Jamma board - no sound -

[CICA2]

I have a Street Fighter II arcade game with a Jamma board.
The seller said that the sound works intermittently for some reason.

I've done some screen repairs on it and cosmetic work on the cabinet. The only thing remaining is the sound. While working on it I only heard sound once, right after I turned it on "allllyouuukin!!!" Nothing after or before.

I checked the wiring; tried different speakers; checked if the board receives 5V and 12V; checked the volume pot: 2.05K ohms; Everything ok.

I noticed that some of the orange jumper casings were broken, as shown in the pictures below. I believe these are jumpers (could be wrong) because they have continuity. I checked if any of them crossed, they do not.

What should I check next?

[spacies]

Could be a dud sound chip/CPU?

*edit*

*edit*

Process of elimination my friend.

[Malenko]

this probably isn't the reply you are looking for but.....


just get a new SFII board. They are cheap and easy to find, even better upgrade the cab to a CPS2 system, then you can play everything from Super SFII Turbo to Dark Stalkers 3

[BobA]

Jumpers should have continuity.  They are just a piece of wire and insulation.

[CICA2]

You are right, not quite the answers I was hoping for.

I was hoping to hear about a root cause for intermitent sound problem from someone who had a similar problem. 

Process of elimination works great when I have spare parts. Unfortunately it is less practical when I have to order in each component and buy them. It may come to it, if I don't have other choices.

oh, I read somewhere that jamma pins M and 11 labelled as N.C. are actually unamplified audio signals. I think I'll try feeding these into my stereo and see if there is sound. If there isn't, at least I can eliminate the amp from the list of possibilities.

 

[grantspain]

i hope i am not being stupid but where is the rest of the game board,like the top board?

[BobA]

Did you say if the picture is OK?    Grantspain it pointing out that the SFII board is really a 2 board set.  Your picture shows only the bottom board.

[CICA2]

yes the pictures posted above do not include the cpu because I could not find any visible damage on them.

And yes the video, gameplay... everything  is perfect now that I changed the hot, bunch of caps, and the flyback on the video board.

Here is the complete set of the circuit boards.

[modessitt]

I checked the wiring; tried different speakers; checked if the board receives 5V and 12V; checked the volume pot: 2.05K ohms; Everything ok.

Is this +5V and +12V?  According to the Street Fighter II conversion manual, troubleshooting a sound problem mentions verifying both the +12V and -5V are present to the PCB.  this is strange because further in the manual they show the JAMMA pinout and don't include the -5V.  I don't know if it is required or not, but I know some JAMMA setups don't use the -5V so yours might be missing the wire or not hooked up - if it's needed at all.

This game doesn't use an on-screen menu with volume settings does it?  I know there is a dip-switch to shut the sounds off in attract mode, but that shouldn't affect the game play sounds...

[modessitt]

Just thought of something.  the Jamma outputs sound to both left and right speakers.  Some games don't have stereo sound and output everything on only one line.  If you only have one speaker, try changing it to the other speaker signal.  If you have two, check to make sure they aren't both tied to the same output....

[CICA2]

Yes it is +5V and +12V. And I also found mention of the -5V in the trouble shooting guide but as you said, the Jamma pinout does not include -5V, so I dismissed it being a misprint.
If it needs the -5V, the wire from the power supply is currently missing and I have no idea where to connect it on the circuit board.

I don't think the game uses an on-screen menu. If it does, I haven't been able to access it. I tried holding down P1 and P2 when turning the game on, but there is no menu.   

The game is mono. The cabinet is equipped with two speakers, but both go to the same output on the Jamma board.
I tried disconnecting the speakers and hooking up another test speaker...no sound.

I am assuming that the chip mounted on heat sink is the sound driver. Anyone know if it can be tested?

[CICA2]

oh, I read somewhere that jamma pins M and 11 labelled as N.C. are actually unamplified audio signals. I think I'll try feeding these into my stereo and see if there is sound. If there isn't, at least I can eliminate the amp from the list of possibilities.

I tried this. All I get is a solid HUMMMMMMMMMMMMM out of my stereo, damm.

Any ideas of what else I can try?