Toshiba Satellite L655 won't start.. easily

[VidindkiG]

Hi everybody,
I have on my desk my friend's laptop and it drives me crazy because it wont start... easily.
mainboard: 6050A2332301-MB-A02
cpu: Intel i3-350M
gpu: Ati Radeon HD5145

The Line LED is ON. Pressing power button makes a few LEDes flash ON for a very short moment: PowerOn LED; HDD LED (not every time) & WiFi LED. Then all goes OFF for a second including Line LED. Also the fan turns ON (not every time, along with the HDD LED). Then the Line LED goes back ON. If you are patient enough after around 100s of trials, 10 - 15 minutes later laptop will starts eventually. And it will work like a charm. Ones having OS loaded it will successfully take CPU-Z's Bench & Stress CPU or FurMark tests like a hell.
This behavior is observed exactly the same no matter if changing power source, having battery in or out (just to mention that the battery is dead long ago) or changing with other memory modules.

Any help will be appreciated.

[piernov]

Re: Toshiba Satellite L655 won't start.. easily

Try to flash the BIOS

[VidindkiG]

Re: Toshiba Satellite L655 won't start.. easily

Turns out the problem was caused by this little bastard - Q6002 - N-Channel 30-V, 13A (D-S) MOSFET. Not only there was cold joints on all Drain legs (5, 6, 7, 8), but those legs was pretty rusty as well (see attachments). Some chemical & mechanical cleaning along with soldering rework does the trick for now. When everything started behaving stable I updated the BIOS for second time as well (v2.40 - if someone has newer version will be very welcome to share with me). For just in case.

Next, a clean installation of OS was performed. Couple of hours of testing later all was good. It was time for reassemble the whole laptop. Finally I plugged back the battery (still knowing it was dead). Immediately when I powered the laptop on it started to sing. Very hi pitch noise was coming from one of the DC-DC converters on the board. Five minutes later I decided to remove the battery. But the damage was done already. I noticed that the connector of the battery and the zone of the laptop near the connector side was quite hot.

Tremendously worried I decided to turn it back on.
OS loaded like a charm, machine behaved stable but then I noticed another issue - the fan was spinning at full speed all the time. At some point the CPU core temp was around 40° with the fan blowing COLD air.

A few restarts later, uninstalled all those updates that manage to sneak in, recovered from restore point - none of them helped - I realized it is time to inspect again the main board. What I found out was that little bastard (Q6002) was almost unsolder its Drain legs, which was so badly oxidized that I though that will be impossible to repair.

Well, half an hour later, again chemical & gentle mechanical cleaning, soldering rework, the bastard was back and ready to take all that heavy amperage back again. And I realized it is a good time to order a new chip for replacement as well.

Then everything was like before - smooth, quiet and stable behavior, not getting too hot and of course WITHOUT the battery! At least till I get Q6002 & the battery replaced with new ones.

That's it for now. I hope this story could be helpful to someone.

I would like to say Thank you to Duranotron and piernov for their contribution providing me with the board schematics (here)!

Cheers!