Sony Vaio VGN-S4HP (PCG-6G1M) cold start problems

[tozitom]

Hi members, hope to get some help on my 1º post on this mobo; I could not find the schematic so far, another problem is the board doesn't have components designators on it!!!
So here's the resume of what's happening and what I've done so far:
- on power ON: we can hear HD starting but all shuts down after 1 second.
- tested usual perif, but all OK (mems, CPU, HD, TFT, ...)
- Measurements show presence of usual +5V, +3v, +1,5V on some step-down ICs, with laptop OFF (see picture)
- when trying to power ON, I can measure +1,8V for about 1s, but as said mobo shuts down
- continuity measurements on +1,8V output shows no shortcut
- measurement under NVIDIA video driver shows shortcut on lot of caps - here we have another step-down IC same as the ones in picture.
- after tested most of those caps (big and small, tantalum+ceramic) shortcut remains...

So here the strange thing: after those operations, and while mobo was still warm (after soldering caps under NVIDIA), laptop worked fine from several hours (with several power ON/OFF); so I thought I had a temperature problem and tried to cool down some areas to diagnose but no success...
I tried some more caps (shorted area) but still no success.
Now, even with warm mobo laptop doesn't start, only same as cold = trys to start but shuts down immediately.

Does anyone have any experience with this mobo, or schematic would be great also!

Thanks to all.

[caspian]

Re: Sony Vaio VGN-S4HP (PCG-6G1M) cold start problems

First, read the mainboard model that starts with MBX... somewhere on the mainboard. Then, find its schematics and upload it here.

[tozitom]

Re: Sony Vaio VGN-S4HP (MBX-129) cold start problems

First, read the mainboard model that starts with MBX... somewhere on the mainboard. Then, find its schematics and upload it here.

Thanks for your reply. This board is a MBX-129. I've been searching for schematic but only found MBX-126 so far... anyone has this schem?