Pc engine duo doesnt power on

[mouth78]

Hi everyone.

I bought a pc engine duo, the owner told me It worked, but It sounded low and then owner decided to do a recap. Owner desoldered all caps but never soldered new ones. He had a caps new kit and he gave me with console.
When I recibed the duo i disassembled it and i saw the board was clean but several pads, potentiometer sound and  switch cd tray was disappeared. I found alternative pads, and soldered new caps and the potentiometer.
My problem is duo doesn't power on ...

I have fusible OK, Diode OK and the two regulators of tension send 5v. What is the next have i check?
I really like revive this console, I think is a nice model.
Any help is welcome.
(Sorry my bad English)

[mouth78]

Some advice?😢

[Keith Courage]

Are you sure there's no power? Remember there's no power light on a duo. the light only turns on when you hit run to start up a CD game.

the vast majority of the time when someone sends me a Duo that says it has no power, it turns out to be a defective AV cable.

[mouth78]

Yes, I know...,,😢 That's not the problem...
I don't know what I must to do...any idea?
I proved all capacitors are in correct position. I have a short in C315, but I remove it and the short continues...I am not sure if is normal...

[Keith Courage]

so is it just a black screen when you go to turn on the system or is it a solid white screen or something along those lines?

Have you checked if the fuse is good?

[mouth78]

My 10V power supply has dead ... Can I use a power supply of 9V or I must to buy new one 10V power supply.

Screen don't show any activity and when I push "run" nothing happens.

Fuse is ok.

Regards.

[mouth78]

Some idea is welcome.

[mouth78]

I have news. I use the 9V power supply. Today I connected earphones and I could ear sound of game...,😱. Sound was very low but I could ear Bomberman.
No signal in my TV...I use AV cable of duo-r. Is Duo-r cable compatible with duo?
Led don't light although I press run button...
I discover IC503 hadn't ground in pin 4, one of the little holes didn't comunícate upper track with lower track, so I soldered a cable to get ground in pin 4 of IC503. Now I get high sound with earphones but I can't get any signal in my tv still ...

[mouth78]

More news:
Today I have used another TV and when I siwtch on the console TV shows a white imagen. If I put hucard game it works perfectly, image and sound perfect ,🤤...I suppose there is a problem with the ROM of system card 3. Where can I search the problem? What do you think about?
Regards.

[Keith Courage]

A white screen for the CD bios in a black DUO could be a number of things. Bad capacitors, a bad voltage 7805 regulator, Corrosion on traces or via holes(usually under the card slot area), a bad cd bios chip, or a bad D91317GD. I'd start by changing out all of the capacitors and testing both 7805 voltage regulators to make sure both are putting out 5V.

[mouth78]

Thank you very much. Do you know how much V every capacitor has? It could be very useful to find a bad capacitor...(I know 22uf capacitors between heat skins and hucard must be about 5V).
I have to test the capacitor and the regulators again.

Regards.

[mouth78]

I have been measuring the tension in each capacitor.
Do you see any strange?
Thanks a lot...
https://ibb.co/zhkxmr4

Note:
I only switch on the console,without games.
All values in V.
C884: 0.92V