PGM Motherboard: Green Screen + Error 68K ?

PCB problems and fixes
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djsheep
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PGM Motherboard: Green Screen + Error 68K ?

Post by djsheep »

PGM motherboard was working this morning, but now I'm getting a green screen when booting up and the following message:

<<ERROR 68K: ED56 Z80ADDR: C10000 DATA: CD33>>

I can't access the PGM menu with the dip switch or button on the motherboard.

Any ideas?
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Re: PGM Motherboard: Green Screen + Error 68K ?

Post by Flinnster »

Oh dear. Ok have you checked the onboard battery?
I would put money on there being some trace damage.

I did some similar repairs previously.
Here are some of the key traces to check.
In your case I think it's very likely to be the pink (#4) clock signal trace:

Image
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Re: PGM Motherboard: Green Screen + Error 68K ?

Post by Flinnster »

Goes without saying.. if you have the original drum battery on there.. get it out quick:

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Re: PGM Motherboard: Green Screen + Error 68K ?

Post by djsheep »

Thanks for the replies. The motherboard is actually the later revision with a coin cell already installed.

It worked fine, then all of a sudden just died? If I change the 5V slightly I get an "address error" screen, flashing distorted colours, or a plain green screen. I'll keep trying to troubleshoot, and check that trace...
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Re: PGM Motherboard: Green Screen + Error 68K ?

Post by Flinnster »

Right, the trace lines are very different on the newer revision, so that photo above won't help much sadly.
I'd check your rear daughterboard connectors are all clean and it's making good contact, same with the game cart itself.

Beyond that hard to say really. Take a few nice clear pics of the area of the board with the battery on it, and around the 68000 and the z80.
I don't think any caps failing could cause this kind of thing, but who knows :(
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Re: PGM Motherboard: Green Screen + Error 68K ?

Post by djsheep »

Flinnster wrote:Right, the trace lines are very different on the newer revision, so that photo above won't help much sadly.
I'd check your rear daughterboard connectors are all clean and it's making good contact, same with the game cart itself.

Beyond that hard to say really. Take a few nice clear pics of the area of the board with the battery on it, and around the 68000 and the z80.
I don't think any caps failing could cause this kind of thing, but who knows :(
Here are some pics of the board and some areas that look a bit iffy actually!

http://djsheep.com/PGM1.JPG
http://djsheep.com/PGM2.JPG
http://djsheep.com/PGM3.JPG
http://djsheep.com/PGM4.JPG
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Re: PGM Motherboard: Green Screen + Error 68K ?

Post by Flinnster »

You have a multimeter? Maybe worthwhile just checking continuity on those bottom traces where the board has caught on things.
On the other photos the only other thing I spotted is that capacitors C3 & C5 (in the row next to the sound amp) might be starting to bulge out at the top?
Hmmm... and a possible missing capacitor at CB1 near the gnd & 5v pins on the jamma connector.
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Re: PGM Motherboard: Green Screen + Error 68K ?

Post by djsheep »

Flinnster wrote:You have a multimeter? Maybe worthwhile just checking continuity on those bottom traces where the board has caught on things.
On the other photos the only other thing I spotted is that capacitors C3 & C5 (in the row next to the sound amp) might be starting to bulge out at the top?
Hmmm... and a possible missing capacitor at CB1 near the gnd & 5v pins on the jamma connector.
Yeah, the two capacitors I'm going to get replaced. The bottom traces you mentioend I'm guessing are the suspect now, looks dodgy but couldn't focus on my phone... am unsure really if that's fixable? Will have a mate look at it. Also will check for that missing CB1 capacitor, it arrived without it, and worked, but who knows -- good spotting?! Thanks so much for yout time.
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Re: PGM Motherboard: Green Screen + Error 68K ?

Post by Flinnster »

Traces are definitely fixable yeah. Just need to find suitable solder points and bridge them with a wire.
No worries - hope you get it going again! :thumbupright:
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Re: PGM Motherboard: Green Screen + Error 68K ?

Post by digitron »

ERROR 68K:ED56 Z80ADDR:C10000 DATA: ED46

Updating after GC8Tech from AP got me pointed in the right direction. If anyone else has this problem with their PGM motherboard, it's most likely due to the two Z80 SRAM chips near the jamma edge. I got lucky, reflowed the solder for these two memory chips and the board booted right up. Otherwise you'll need to replace those memory chips.

https://www.arcade-projects.com/forums/ ... post161972
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