MV4FT2 Audio Issues with CMVS.

Dinodoedoe

Bub & Bob's Bub,
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I'm converting my MV4FT2 and I have a beautiful picture but no audio...

I am sharing ground across my component and audio. Is this the issue?

Any suggestions?
 
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Dinodoedoe

Bub & Bob's Bub,
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IMG_8965.jpg

(The wires are NOT connected in this photo)

I had the audio wire connecting to the PCB soldering points off of the L & 10 pins. Then I soldered the wired directly onto the jamma connector. Still nada.

IMG_8966.jpg

I am sharing the ground off of my power supply. Should I actually run wires from Pin 11?

There's got to be something simple I'm overlooking.
 

Xian Xi

JammaNationX,
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First thing is you need to solder to the headphone jack for stereo, then you need to join the two +5v rails. The sound section is powered by the secondary +5v rail via the LM7805 which converts the +12v into +5v. The easiest way to do the mod is by joining the two rails via something easy. I usually do it via the YM2610 as it has pins connected to both rails.
 

Dinodoedoe

Bub & Bob's Bub,
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First thing is you need to solder to the headphone jack for stereo, then you need to join the two +5v rails. The sound section is powered by the secondary +5v rail via the LM7805 which converts the +12v into +5v. The easiest way to do the mod is by joining the two rails via something easy. I usually do it via the YM2610 as it has pins connected to both rails.

One problem, I don't think this board actually has a headphone jack. I was able to get sound from the speaker slider, but it is real faint, causing me to raise the volume on my tv to hear at a reasonable level.

Also, I found the YM2610 chip but I am unable to locate the LM7805 chip. :confused:

IMG_8970.jpg

IMG_8968.jpg

IMG_8969.jpg
 

Xian Xi

JammaNationX,
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The headphone jack is the 4 pin header.

As for the 7805, looks like it doesn't use one which makes it easier. Just tap it from the headphone jack. Pin 1 is left, 2&3 is ground and 4 is right iirc.
 
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Dinodoedoe

Bub & Bob's Bub,
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The headphone jack is the 4 pin header.

As for the 7805, looks like it doesn't use one which makes it easier. Just tap it from the headphone jack. Pin 1 is left, 2&3 is ground and 4 is right iirc.

So I got the audio to work. (Thanks!) It's nice and loud, but now I'm running into a weird issue.

The picture and audio is nice and clean then after about 5-10 mins, I start to hear a whine and the image begins to get wavy in the background. If I turn down the volume on the board, the whine is the only thing you'll hear. Any thoughts?
 

Xian Xi

JammaNationX,
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Power supply looks strong enough, I'm thinking it could be a bad Mylar cap. I once got these same issues with a slight whine but this really distorted picture that would happen if the audio was plugged in but when I unplugged the audio it would go nuts. Then I found out it was one of the Mylar caps(square chicklet looking ones).
 

Dinodoedoe

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Is there anyway I can test the caps or should I just order and replace?
 

Xian Xi

JammaNationX,
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Due to their age, even though some are still good, I'd just replace them all to avoid a headache in the future if you decide to use it in a cab.
 

Dinodoedoe

Bub & Bob's Bub,
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Resolution: I recapped all the audio side of my 4 slot and sadly I'm having the same issues. I was moving cables around when I touched the power supply to my CMVS and I noticed it was very hot. After I replaced the AC power adapter the problem went away. So far I've been playing my CMVS for a few hours and the power supply is cool to the touch and the audio/video has been stable. So it looks like my power supply was faulty from the get go.
 
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