Acer Aspire 5100 (HCW51 LA-3121P motherboard)

[ktulu]

Hi.
Got an Acer Aspire 5100 laptop with Compal HCW51 LA-3121P motherboard.
It stoped during operation.

The 1.2V-psu died. (+1.2VP_HT)
PQ27 FET got shorted, therefore the B+ rail protection kicked in.
Removing PJP10 jumper, I measure 7.3 Ohm to GND on the 1.2V_HT rail, is this
acceptable? Would Give around 165mA.
C75 and C24 are good.

Someone who still has this motherboard, please help me by measuring the resistance on C24. (like I said, I got 7.3 Ohm)

Schematic: http://www.s-manuals.com/pdf/motherboard/compal/compal_la-3121p_r1.0_schematics.pdf
Thank You.

[wraper]

Someone who still has this motherboard, please help me by measuring the resistance on C24. (like I said, I got 7.3 Ohm)

Don't know if this is as it should be. But something thereabouts is not extraordinary and most likely is OK.

[ktulu]

OK, the board is back to life again, but I have a new problem.
The only FET i could find is an FDS4410, which has a Qg of 22nC instead of 8,7nC of the original SI4800BDY-T1-E3.

Would this have some bad effects on performance of the PSU IC? Maybe some overheating issues?

Thanks.

[wraper]

The only FET i could find is an FDS4410, which has a Qg of 22nC instead of 8,7nC of the original SI4800BDY-T1-E3.
Would this have some bad effects on performance of the PSU IC?

Most likely not. It will cause issues only if the IC, which is driving it, have an output not strong enough. 22nC is not something huge to cause issues with a vast majority of specialized controller/driver ICs. Check the driver/controller IC datasheet if worried.

[BloodyCactus]

im just about to throw one of these out in  the trash! I believe its a 5100. I'd have to check when I get home from work.

[ktulu]

im just about to throw one of these out in  the trash!

If the board is out of the case, please measure the resistance across C75 or C24. They are on the opposite side of where the CPU is, just near the fan hole. (black tantalums)


ps. I've just noticed, that on the board the FET was actually AO4468, not SI4800BDY-T1-E3 as on the schematic.

[wraper]

im just about to throw one of these out in  the trash!

If the board is out of the case, please measure the resistance across C75 or C24. They are on the opposite side of where the CPU is, just near the fan hole. (black tantalums)

Just don't forget that with and without CPU, this resistance most likely will be different. Also there will be different measurements depending on multimeter as you are passing current through the semiconductors. But as your board works, I assume it is completely OK.

[BloodyCactus]

well, its not out of the case, since its the entire laptop. its a 5004WMLI model.