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Vendetta PCB graphical errors [SOLVED]

mSlider

mSlider

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Hi folks!

I changed the capacitors on the Vendetta PCB and after going through everything and turning it on I see that it shows a graphical error: Only on the screens between phases and in player selection do some graphics appear with an orange background, when the background should be black.

Does anyone know what this could be due to? I think that changing the capacitors is pure coincidence, since they are located in the audio area and should not affect the graphical part at all.
It looks like something related to the priority of the layers or transparencies of some sprites.
I have the schematics but I don't know where to start looking, since doing the tests on the board everything is ok and the test colors are also correct.
Any ideas?

Some screenshots of the graphic problem:
vendetta_fault1.pngvendetta_fault2.png
 
Update (15-feb-2025):
I left the PCB on for a while (2-5 minutes) and it seems that the problem has disappeared. Even if I restart it, the problem is no longer there. But if I disconnect it for a while and reconnect it, the problem appears again.
My suspicion is whether the cause is due to temperature or if there is a capacitor (voltage problem) that takes a long time to charge.
 
So I actually had this same exact issue. It ended up being the traces, or soldering around the two 74LS273 chips. I just replace the 273s and made sure all the traces had continuity. Mine works fine now and never had that problem again. Hope this helps
 

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HardAzRockz said:
So I actually had this same exact issue. It ended up being the traces, or soldering around the two 74LS273 chips. I just replace the 273s and made sure all the traces had continuity. Mine works fine now and never had that problem again. Hope this helps
Click to expand...
Thanks for the help, at least I've been able to start looking somewhere

Update (23-feb-2025) :
I have tried mounting the 74LS273 on top of those two that @HardAzRockz indicated without success, it continues doing the same thing.
I have also tried re-soldering some solders in the bottom but nothing changes.
The pcb behaves the same: it starts up and in the selection menu and between stages the background of the letters and some graphics appear orange instead of black, and after a few minutes it looks fine again until I disconnect the board and let it unpowered for a few minutes, and back again.
I've tried to pre-heat the board a little before power up, but seems that is not a heat/bent/broken traces problem???
 
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I believe I had some trace or vias(can’t remember)damage around the 273s (on the top side). Try applying little finger pressure to the area while it’s on. I found my fault by accident. I noticed when I pushed down slightly it would fix or make worse. Hope that helps
 
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I've tried pushing almost all the IC's but nothing changes (seems that are working testing with the logic probe), I will desolder those 273s and see if any underneath trace is making weak contact or broken.
I've ordered some 273s just in case, will see...
 
Update (27-feb-2025):
The 273s arrived are replaced after I added a pair of sockets. Same issue, nothing change.
Inspected the traces and probe pin by pin on those 273s and all make good contact. I think I can rule out those ICs now. ;-)
I try to bend the pcb and push every single IC, and the image is rock solid, only after a few minutes powered on the issue dissapear.
The next thing I suspect it might be the RAM chips or the PAL's, because they are the first of getting warm, will see...
 
I did replace some other ICs (don’t remember which) to get it working initially. Shortly after I got it working the purple hue (discolored graphics) appear randomly and disappear after turning it off. I would try to find the schematics. It could be something in line with the 273s or potentially ram. I’m no expert. I’ve fixed a bunch of boards but sometimes I got lucky and sometimes it was obvious.
 
Update (01-mar-2025):
Today I use the hot air gun to prove the "temperature" warm issue theory, I have heated the PCB on the side opposite the jamma connector (custom Konami graphic chips zone) and power it on, the problem is gone, I did it 3 times this process (letting the PCB cool between tests) to confirm.
The most obvious thing is to reflow those IC's (I suspect is some kind of cold join on one of those IC pins)...
 
Glad to hear you solved your issue. Like I said something wasn’t making a connection on mine. I always reflow the chips on repairs. The solder is old and reflowing rejuvenates. You must have had a pin or two on the Konami custom that was flaky. Good job
 
HardAzRockz said:
Glad to hear you solved your issue. Like I said something wasn’t making a connection on mine. I always reflow the chips on repairs. The solder is old and reflowing rejuvenates. You must have had a pin or two on the Konami custom that was flaky. Good job
Click to expand...
It's not solved, I still have to try to reflow those ICs. But the problem is getting more and more limited, let's hope that's it... I'll post with the results soon.
 
Update (03-mar-2025):
Today I start reflowing, first the 053251 Konami custom and boom!, after that I powered on the board and no sign of "orangeish" background color issue.
To confirm I let it cool down for about and hour and power on it again, seems the problem is finally solved.

Conclusion: It was some cold join on the 053251 Konami custom IC (it was difficult to check because it did not change even when applying pressure).

Thanks to @HardAzRockz for bring me some light to the problem.


*for illustration purposes I add the picture of the reflowed IC:
vendetta_fault4.jpg
 
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