Bryan Posted January 24, 2016 Share Posted January 24, 2016 Thanks a lot ! My PAL 800 board is the one from the bottom left in your pictures. So I cannot replace a 6502C by a 6502B, but can you confirm that I cannot also replace a 6502B by a 6502C ? Unfortunatly I do not have any XL/XE computer ... They cannot be swapped either way. They interface to the system bus differently. Quote Link to comment Share on other sites More sharing options...
Dizzy Posted January 24, 2016 Author Share Posted January 24, 2016 Thanks a lot. So I have no other choice than buying a 6502C without being sure that the problem comes from it ... Quote Link to comment Share on other sites More sharing options...
russg Posted January 25, 2016 Share Posted January 25, 2016 (edited) I'm not familiar with UK/Germany/EU companies. You can look in the Atari8bit FAQ and get EU companies. http://faqs.cs.uu.nl/na-dir/atari-8-bit/faq.html Nope, That not it. You want the Atari 8-bit vendors and developers list. You can find it from the A8 FAQ mentioned. Nope again: at... http://www.faqs.org/faqs/atari-8-bit/vendev/ ... It has lots of EU vendors, but I did a quick look-see and didn't see much hardware vendors. It was too many to read. I know Best has the 800 CPU PAL card. Edited January 25, 2016 by russg Quote Link to comment Share on other sites More sharing options...
Joey Z Posted January 25, 2016 Share Posted January 25, 2016 (edited) They cannot be swapped either way. They interface to the system bus differently. Actually, they work almost exactly the same as each other, with the one exception of the /HALT pin. If you tie this pin to 5V, then a 6502C should work in place of a 6502B. You may not even need to, if the /HALT pin floats high (as many TTL compatible inputs do), although even if it does, you'd best tie it to +5V somehow, since this is not in any way a guaranteed behavior. Edited January 25, 2016 by Joey Z Quote Link to comment Share on other sites More sharing options...
Rybags Posted January 25, 2016 Share Posted January 25, 2016 (edited) I think it's a bit more complex than that. Sally also reassigns the RW pin, for whatever reason (the original just becomes NC). Possibly the halt circuitry is something off-chip and it was just a physical requirement (has anyone decapped a Sally?) Though of course if you made up an adaptor with proper reassignments there's no reason a Sally shouldn't substitute for a 6502B. Edited January 25, 2016 by Rybags Quote Link to comment Share on other sites More sharing options...
Dizzy Posted January 25, 2016 Author Share Posted January 25, 2016 (edited) There is still something I cannot explain : I know the problem comes from the CPU board, but not from Antic or GTIA. So the last guilty processor may be the 6502, or a small electronic component (like a resistor). But I do not understand why a cartridge game works fine ? If my 6502C is bad, why does it work fine when intensively used for running a cartridge, why is it crashing when just typing a text in notepad or Basic ? It is a non sense to me, I really cannot explain that, does anybody has an idea of the differences in the CPU (6502) usage while running a cartridge game or while just typing a text in the notepad ? Edited January 25, 2016 by Dizzy Quote Link to comment Share on other sites More sharing options...
Bryan Posted January 25, 2016 Share Posted January 25, 2016 Flaky CPUs can be subtle. You can have a leaky or slow transistor in the CPU that causes certain operations to fail, but others to succeed. It can even be temperature dependent. In this case, some software will work and some won't. If you have a 7474 or 74LS74 on the other board, you can try swapping it for the 74LS74A Quote Link to comment Share on other sites More sharing options...
Keatah Posted January 25, 2016 Share Posted January 25, 2016 Yeh. man, like IDK and stuff. Now that things have been swapped out via trial and error. Maybe a more technical approach is needed with scopeses and meeders and stuff. Quote Link to comment Share on other sites More sharing options...
Bryan Posted January 25, 2016 Share Posted January 25, 2016 Dizzy, check Apolloboy's status update. Quote Link to comment Share on other sites More sharing options...
Dizzy Posted January 25, 2016 Author Share Posted January 25, 2016 Dizzy, check Apolloboy's status update. I'm sorry but what do you mean ? Quote Link to comment Share on other sites More sharing options...
ApolloBoy Posted January 25, 2016 Share Posted January 25, 2016 (edited) Unfortunately the CPU boards I came across yesterday were all older boards with the 6502B. I could try checking again today or tomorrow though. I'm sorry but what do you mean ?I came across a stash of 400/800 CPU and memory boards yesterday at a local computer surplus shop I frequent, I posted a status update asking if anyone wanted one since I have no need for them and I'd love to see them go to the community. Edited January 25, 2016 by ApolloBoy Quote Link to comment Share on other sites More sharing options...
Dizzy Posted January 25, 2016 Author Share Posted January 25, 2016 Thanks a lot anyway. I will now buy a 6502C on ebay ... and I will cross my finger hopping the faulty component was it .. Quote Link to comment Share on other sites More sharing options...
ClausB Posted January 26, 2016 Share Posted January 26, 2016 Or you could buy a whole CPU board with a 6502B on it and swap in your PAL ANTIC and GTIA. 1 Quote Link to comment Share on other sites More sharing options...
Bryan Posted January 26, 2016 Share Posted January 26, 2016 Or you could buy a whole CPU board with a 6502B on it and swap in your PAL ANTIC and GTIA. Is there a PAL version of the old board? Quote Link to comment Share on other sites More sharing options...
tep392 Posted January 26, 2016 Share Posted January 26, 2016 Flaky CPUs can be subtle. You can have a leaky or slow transistor in the CPU that causes certain operations to fail, but others to succeed. It can even be temperature dependent. In this case, some software will work and some won't. I experienced one of these odd failures on my 5200. After the CPU warmed up, the ghosts in my Pac-man Arcade cart would start passing through the maze walls. The game didn't lockup. The games logic just started to fail. Swapped in the CPU from my 800XL and works fine now. 1 Quote Link to comment Share on other sites More sharing options...
Dizzy Posted January 27, 2016 Author Share Posted January 27, 2016 Or you could buy a whole CPU board with a 6502B on it and swap in your PAL ANTIC and GTIA. PAL CPU Boards are very hard to find (a PAL ANTIC and GTIA would not work properly on an NTSC CPU board, already tried ...). Quote Link to comment Share on other sites More sharing options...
russg Posted January 27, 2016 Share Posted January 27, 2016 PAL CPU Boards are very hard to find (a PAL ANTIC and GTIA would not work properly on an NTSC CPU board, already tried ...). I already gave info where one place (Best Electronics) has UK/PAL 800 CPU boards. see earlier post in this thread. Quote Link to comment Share on other sites More sharing options...
Dizzy Posted January 27, 2016 Author Share Posted January 27, 2016 (edited) I already gave info where one place (Best Electronics) has UK/PAL 800 CPU boards. see earlier post in this thread. I know, thanks again, but this website is just horrible : different colors and underligned texts everywhere, you do not know where to click ... impossible to find what I was searching for : where do you see a PAL cpu card there ? I sent an email with no response. And even if they would have answered, the cost of the cpu card plus the shipping price for France would be too high I guess. PAL CPU cards are hard to find in Europe. Edited January 27, 2016 by Dizzy 1 Quote Link to comment Share on other sites More sharing options...
Kyle22 Posted January 28, 2016 Share Posted January 28, 2016 The web page is horrible, but the parts are good http://www.best-electronics-ca.com/800.htm Quote Link to comment Share on other sites More sharing options...
russg Posted January 28, 2016 Share Posted January 28, 2016 (edited) I know, thanks again, but this website is just horrible : different colors and underligned texts everywhere, you do not know where to click ... impossible to find what I was searching for : where do you see a PAL cpu card there ? I sent an email with no response. And even if they would have answered, the cost of the cpu card plus the shipping price for France would be too high I guess. PAL CPU cards are hard to find in Europe. Kyle22 gave the URL to PAL 800 CPU board. I think it is a UK board, so you'd have to e-mail them about France. They're very specific about e-mail. You just have to have 'Atari' in the subject line or the message is deleted as spam. It would cost you US $20 plus about US $20 ship. Put, say 'Atari 800 CPU board' in the subject line. I know it is frustrating and expensive, but I don't know an option. Maybe try ebay. $40 is a lot to pay. You might get an entire 800 for that on ebay. edit: No you can't get an entire 800 for $40. Edited January 28, 2016 by russg Quote Link to comment Share on other sites More sharing options...
Rybags Posted January 28, 2016 Share Posted January 28, 2016 If it was me I'd just buy an XL, chances are it'll have a socketed CPU which can be harvested for testing the board. Quote Link to comment Share on other sites More sharing options...
Dizzy Posted January 28, 2016 Author Share Posted January 28, 2016 The web page is horrible, but the parts are good http://www.best-electronics-ca.com/800.htm Thanks for this direct link ! 19.95$ is a good price, I sent another email, and had a resonse saying we need to order for at least 20$ ... I still do not know what would be the shipping cost but probably around 30$. So 50$ is a lot to pay, this is the exact price I paid for my PAL ATARI 800 (with a few accessories, box, documentation, cables, etc ...) which was a good price, I know ... So I am still waiting for to receive the Sally I ordered on Ebay (17€ shipping cost included) and still hope it will work. Of course, buying a whole cpu card would be safer. I will also pickup an Atari 800 XL I bought yesterday (but not to fix my 800 !). Quote Link to comment Share on other sites More sharing options...
Bryan Posted January 28, 2016 Share Posted January 28, 2016 If it was me I'd just buy an XL, chances are it'll have a socketed CPU which can be harvested for testing the board. Especially 600XLs. I don't think I've ever seen one without sockets. In fact, I can't find a Google image without sockets. How about this: eBay Auction -- Item Number: 291664231104 1 Quote Link to comment Share on other sites More sharing options...
russg Posted January 28, 2016 Share Posted January 28, 2016 Thanks for this direct link ! 19.95$ is a good price, I sent another email, and had a resonse saying we need to order for at least 20$ ... I still do not know what would be the shipping cost but probably around 30$. So 50$ is a lot to pay, this is the exact price I paid for my PAL ATARI 800 (with a few accessories, box, documentation, cables, etc ...) which was a good price, I know ... So I am still waiting for to receive the Sally I ordered on Ebay (17€ shipping cost included) and still hope it will work. Of course, buying a whole cpu card would be safer. I will also pickup an Atari 800 XL I bought yesterday (but not to fix my 800 !). That is not on the up and up. Refuse your order because of a nickel, when you and they know it will take more than a nickel to ship it. Quote Link to comment Share on other sites More sharing options...
Dizzy Posted February 2, 2016 Author Share Posted February 2, 2016 (edited) Bad news ... the 6502C replacement did not solve my problem ... And I still cannot understand this strange situation : - If I replace the current 6502C by a 6502B (new one), then when I power up the Atari 800 I get a brown screen. - If I replace the current 6502C by a 6502C (new one), then when I power up the Atari 800 I get a brown screen (same result !). - If I put back the original 6502C, then the cartridges work fine, the only problem is when using basic or notepad : freezes after a few seconds of use ... So if the problem does not come from the CPU (or GTIA / Antic), why only the original CPU work almost fine (but not well) ? Anyway, now that I have a 800XL, can I swap the Antic / GTIA from it to insert them into the 800 ? (I don't think so as Rybags told me they are unic to each system...) I guess that now I will have no other choice than buying a new PAL CPU board ... Aaargh ! Edited February 2, 2016 by Dizzy Quote Link to comment Share on other sites More sharing options...
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