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CPS2 sound issues

@Raph_friend I see you too had the displeasure of working on a board full of WD40... It's horrible.

Also:
Parabéns pelo seu guia de reparação para as placas CPS2. Muito bom mesmo!

(Congrats on your CPS2 repair guide! It's really good!)
 
Never use normal wd40 on pcbs unless you want to ruin it in a few months.
 
ic3b4ll said:
@Raph_friend I see you too had the displeasure of working on a board full of WD40... It's horrible.

Also:
Parabéns pelo seu guia de reparação para as placas CPS2. Muito bom mesmo!

(Congrats on your CPS2 repair guide! It's really good!)
Click to expand...
Thanks!
Obrigado!
Arigatou gozaimashita!
 
ic3b4ll said:
white stains because it will dissolve the flux residue
Click to expand...
Not to derail the thread too much, but I've seen this on some boards quite often after an initial cleaning with IPA, and never could find the best chemical to remove it easily without a lot of scrubbing and repeat rinsing with more IPA. Any suggestions?
 
adgenet said:
ic3b4ll said:
white stains because it will dissolve the flux residue
Click to expand...
Not to derail the thread too much, but I've seen this on some boards quite often after an initial cleaning with IPA, and never could find the best chemical to remove it easily without a lot of scrubbing and repeat rinsing with more IPA. Any suggestions?
Click to expand...
Have encountered same and did not find other way around getting that white stuff off. Soft or medium hard toothbrush is a good tool, btw.

I found another "reason" for using the WD40... You'll get rather dirty PCB with caps leakage marks looking good when you have thin oil film applied. Pictures will look nice, the PCB has somewhat new/clean outlook when the oil makes surfaces nice and shiny.
 
why? I mummified all my PCBs lol. Actually only the expensive shmups. I think hard to work on them if there is a problem, but I asked around a few electronics guys, havent got any response that told me it was bad. Interested in knowing why it's a bad thing.
 
It's good in a way because it adds a protective layer, a lot of operators like it.

The problem is the stuff is an absolute dust magnet and arcade PCBs in a cab or on a shelf in a warehouse covered in a dust magnet is... not ideal

The other problem is it's extremely difficult to remove and impossible to work on a board if it's coated in this stuff.
 
Short update:

All socketed chips removed yesterday (total 43) and PCBs cleaned. Took partially three rounds for each four PCBs to get them cleaned up. I already did spot some possible problems now when the WD40 is off.

Next target: clean up the removed chips.
 
Half of the chips cleaned. Takes huge amount of time... ~23 chips, nearly 2,5 hours (including two 15 minutes breaks).

Anyway. Two broken traces noted from another A board. Were there for sure before shipped. There was no such damage in the packing materials which could explain this. These traces seem to be connected to up/down buttons and confirmed to be broken with multimeter. I'll get those fixed and most likely the volume control is again functional.

Recapping is needed for at least another A+B set. Some really poor looking caps and leakage marks under a few.
 
"<snack cracle> Houston, we have got the another B board back online, I repeat: another B board back online... Over <cracle>"

Another set of chips washed and installed back. The other B board fired up instantly again.

I believe the problem why B board went to the "green screen" -state was due to dirt and WD40 ruining the connection between eproms/sockets and large connectors between the PCBs.

A good clean-up did not change anything else. Nothing broke more or got any better functionally - even while everything got white spirit, dish (hand wash) soap and water, lot's of water. Sounds are still bad on another A.

Now it's time again to put his aside (too much time used for this project instead of sleeping/having a rest etc.) for the rest of the week. Next week targets: fix the so far spotted trace damages and put a caps order together. CPS2 list should be available online, but I need to get other stuff combined to same order as well.

Because of what broke today (waiting now for spare parts, which will be sent over from France today) at work: next week will be tough though, a big repair job in work right at monday - latest Tuesday, estimated +12 hours (+ lunch time + driving) work day coming... So it might be that I wont be able to do a lot with CPS2 stuff next week. We'll see.

"Over and out"
 
Things are pretty chaotic at the moment, but at least some time poured into this project too:

Last week targets were completed as planned. Two traces fixed (I took pics, but not online yet) and sound volume controls are working again. Nothing else got fixed on sounds. Caps list was collected too. It was pretty different on rev. 6 and 7 than in earlier ones (started building from rev. 3 list I found online).

I collected some other boards (2x Hyper Olympic, one pinball PCB) caps needs etc. late last week and Monday-Tuesday. Components ordered last night. Now it's just waiting that component delivery arrives and then do the caps replacement.
 
Phew... Finally during last three weeks I managed to excavate enough time for this project and finalized caps replacement Tuesday night. Wednesday evening I made tests with boards and the results are:

B-boards still work just fine
Another A board has still the sound issue (actually not surprised here)
Another A board got issue on graphics. Notable stripes from up to down in some screens, in some screens just partial - so stripes are in the background layers. See the three first pictures.

I remembered seeing this issue once earlier before I started cleaning and recapping boards. That time it went off after taking PCBs apart and back together few times. I tried same, didn't help. Removed ROMs and put them back, changed another B-board... No help again. Took a look if some of the caps was wrong way - nope. Nothing seemed to help and I had to leave getting other things done (pretty much feeling angry, frustrated and somewhat depressed at this point)... Later Wednesday night I took another round with the PCB as I remembered that I noted one suspicious looking trace underside the PCB when I replaced the caps. It still looked bad, with microscope it looked totalled from about 2mm length. Tried out with multimeter and no connection. Decided to put jump wire in this time as the trace was quite thing and there were clear through holes in both ends. Damaged area (in last pic, just between the two circles, next to CCCX text) and jump wire in last two pics. Maybe this helps others with same issue with stripes...

Oh well. I still have the sound issue. If someone has good idea what to try/look at, please tell.
 

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stt1 said:
Oh well. I still have the sound issue. If someone has good idea what to try/look at, please tell.
Click to expand...
I have repaired a ton of CPS2 boards over the past 6 months and a lot of them had bad TTL chips. If Hitachi branded there's not much to worry about but the other brands are really not reliable.
A logic probe is enough as they either fail in a way outputs get stuck or completely floating.
 
So, the SMD ones just next to sound area? I remember seeing some 74LS04 and such there.

I had some suspect on them, but didn't want to say it directly, just see if someone raises those up...
 
stt1 said:
So, the SMD ones just next to sound area? I remember seeing some 74LS04 and such there.

I had some suspect on them, but didn't want to say it directly, just see if someone raises those up...
Click to expand...
stt1 said:
Did you encounter something similar as the sounds in this video?

http://kameli.net/~stt/CPS2_Sound_issue_PCBs/VID_20200910_231340264.mp4
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Yes.
From my notes, with garbled sound issues I replaced a lot of the LS374s @2N, 2P, 2R, etc. All TI branded.
 
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