No Audio on MV1-C (large pics)

[jeffslot]

Hi guys,

My video is working great (RGB on PSONE), even my d-pad is AOK. I can't seem to get my audio going though (I had John_Smith do the +5 volt Audio mod for me - & it looks like he did a fine job). Any suggestions will be helpfull.

Mv1-C

By classicvideogame at 2008-10-26

Back of psone screen

By classicvideogame, shot with Canon PowerShot S400 at 2008-10-26

 

[Xian Xi]

Why is the cap next to the sound chip cut off? I'm certain that needs to be there.

 

[jeffslot]

Hi, it is there, it is just on the other side of the board (same location). 'It was moved' to flatten the board.

 

[Xian Xi]

You sure it's in the right way? What's that white wire going to the back?

 

[jeffslot]

I was pretty carefully when doing this part of the mod. But I'll tell you what, I really want the sound to work, so I will put the cap back the right way & see what happens. Shouldn't take too long.

Jeff

 

[Xian Xi]

Also why is there a resistor missing above the chip?

On the PSOne screen, if you hook up the RGB lines to the monitor don't you also need to connect the audio to AUDIO L and R and not EXT? I thought some one said that before on another forum but I could be wrong.

Also keep in mind since there was a lot of soldering very close to the chip, depending on heat the chip could have fried.

 

[jeffslot]

If you dont' see a resister it isn't missing, but just re-located to the other side of the board. I did move that cap back, didn't seem to make any difference.

 

[MKL]

If you dont' see a resister it isn't missing, but just re-located to the other side of the board.

I don't see how that is possible (let alone why it was done): that's the serial data line to pin 6 of the DAC coming from pin 59 of GA3. It runs on parts side only, thare are no vias, just the 33ohm resistor in series with this line. From the pic I just see a small piece of wire seemingly bridging the sides of the resistor. Now I really want to see what this relocated resistor is doing.

 

[jeffslot]

Hi,

I hope we are talking about where it says AC3 on the board. There was a cap there, that I relocated to the other side of the board to flatten it. I ended up using 1 wire on each side of the board, but have since returned it back to the parts side as mentioned by xian_xi. Is that what we are talking about? I'd love to clarify if that isn't what we are talking about. Thanks for your help.

Jeff

 

[MKL]

I'm talking about this:



There was a 33 ohm surface-mount resistor across A and B (like those other two at the sides) now replaced by a small piece of wire joining A and B. I don't see why this was done. Perhaps because the resistor was damaged by mistake? Anyway check if you have continuity from pin 59 of GA3 (the arrow) to pin 6 of the DAC (9480F). If you do, try hooking up the stereo channels (and ground) to a TV or a stereo receiver instead of that monitor. If you don't get any sound then the DAC probably got damaged by too much tinkering.

 

[MKL]

Another thing that doesn't look right to me is the wires soldered to the capacitor AC2 (upper left corner of 1st pic): where do they go?

 

[jeffslot]

Ah, I see. I actually haven't touched those areas of the board. So I guess it was either that way when I got the board from john_smith or that was part of the mod he performed. It is looking like I'll never get working audio from this board :-( . Video on the other hand looks really good.

Jeff

 

[Xian Xi]

Can you snap some pics of the back of the PCB in the sound section? I don't know who this John_Smith guy is but the mods looks weird.

 

[jeffslot]

Sure, I'll do that later tonight (I've got company now) - thanks again for all of your help.

 

[jeffslot]