No sound on Puyo Puyo or Final Fight boards

So I got some boards in the mail that I knew would be problematic. For Final Fight I see that there are suicide batteries, but is there a suicide battery that will ONLY kill sound on a CPS1? Or does the entire board die?

Also I see Puyo Puyo is a Sega System C-2 board...any ideas on how to fix the sound? I see that the sound chip on it is the same as a genesis, a) how likely is it that the sound chip is dead instead of something else? and, b) if it is most likely the sound chip, can I swap one out from a Genesis?

Thanks guys.

I don't believe Final Fight uses a suicide battery, however you can easily verify if the battery is working or not with a multimeter.

The easiest way to check if the sound chip is working or not is to get the datasheet for it and use a logic probe on its pins. $15-$20 should get you a decent one.

An easy way to check if the power amplifier on a board is working is to run your fingers over its solder joints.

I don't believe CPS1 uses -5v, but do you have -5v connected? That may be the problem with the Sega board.

Hewitson said:

I don't believe Final Fight uses a suicide battery, however you can easily verify if the battery is working or not with a multimeter.

The easiest way to check if the sound chip is working or not is to get the datasheet for it and use a logic probe on its pins. $15-$20 should get you a decent one.

An easy way to check if the power amplifier on a board is working is to run your fingers over its solder joints.

I don't believe CPS1 uses -5v, but do you have -5v connected? That may be the problem with the Sega board.

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Can you describe (really roughly is fine) how to use the logic probe on the pins to check the sound chip? I've never used one before. I can handle a soldering iron and a multimeter so I can probably handle it.

If the power amp is not working wouldn't video be broken too?

And I do have -5v connected, unfortunately it's not as simple a problem as that (I bought the boards hoping that they only needed -5v).

I have an ESWAT and a Pitfighter, as soon as they are turned on the LEDs on them flash, and then the board dies. Is this a power issue on the board of some kind?

You connect the logic probe to a +5v and a ground point either on the board or the power supply. Then simply touch it onto a pin and it will tell you if that pin is HIGH (+5v), LOW (grounded) or floating.

The power amplifier has nothing to do with video. It is a high power amplifier for audio use only.

Regarding the Pit Fighter & ESWAT boards, is your PSU still outputting voltage when they cut out?

Hewitson said:

You connect the logic probe to a +5v and a ground point either on the board or the power supply. Then simply touch it onto a pin and it will tell you if that pin is HIGH (+5v), LOW (grounded) or floating.

The power amplifier has nothing to do with video. It is a high power amplifier for audio use only.

Regarding the Pit Fighter & ESWAT boards, is your PSU still outputting voltage when they cut out?

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No, my supergun has a PC power supply and a bright LED I installed, and when they cut out, the fan on the Power Supply and the LED both die too, not sure what this means exactly?

Also I got a clue from the seller. He apparently plugged them into his MVS cabinet! I know that MVS mobo's get their Audio destroyed when plugged into straight JAMMA because of pin differences, right? So did this guy plugging these boards into his MVS cab destroy all my audio? If so, what's the next step for fixing them?

I have the following boards with destroyed audio but working video: Final Fight, MK1, and Puyo Puyo.

Pit Fighter, MK2, and Eswat all are completely dead after briefly lighting up (but never enough to output video, just LEDs on the board...)

With the logic probe, floating on the pin would indicate that it's not getting power at all aka Damaged, and the other two are good signs right?

Also I checked my Genesis to see if I could switch the Yamaha sound processor into my Sega C-2 that Puyo Puyo uses...but the Puyo Puyo Yamaha chip is a YM3438, and the one in my Genesis Model 1 is a YM2612...they both have the same number of pins though?

Sounds like you have a short or you are pulling too much current from the power supply.

You say you are using a PC power supply. Is this one that also has a 3.3v output? Some supplies don't like to work without having a minimum current load on the 3.3 and 5v outputs. It can be dangerous to run a PC power supply without the proper loads as switching power supplies can self destruct without it. Most have loads on the +12v lines as well as the -5/-12 already.

If you aren't getting sounds then you should check for +12v at the board as it's needed to run the final audio amplifier. Do you have a multimeter?

I've never seen a Final Fight that required a suicide battery. Sounds to me like someone converted a different CPS-1 game board to it or replaced a bad C board with a different one.

RJ

I do have a multimeter, but it's almost 100% sure to be the boards having bad sound instead of my setup being wrong, because the guy who sold them to me put them in his MVS and probably broke the sound that way, and I also get sound and picture working fine on games that I know to be working (Xmen vs SF etc).

So I am sure the boards are fried somehow and it's not my power supply that's the problem... Thanks for the help guys...

First thing to try if you want to try to fix them is to replace the caps that connect between the audio amplifier chip and the JAMMA connector. Follow the JAMMA pins for audio back to the chip and replace any electrolytic caps between the 2.

If you need someone to repair your boards give me a shout. I do that kind of service.

RJ

Before doing that, have you tried running your finger over the solder points on the power amplifier to verify that it is working?

If plugging them into the MVS harness has damaged them in any way, itll be the amplifier that has gone.

Hewitson said:

Before doing that, have you tried running your finger over the solder points on the power amplifier to verify that it is working?

If plugging them into the MVS harness has damaged them in any way, itll be the amplifier that has gone.

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I respectfully disagree.

If the caps between the amp IC and the JAMMA connector are bad then running your finger over the amp chip will have no effect. Those caps are cheaper and easier to replace than the amp IC and can be damaged if you are plugging into an MVS wired cab.

They should be your first item to replace rather than the more expensive amplifier IC.

Hewitson said:

Before doing that, have you tried running your finger over the solder points on the power amplifier to verify that it is working?

If plugging them into the MVS harness has damaged them in any way, itll be the amplifier that has gone.

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What does the amp look like on the board? I know what caps look like but I am not sure what the amp is, and am I supposed to feel a tingle or something if it's working?

I would LOVE for it to be blown caps, cus I could swap those out myself easily...

The amp chip is the one that has the heatsink attached.