP will help save this PET from such a bitter end. My going-on about testing the shift register will probably be enough to ensure that there's absolutely nothing wrong with that part ;-)
 
carlsson said:
All OKI's but only one of the MM2716Q's has gold plated legs. In this case I don't know if it preferred or not.
Click to expand...

Anders,
My guess is that if the part was destined to be soldered into a board, a tin plated lead would be best.

But if the part was meant for installation into a socket, the gold plate would best. Gold has good electrical properties plus it does not tarnish easily.
-Dave
 
mrmacca said:
I wonder how many working models are left? Anyone care to hazard a guess?

I'm going for... hmm... 450

to high? :lookroun:
Click to expand...
If you count all models I think you'd be surprised; I know of about 25 just among three or four local friends and I wouldn't be surprised if there were a hundred or more just in the greater Toronto area. After all, any collection of significant vintage computers has to include at least one PET.

Bo Zimmer, Steve Gray, Jim Brain and Anders alone probably have 450 units among them ;-)

Don't forget that many thousands were put into schools, at least in Canada and the US.

Mind you, considering the current theme of this thread maybe instead of "working" we should say "working the last time they were turned on" ;-)
 
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dave_m said:
Anders, I doubt that the machines came with 4K character generator ROMs. But if you chose to install a 4K EPROM, the design supports the capability of switching between two 2K character sets. There is a line from the CRT controller called Character Option that is connected to pin 18 of the ROM. If the ROM is a 2K part, pin 18 is just an extra chip enable, but in a 4K ROM, it is address line A11 which allows addressing of the upper 2K ROM space. I suppose it could be used under program control to switch between the Swedish character set and any other set.
Click to expand...
As a matter of fact there is a 4K Swedish Character Generator ROM for the SuperPET on Zimmer's ;-)

But I was wondering if the alternate character set was ever used for anything other than the SuperPET's APL characters. I had (have) an alternate set in my old 2001 but it was selected with a switch; never got around to looking at how they're selected on the 8032 etc.; presumably just a poke to one of the CRTC registers.

I kind of got interested in this during a discussion on another forum about Japanese character sets; I've got a Japanese keyboard and my girlfriend is studying Japanese so I thought it'd be fun to have a Japanese PET, and that would require using the upper 2K of the CG space.

Anybody ever see an article in any of the mags about playing with this? I'd be surprised if there weren't any.
 
dave_m said:
Mike,
No I haven't but having the right keyboard to sure a good start for this project. Have you seen the info on the VIC-1001, the Japanese VIC?

http://zimmers.net/cbmpics/cvic1001.html

-Dave
Click to expand...
Yeah; I think that's where one version of the Japanese character set for the PET came from. A fellow in Tokyo has a Japanese PET that died and in his investigations he made a new CG ROM from the Japanese VIC set; I've got a version installed in my 2001 PET as a switch-selectable alternate 2K set.

It would be nice though to have access to upper and lower case, PET graphics, and the alternate character set all on the same screen; I suspect it's not possible with standard hardware but I'm thinking that maybe I could use the reverse-video line to switch CG banks.

Just not enough time to play with all the toys, especially If I spend much more writing posts like this one ;-)
 
MikeS said:
If you count all models I think you'd be surprised; I know of about 25 just among three or four local friends and I wouldn't be surprised if there were a hundred or more just in the greater Toronto area. After all, any collection of significant vintage computers has to include at least one PET.

Bo Zimmer, Steve Gray, Jim Brain and Anders alone probably have 450 units among them ;-)

Don't forget that many thousands were put into schools, at least in Canada and the US.

Mind you, considering the current theme of this thread maybe instead of "working" we should say "working the last time they were turned on" ;-)
Click to expand...

So I've really under estimated how many remain then! I think the PET to be a more popular machine outside the UK. Our biggest seller was the BBC.

I've uploaded some of our bits and bobs here in a new thread. :

http://www.vintage-computer.com/vcf...-Some-Uk-University-Stuff&p=133514#post133514
 
Back on Topic :

Would a 8224 ETC2716Q-1 or a 8428 ET2716Q-1 Eprom Chip be what I am looking for? As I have found these with 24 pins.
 
mrmacca said:
Would a 8224 ETC2716Q-1 or a 8428 ET2716Q-1 Eprom Chip be what I am looking for? As I have found these with 24 pins.
Click to expand...
Either of those should do, assuming they are fast enough. The first four digits are the date code (manufactured in 24th week of '82 and the 28th week of '84 respectively) so they are in fact almost the same part. If you can program one of those with the right image you ought to be in business.
 
What does the ETC stand for? Someone here has suggested its like TI is Texas Instruments and that ETC could be the old Thomson company? :eek:
 
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