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

[thesteve]

the 3.3 is a common failure part
nobody changes the BRAM cap

[ConHuevos]

Hi everyone, just joined this forum because my Turbo Duo had extremely low audio.  I decided I'd replace the caps and ordered a whole batch of 105C caps off of Digikey.  I'm no stranger to soldering, but this is my first time replacing capacitors.  Could someone please explain to me how to know which end gets soldered where (+/-)?  Thanks.

I've already taken several closeup pictures of my Duo's motherboard before pulling the caps so I'll know exactly where everything was, and just pulled them all yesterday:






The red circled areas had leaked all over and it smelled like bad fish when I took some of the caps off in those areas.  Some of the electrolyte fluid had corroded a couple of the solder pads, but I was able to clean some of it and salvage the pads (thank goodness)!  The parts should be here around Tuesday and hopefully I can start then.  So ya, if someone could help me on the +/- guidance for the caps, I'd appreciate it, thanks!

[BlueBMW]

On the cap replacement chart at the beginning of this thread, the black side is the negative side.  Typically on the board they're marked with either white around the hole (for through mount caps) or the flat squared side of the SMT shape printed on the board.

[ConHuevos]

Ok thanks, and I'm correct in assuming that the longer lead on the capacitors is negative?

[BlueBMW]

Ok thanks, and I'm correct in assuming that the longer lead on the capacitors is negative?

The sides of the capacitors housing should be marked with a line or bar indicating which side is negative.

[gilao]

I have a Turbo Duo and was without sound, the sound was very low even changed all the capacitors, now the Hu Card games have sound normal, but the games on CD still has very low sound, have to increase the TV volume at most and is still down, anyone know what can be ? Thank´s.

[ConHuevos]

Quick question...I don't see the location of the 3.3uF 50V capacitor anywhere on the diagram.  Where does that one go?

[thesteve]

3.3 is under the cd drive wires

[ConHuevos]

Got it, just replaced all my caps and sound is working 100% on hucards and cd games again:



Now my CD drive doesn't spin up though.  The laser is still powered and tries to read the disc, but it doesn't spin.  I'm hoping I just forgot to plug something in but what could that be?  It worked perfectly fine before I did this.

EDIT:

Nevermind, I had the CD wires in the way, also forgot the disc won't spin unless the laser detects the disc first.  Works great now!  Another Turbo Duo saved from the capacitor leak issue!

[HercTNT]

Stories like this bring tears to my eyes. Another success story from the Pcenginefx STTF "Save The Turbo Foundation".

[Necromancer]

Another Duo saved to OBEY another day!  Well done, ConHuevos. 

[ConHuevos]

Ok, today I noticed something that isn't normal.  I'm only getting audio from one channel.  My white audio plug has no audio coming out of the duo, via hucard or CD-ROM.

Any idea what can cause this?

I hope it's something simple I overlooked.  Worst case scenario...how much would it cost to have this repaired by one of the board members?

[thesteve]

could be your AV cable

[ConHuevos]

could be your AV cable

As much as I would like it to be, I don't think it is =/.

[BlueBMW]

If its not your AV cables, then its probably a corroded via or trace caused by the leaked cap fluid.  Did you clean the board really well before you put the new caps in?