MV-1B sound not working

Hi, I have an MV-1B that I got for $5 from an operator who I was buying some games from. He sold it because the audio wasn't working and he said he didn't want to try and fix it because he had a bunch more sitting in storage. After looking around the board I am lead to conclude that the either the main amp or the opamp is probably bad. How can I confirm this, and if it is the amp or opamp that is bad how can I replace it? I was thinking a good test would be to try the stereo mod points and see if it works, but right now all I have done is slap it into a cab and noticed the sound isn't working at all.

Thanks!

Yeah maybe see if you can still get line level out of it.

The no sound question again. Short answer and the most possible explanation to problem are bad caps in the audio section. This is not guaranteed to be the solution because I do not have your board in front of me but has been proven time and time again the likely answer/solution.

OK, how do I test this theory, and what caps will replace the ones already on the board? The current capacitors are very weathered and difficult to read, and if they are bad my meter won't give the right values anyway.

Hit up RJ aka Channelmaniac for an audio cap kit if possible.

Thanks for the props guys.

I don't have a kit for the 1B. I asked him to send me some hi-res pics so I can assemble one.

I'll throw out the same offer I did for monitor cap kits: Help me to build it and I'll give you one.

RJ

Awesome, thanks for the help guys. This 1B is going into a new CMVS I am working on, one with an all wood case. (getting rid of the plastic holder) I am also working with 68k on details for overclocking it for MS2!

I find a nice easy way to test power amplifiers is to run a finger over their solder points. You will hear a crackle from the speakers if its working.

If it is, I'd say your problem is op-amp or caps.

Hewitson said:

I find a nice easy way to test power amplifiers is to run a finger over their solder points. You will hear a crackle from the speakers if its working.

If it is, I'd say your problem is op-amp or caps.

Click to expand...

But...

If you don't hear it, it doesn't mean the amp is bad. You could have bad 470uf caps between the amp and the speakers. Those are the most common caps to go out on a Neo Geo board. Those caps are used to block the DC component of the audio amp's output.

RJ

Alrighty, capacitor pics are now up. I hope to be able to get my cap kit set up soon and report back how things went.

EDIT: for the curious, the pics are here: http://picasaweb.google.com/arf.at.sjv/MV1BRepair?feat=directlink

Don't know how I managed to forget posting that part.