Pc-Engine DUO - White Screen - No sound, No Boot, No Bios loaded

[Lunacy]

Hi people,

First i would like to say that this forum is a real informations treasure !
Thanks a lot to people who help other people to find solution about PC engine Console. 

Today i have a problem with a Junk Pc Engine DUO i bought.

When i power on it, there is nothing on the TV, only white screen.
Always white screen, with Hucard, Without Hucard. No sound, no CD-rom BIOS..

I checked continuiting points from IC513/IC513 and IC515 with multimeter > Its OK

I replaced some Caps but always same problem. I check Hucard ports and cleaned it with Propylic alcool then looks good... It's seems no burned points on mainboard or under the HuCard port, i checked it.

My questions are :

> What are the first video capacitors to be changed ? Do I have to change them all ?

> What are the first tests I need to do for check that the Video/GPU or Sram or CPU chipsets are OK?

> I read that the chip C6270 can be dead. How i can check it and confirm ?

I'll take any advice about White Screen problem, I really want to find a solution  

Thanks to all

[NightWolve]

Ah, definitely you should've changed all/100% capacitors when you started changing any - they are ALL leaking/failed/out-of-spec by now! You always want 100% new capacitors for NEC hardware to rule out any other problems! Before you continue, finish that job first.

[Lunacy]

Thanks !
  Ok I will change all Caps first and i will make feed back.

[Lunacy]

Hi

Full recap was done. Always white screen 

I dont know what i can check now.
No burning points on the mainboard.

What could I consider to be the cause of the problem? It is Hucard port issue or Gpu/cpu issue ?

It seems that the white screen can come from many sources.... i dont know where to start 

If people have some tips ! thanks to share it

have a nice day

[NightWolve]

Ah, too bad!

My advice:
1) Ask/PM @Keith Courage while he's around. He was just here by request.
2) Use the forum Search function for "white screen" - I'm sure I've seen old posts/threads about this problem in my years viewing this forum. There may be some lost clues somewhere in old posts.

Example: Here's a case that @thesteve (a pro EE & Turbo Expert) fixed with explanations of what was investigated/probed/etc. (he's retired though, you can't hire him).

EDIT: 3) To help out somewhat further, I reached thesteve on Facebook and asked for general advice on no boot/white screen states, he said to check the reset pin and address lines!

Best of luck.