What's new
By:

CPS2 sound issues

stt1

stt1

Professional
Joined
Nov 29, 2016
Messages
456
Reaction score
426
Location
Pornainen, Finland
Not exactly a multi-issue yet, but the end target is getting two working CPS2 multi-setups, another for me and another for my friend (a member on this forum as well). I'm trying to get the PCB sets working before ordering/applying any multikit.

So, the saga of broken CPS2 hardware continues (earlier happened: two battery acid destroyed B boards, two A boards not booting up correctly).


Recently I got two sets of A+B boards. By sales terms they should have been fully working, but another set proved to have bad sounds (sounds have a lot of distortion and kind of playing just wrong parts, also some tunes tend to jam playing constantly).

So far done:

  • Jumpers on B boards checked to be good (Excel table here used for checking)
  • Swapped the B boards between A boards, faulty sounds keep on same A board -> ROM failure on B board not likely
  • Tested once more on the 'good' A board -> both games have good sounds
  • Tested once more on the 'bad' A board -> both games have bad sounds
  • Memory test goes through without errors on the 'bad' A board
  • Noted that on 'bad' A board it's not possible to change the sound volume. It stays same when I press (SW2/3) buttons near jamma connector
  • Googled up for CPS2 sound issues, but didn't find exactly similar issue and solution for it so far


Looks like an hardware problem on the A board. Does anyone have a good guess or straight answer what/where I should be looking?

I took high resolution close up pics today from both PCB sets, feel free to take a look if there is something you can spot... Yes, there is dirt, I haven't cleaned them yet. They are in same condition as seller sent them to me. Link below:

http://www.kameli.net/~stt/CPS2_Sound_issue_PCBs/

When you want to see the picture in full size, click the picture open and click "Actual size" button or open the picture in new browser tab.
 
If the Z80 is socketed you can try swapping it from the known good board. It's a likely candidate for going bad.
You can reset the volume by holding either volume up or down while starting the board (one or the other, I can't remember which). It should take care of volume issues (silent, too loud, etc).
 
Apocalypse said:
stt1 said:
  • Noted that on 'bad' A board it's not possible to change the sound volume. It stays same when I press (SW2/3) buttons near jamma connector
Click to expand...
Could it be the volume controller?
Click to expand...
Possible, which components are handling this? The Z80 as ic3b4ll suggested?

ic3b4ll said:
If the Z80 is socketed you can try swapping it from the known good board. It's a likely candidate for going bad.
You can reset the volume by holding either volume up or down while starting the board (one or the other, I can't remember which). It should take care of volume issues (silent, too loud, etc).
Click to expand...
Not socketed, but I can get a socket soldered there. Need to order more parts though, so takes some time to try that.

There is no issue of being silent or too loud. It's just bad quality/wrong sounding/distorded (such a lot that while game is playable, it can not be enjoyed). Tried to turn volume down from settings, but seems to be stuck on same level. I can try resetting the volume late tonight after work day etc.
 
stt1 said:
There is no issue of being silent or too loud. It's just bad quality/wrong sounding/distorded (such a lot that while game is playable, it can not be enjoyed). Tried to turn volume down from settings, but seems to be stuck on same level. I can try resetting the volume late tonight after work day etc.
Click to expand...
My "hold button at boot" suggestion was to get the volume unstuck. Try it, it's a somewhat common issue, but it's usually stuck at zero or at full volume, so it may or may not work.

If you could make a video of the sound issues (erm) it would help pin down the issue. The sound part comprises a lot of different digital and analog parts and what you call 'distorted' some people call 'dubstep' or 'death metal' :D
 
Yeah, will try your suggestion.

Can do the video as well... Don't know how to describe it very well. I would say something like interesting and disturbing at same time. :D

I'll have time for both, after about 3-5 hours from now.
 
ic3b4ll said:
stt1 said:
There is no issue of being silent or too loud. It's just bad quality/wrong sounding/distorded (such a lot that while game is playable, it can not be enjoyed). Tried to turn volume down from settings, but seems to be stuck on same level. I can try resetting the volume late tonight after work day etc.
Click to expand...
My "hold button at boot" suggestion was to get the volume unstuck. Try it, it's a somewhat common issue, but it's usually stuck at zero or at full volume, so it may or may not work.
If you could make a video of the sound issues (erm) it would help pin down the issue. The sound part comprises a lot of different digital and analog parts and what you call 'distorted' some people call 'dubstep' or 'death metal' :D
Click to expand...
Video here:

http://www.kameli.net/~stt/CPS2_Sound_issue_PCBs/VID_20200910_231340264.mp4

Tried holding buttons (one at each time) during boot. Nothing happened. Sound volume still at 16 and can not be changed.

Need to measure if up/down buttons are actually working.
 
Raph_friend said:
This issue has nothing to do about volume, it's a decoding one. It still happen when you swap B board?
Click to expand...
Yes, both B boards have bad sounds when used with this A board.

And yes, bad sounds are not due to volume control.

However, there is also another problem that volume controls don't work (changing volume level is not possible).
 
Raph_friend said:
On my article i explain why most of times switch won't work, just like sound decoding. Won't be a simple fix.
Click to expand...
I agree, it won't be simple and that it seems like an address decoding issue - the board is playing an instrument or sound effect correctly but in the wrong place.
Do you have a logic probe? It will make finding the fault a lot easier.
If you do, try probing the address lines to the sound MaskROMs on the B board. You'll likely find a stuck address line and from there you can figure out where the issue lies.

 
Last edited:
Thanks for confirming my fears. "This wont be simple..." was my first thought when I heard the sounds.

No, unfortunately no logic probe. Neither oscilloscope (has been a while on buy-list).


And this keeps giving. Another B board just gave up. It's only giving solid color (green or turquoise) when I try to boot with it. Tried with both A boards and it's same. Connector pins looks good.

Time to clean up. Even if there are visibly broken traces or cracked solderings, I can't see them under the layer of oil and dirt.
 
Following this thread as I have sound issues as well. Keep me posted!
 
May be a long wait, sorry. One reason for buying "fully working" set was to avoid doing this kind of repair. :(

While I might be able to repair this after all, I really don't have much time for this at least coming weeks. Next week target is a proper clean up (getting rid of WD40 and dirt). In a very good case, some base visual checking and measuring might also happen.
 
Maybe it’s confusion, there’s a WD40 product safe for PCB use called “Specialist Electrical Cleaner Contact Spray”, however some may think the degreaser is the same thing.
 
djsheep said:
Maybe it’s confusion, there’s a WD40 product safe for PCB use called “Specialist Electrical Cleaner Contact Spray”, however some may think the degreaser is the same thing.
Click to expand...
Don't use the contact cleaner spray to clean boards though... It will leave the board full of white stains because it will dissolve the flux residue so you'll have to wash it again.
It's great to remove stickers though.

Isopropyl alcohol does pretty much the same and it's a lot cheaper.

WD40 makes the boards look really shiny and nice and I can understand why one would like that look. AND it smells delicious when you use hot air to remove something on a board soaked in it. Hmmm... Fried something...
 
ic3b4ll said:
Don't use the contact cleaner spray to clean boards though... It will leave the board full of white stains because it will dissolve the flux residue so you'll have to wash it again.It's great to remove stickers though.

Isopropyl alcohol does pretty much the same and it's a lot cheaper.

WD40 makes the boards look really shiny and nice and I can understand why one would like that look. AND it smells delicious when you use hot air to remove something on a board soaked in it. Hmmm... Fried something...
Click to expand...
STOP PLEASE!
 
You must log in or register to reply here.
Back
Top