REPAIR GUIDE - TurboDuo/PC Engine Duo: Total capacitor replacement chart

[ConHuevos]

I tried my best with alcohol, the back of the board is covered in yellowish liquid I tried to clean off.  2 of my solder pads were somewhat messed up but I managed to salvage them.

[BlueBMW]

On this duo, I had no sound even after a cap swap.  Look at the black crud around one of the via holes.  A through cleaning then testing of continuity and repair of some of the vias was necessary.

[ConHuevos]

Via?

[BlueBMW]

Vias are the little holes in the board that make connections from one side of the board to the other.

[thesteve]

the via's are often bare copper plated, making them easily corroded.
a wire strand through the hole and soldered up fixes them

[ConHuevos]

Blue, how much would it cost to ship to you and fix the sound?  This is my spare duo, but playing order of the griffon with only 1 sound channel annoys me so much .

[NightWolve]

Randomly found this today, so for possible useful reference:

"PC Engine Duo/Turbo Duo Capacitor Replacement Set"

Cost: $9.99

http://gamedoctorhk.com/index.php?main_page=product_info&products_id=1143



They've got NEC parts/games, laser units for DUO-R/DUO-RX, etc. Anyway, might be useful for someone though I think if I ever do this for my Duo when it breaks, I'm gonna try to buy tantalums this time instead (unlike my TE).

[ConHuevos]

Ya, I saw that when I went to replace mine.  But then I noticed they are from China, and really didn't wanna trust the quality of capacitors they're getting.  Besides, for $2 more I got all hi temp caps from digikey so I had piece of mind and knew they were from a good brand, not cheap Chinese junk (not saying that's what it is, but it may be).

Shout outs to thesteve for fixing my sound issue, fixed it the day it arrived at his door.  Thanks!

[SNKNostalgia]

Well, stayed up all damn night trying to fix the right (red) sound channel and I still get no sound at all. It was actually extremely low volume before I did the entire cap replacement. I tested the AV out on the side and the headphone jack. I am seriously out of ideas.

I also managed to lift a few traces, but was able to get a connection through the Vias (copper holes). I also have to redo the region mod connection, as it is a complete bitch to get to the lower cut pins and solder wires off the HuCard slot. Sighhhh...

Anybody know the full trace route for the right sound channel from beginning to end?

[SNKNostalgia]

  Well, spent a good 12 hours today trying to fix my Duo and this shit is hopeless. When I unhook the region mod entirely the system boots to CD start menu but the disc drive is just flat out dead. When I wire-up the region mod the system is stuck on a light blue screen no matter what.

I. am. screwed!!!

Anybody want to have a go with it? I am considering sending it off to get fixed. If it doesn't come back to life, then I guess I can scrap it. I definitely would like to keep the grahf made region mod board in the long run. The newer and easier S-video mod will more than suffice now that the knowledge is out.

[thesteve]

the blue screen means you have a wire crossed on the mod.
not sure why your cd drive is dead

[Charlie]

=>>Anybody know the full trace route for the right sound channel from beginning to end?<==

What, abbreviated schematics and technical descriptions aren't enough?  We have a lot of these here, about many of these consoles.
Try a seach for "Duo" and "schematic"....I'm pretty sure that there are numerous threads here about this, and many of them lead to other threads.  There may even be one actually related to the DUO and it's audio.

Good luck.

Charlie

[BlueBMW]

=>>Anybody know the full trace route for the right sound channel from beginning to end?<==

What, abbreviated schematics and technical descriptions aren't enough?  We have a lot of these here, about many of these consoles.
Try a seach for "Duo" and "schematic"....I'm pretty sure that there are numerous threads here about this, and many of them lead to other threads.  There may even be one actually related to the DUO and it's audio.

Good luck.

Charlie

I was just looking at that schematic the other day...  its there SNK, just search for it.  I'm pretty sure Charlie posted it.

[thesteve]

remember its not a full schematic, but it should get you in the ball park.
as a side note check the voltages on the caps by the EVC chip (SIP behind the heatsinks)

[SNKNostalgia]

I wondering if the 470uf just above the heatsinks is the culprit. It is possible I slightly overheated it with the solder iron. It was a big pain to get out due to the wires being bent when originally installed. My multimeter display shows random garbage unless I mash the screen in a little, so this will be fun.

Any tips on soldering to the hucard slot pins? I feel like a I am playing a game of operation that is 10x as hard. I am roughly intermediate to advance at soldering over the years, but not quite the expert. Maybe if I were to take some sort sniper tranquilizer, lol.