Need help with RGB modded Duo R (Fixed)

[GohanX]

Okay, I've been working on this thing all night, and it's 2 am and I'm cranky.  I'm writing this partially because I need help, and partially because I need to vent or I'll never go to sleep. 

Cliffs notes:

I bought a Duo R with an RGB mod off Ebay.  The RGB looks great, but for some reason I get no right audio channel, although if I hook up the regular AV cables the audio is fine.  It must be a crappy cable.  It turns out, it's not the cable, and the RGB conflicts with the right audio channel.  WTF?

Venting version:

I have all of my other systems hooked up by RGB, except the NES and Duo.  I can do some soldering and modding, but I'm not expert at it and I was afraid I couldn't solder the RGB lines from the video chip, plus I couldn't find a good source for a single DIN8 jack.  So, I bought a pre modded one. The right audio doesn't work, but I figure no biggie, I'll install some RCA jacks to it and pull the audio from there. I installed the audio jacks and a composite video jack (I'll never need the regular AV cable again!) and tested it on my composite-only TV in the back room.  Everything works great, the video is clear, the left and right audio channels are distinct, and I have golden bling on the back of my Duo. Mission accomplished.

I take it to my main tv with component, hook up the RGB cable, and the audio cables to the jacks.  Well... that's where it goes downhill.  Not only does the right audio channel still not work, but I have no green!  This makes no sense.  I hook the composite cable into it, and still no right channel.  But, it was working a few minutes ago!  I then disconnect the RGB cable, and the right channel magically comes back in.  As a side note, the RGB goes completely nuts when you plug the composite cable in, I think they used composite for the sync line.

I open the Duo back up, and see that I somehow managed to disconnect the green wire from the HuC6260 chip.  I actually manage to solder it back into place (confidence +1), test it, and the picture is fine again, but still no right audio.

So, I'm back where I started from.  For some reason, the RGB interferes with the right audio channel, and I don't know why.  It is not the cable, it is something internal.  Help!

[Duo_R]

Do you have a multimeter? I wonder if some pins got jumped on the Hu6260. I know mine did while I was doing my install, and I had to get a magnifying glass and use my meter to confirm that two had in fact jumped. My theory is that 2 were jumped when you got it, your green wire got removed which fixed, but then when you soldered back it got jumped again. Of course I could be completely wrong but worth checking out. Did he drop some glue to strengthen those wires???

[GohanX]

I do have a multimeter, although I haven't broken it out.  There isn't anything holding the wires in place but solder, although dropping some glue on it is a good idea.  Is there any particular kind of glue that I should or shouldn't use?

If I remember from the wiring schematic I found (in french!) the pins beside the green are both ground.  I discovered this the hard way when I was soldering the green pin back, and I kept soldering green and ground together.  I got it right eventually though 

The green shouldn't have anything to do with my problem though, the sound still didn't work even when the green was disconnected.  I think I"m going to use my multimeter to poke around the DIN socket, since that's the only place in the system where the RGB and the audio lines are anywhere near each other.  If nothing else, maybe I can isolate what is conflicting and maybe rewire it or something.

I'll post some pics in a bit, this RGB mod doesn't exactly follow the one on the www.gamesx.com website.

[Duo_R]

post up some pictures of what the mod looks like (that will be interesting). Do you have that french diagram? That would be extremely helpful for me, I want to know more about the board and chipset (and there is little information to be found besides Gamesx.com).

[GohanX]

Here's the link to the page that shows some of the pinout: http://wiki.pcengine.info/pmwiki.php?n=Hardware.HuC6260

I can't seem to get the attachment feature to work, I'll see if I can post it up somewhere tomorrow and link to here.

I managed to fix the problem!  After carefully checking everything on the mainboard and finding it to be perfect I cracked open the little PSX adapter cable again.  On a hunch, I snipped the right audio wire, then plugged it into the Duo. Success!  I assume that maybe the soldered connection on the adapter's DIN plug is grounding or something, but I'm not taking it apart to find out.  Right now I have both glorious component video and sweet stereo sound.  Plus some gold plated bling on the back of the Duo.

The mod in the system was done pretty well, but the PSX adapter cord was a total hackjob.  I don't think they were done by the same person at all.

[GohanX]

Here are the pics of the mod and system.  I couldn't get this forum to upload them, so I'm linking from another forum.

Here is the top part of the motherboard.  The red green and blue wires are obviously RGB, the black is composite sync I think, and the thing wrapped in plastic is the amp.  There is also a yellow wire coming out of the amp that is connected to the underside of the mainboard, I have no idea what it is for, it is not mentioned on the gamesx RGB mod page. The larger wires at the top are going to the AV jacks.  Red is right, green is left, and black is both composite video and ground. I only have three colors of wire.



The bottom:



The exterior-I swapped the cases with my old Duo. The RGB one had some minor scratching, but my old one was nearly perfect. This mod was my first time (well, second, I practiced on a Genesis) drilling into plastic, so it's not as straight as it could be.





By the way, if anyone knows what that yellow wire is for, I'd like to know.  I would guess by the color it has something to do with composite video, but I really have no clue since it doesn't go to one of the chips.

[Duo_R]

The yellow wire is 5+ power for your RGB amp???

[Duo_R]

ok I am positive that is 5+ line, look at the other side of the board where that yellow line is going. That is one of the 7805 type circuits that regulate voltage at 5+. He grabbed it from the bottom of the board because that is easier to access. Can you post a close pic on that yellow wire where it connects?

[Duo_R]

who was the ebay seller u bought that from? did you ever fix? It sounds like the audio that was tapped was incorrectly wired up. Is the issue with the sound coming from the 8din or the RCA's that were mounted? speaking of that, why does it have the 3 RCA's when it already has a 8din port?

I would check that audio wire, something is fishy. Either replace the wire or check the ground connecting to the RCA plug, maybe that went bad. Multimeter is your friend though that would make it easy to find the issue.