Toshiba L300 no POST - schematics + multimeter readings inc.


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Hey all. Getting no replies on a few other forums and I see we have a few board-level repairmen on here. So worth a try eh :)

Schematics are here: Satellite L300D_-_INVENTEC_PS10A_-_6050A2174501_-_REV_X01Sec.pdf

I have an L300. Powers, no POST. Isn't the NEC/Tokin cap problem because this version of the board doesn't have one.

All voltages are present that I can see - checked every single test pad on it, V5S, V5A, V3S, V3A, V2.5S etc etc are all working. CPU, SB, NB and Winbond chip all warm up like they should.

Very strong sulfurous smell, a bit like BO, is coming from the board around the 3.3v regs that are linked to the Winbond chip. It's absolutely horrid around this area:


C191 (different area of the board) is slightly blackened but appears to be charging/discharging okay and volts going through it are all fine.

C161 doesn't seem to be discharging in one direction - but it's in parallel with some resistors so maybe it's a false positive?

Some odd readings around the BIOS chip but I have yet to confirm.