820-3115 Quarter Fan

brunomotter

Member
Tried. Same thing. I noticed high consumption of current on L7510 and L7520(around 4.5 amps) when injecting 1V on those coils. If I remove Q7520 and Q7510 it draws only 0.75 amps on bench PSU. Tried replacing both mosfets, still same abnormal consumption. I think there may be a short to GND before mosfets.
 

brunomotter

Member
L7510:

Black Probe on GND: 0.2Ohms
Red Probe on GND: 0.3 Ohms

L7520:

Black Probe on GND: 0.3Ohms
Red Probe on GND: 0.3 Ohms
 

brunomotter

Member
I replaced U7400 and Q7510 and short gone, no more abnormal current consumption but no power! Just green light, no more S0 state. Resistance to GND raised to 1.4 Ohms on both coils.
 

brunomotter

Member
Reading a bit lower than other similar board I have here. Now it's reading 2 Ohms and 2.3 ohms respectively, against around 3 Ohms from other board. I think CPU may be OK.
 
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