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

[mouth78]

I am here again. Finaly i found a very,very small track Broken and repaired It. Duo start whith system card 3 and hu card works ok. But CD doesnt spin... When I use CD, len cames to the center, go up and go down 4 times and stop...I can see red laser into the len if I dont use a CDrom.

What can I do?

Note: Motor is ok, if I conect 3V to the motor, motor spins

Thanks a lot.

[Keith Courage]

The lens moving to the center and moving up and down is good, but the disc should then spin up. Have you tested another lens after you repaired the bad trace?

[mouth78]

Hi Kevin. I haven't tested another lens...