Power Supply - Delay Output

[almamater]

Hello everyone, i bought another faulty LG Mini Hifi (to salvage the CDPlayer module for my original LG: here).

But now i just only want to understand what could be wrong with this "other" power supply, nothing visually wrong with it but voltages take a long time to appear at the outputs.

I only found this service manual and at page 37 they show all the Power Supplies variants for this LG Model, and this one doesn´t have StandBy Led, so some transistors are not present.

Initially i didn't had any other voltage beside the +5V output, i replaced one transistor (the Q909 (S8050 NPN)) and then i have other voltages but all with delay.





I checked this components:
IC901 (DM0365RN) -> Testesd it with another one
IC902 (TL431) -> Testesd it with another one
PC901(OPTO) -> Testesd  it with another one

Diodes (D910, D908 and D909)-> All removed and tested, values seems Ok.

THis board have 3 transistors S8050 (Q9009, Q905, Q911) and one B772 (Q908) and replace all with new ones.

Check all the electrolytic capacitors and seems all ok.
 
But voltages don´t appear without the ~2-3 minutes delay but then it works all ok.   

Any idea what can cause the 'delay'?

[wn1fju]

If you are sure all the caps are OK, could there be a cold solder joint somewhere that takes a few minutes as the board heats up?  You could try to reflow all the solder joints on the board.

Otherwise, try to see what voltages are delayed.  Is the controller chip getting Vcc instantly?  Are the primary side voltages coming up fast?  Be extra careful of high voltage on the primary side of a switching supply when poking around - there's enough there to hurt/kill you.  I would try to trace voltages through the schematic before simply randomly trying new parts.