Pc engine duo jumper wires help

I recently purchased a pc engine duo with sound issues from ebay. I just opened it up today with the hopes to repair and the fool had cut all of the jumper wires. Apparently it has had a partial capacitor replacement and seeing as it looks like crap I will be going back over it and replacing everything with nichicons. Anyhow I have taken pictures of the cut wires with the hopes that someone can show me where they were originally linked.

I fixed the one grounding the cd drive as it was self explanatory.

 

Those cut wires were soldered to the shielding plate. My console doesn't have a wire near the heat sink but it does have one coming out from the power plug on the smaller PCB where the DC jack is.

 

@BuffaloWing You don't the wire by the regulator or the dead bugged ceramic capacitor that appears to be hooked to the shielding is some consoles. I'm still waiting on my av cable and psu. Do you think I should hook the other leg of the cap to the ground plane of the main board or just remove both the white wire and the cap? Also thank you so much for the help. You are awesome.

 

It seems like there are multiple revisions of this console. I did a google search and it look like your system resemble this one:

(http://8bitplus.co.uk/wp-content/gallery/pc-engine-duo/PC_Engine_Due_motherboard.jpg)


Notice this version has a 2-pin power connector on the DC jack PCB, whereas mine has 3-pin connector where the black wire goes to the plate. It appears the 2-pin version hooks the ceramic capacitor to the plate. It's probably soldered on the back side, unfortunately I really can't tell by looking at the picture. Does the other end of the ceramic capacitor soldered to the ground plane on the smaller PCB?

I'm starting to think the wire coming out near the heat sink/regulator on your system may be a wire tie (not connected to anything at all). Notice on my system I have ceramic capacitor near the spindle of the CD and it was used to hold down the wire bundle. On the picture posted above, you can see a blue wire loop holding down the wire bundle at the same location and there seems to be another one near the heat sink like yours. Check to see if that cut wire next to the heat sink/regulator is soldered to the ground plane.

 

It is solder to the ground plane. I think you are right that it used as a tie down. The leg of the ceramic cap is hooked to the pin that connects to the red wire of the power jack board. Our white wires on the cd drive are connected the same. It's a shame I didn't receive the shielding. Hopefully I don't really need it.

 

Assuming your ceramic capacitor is soldered correctly (from factory), then you could potentially jumper a wire from the other leg to the white wire and also jumper another wire to the ground plane to ensure everything is properly grounded.

 

I'll definitely do that. The only thing that boggles me is why is both the black and white wire connected to the cd drive? They both go to ground plane and the both connect to the metal chassis of the drive. Also one last question: Why is there unused ribbon cable connections? Specifically there are 6 around the side with the drive and only 3 are used.

 

For redundancy? I'm not sure. As for the extra sockets, I'd like to know too. Perhaps they were meant as diagnostic connection for servicing. Or they were expansion for other features that were never implemented?

 

@BuffaloWing Thank you so much for you help i have brought the pc engine duo back to life. I am doing a full restoration. I fully disassembled the shell and greased(lithium) all of the buttons and sliding bits. I found the previous owner had not removed any of the corrosion when they did a partial cap replacement. It look hours to clean every bit of it of, but luckily all traces were intact though it has missing solder mask where the caps leaked the worst. The previous owner attempted a jail bar fix by removing c923 and replacing it with and electrolytic capacitor and also removing c908. A proper jail bar fix has been installed. And yes redbook audio works now.

Plans now are to finish the rgb mod and do a region mod. I'm using the gametech region board and a voultar rgb board.

 

Congrats on the restoration. PC-Engines are really interesting hardware. I found myself collecting many different variants over the years and never got sick of them. I also need to do some RGB add-on on some of my systems. I plan to do them a little different from others and it's going take me while.

 

Update I was wrong, redbook audio doesn’t work. After I recapped the system more audio started coming in. I got a new hop m3 drive coming and some of the compatible Texas Instruments RC4558D op amps as well. The previous owner had solder to the op amp (ic506) behind the av port as he had left stalagmites for me. I’m planning to hit this issue from all angles. I did a little blind tweaking of the pots to no avail so I’m taking things to the extreme.