820-00928 20v 40ma


Hello, I have an 820-00928 with 20v and only 0.04a which jumps to 0.40a and back again every 15 seconds.

No obvious signs of liquid and wont start on SMC bypass

Testing board on the side only with only a dc in board connected, I get:

PPBUS_G3H = 12.52
PP3V3_S0 = pulsing
ALL_SYS_PWRGD = pulsing
PP3V3_S5 = 3.29 solid
PP3V3_SUS 3.29 solid
L7211/21/31 all 0v

Do you think the CPU is dead? Maybe try a new BIOS?


Staff member
Check for pulse at L7330/7960/8000.
Also check at LA300/50 and LA640/50.
Don't forget SSD power rails too.

Looks like board tries to start and gets blocked because of short.
So compare resistance to ground at CPU and GPU coils with good board.


Hi 2informaticos, thank you for your help.

L7330 and L7960 are pulsing but the multimeter isn't quick enough to catch the peak (possibly 0.8v-1v).
L8000 has nothing on pin 1 P1VS4_PHASE but does have 1v constant on pin 2 PP1V_PCH_REG_R

P12V_SSD_VPP_SW & _L are holding at 0.15v and pulsing maybe 1v
P1V0_SSD_CORE & _SW are pulsing somewhere around 1v
PP3V3_SSD_ISNS_R is pulsing 3v
PP12V_SSD_VPP is jumping from 5v to 12v
PP1V8_SSD_FMC is pulsing 1.5v

I don't have a known good board for this in the building, just scrap half boards for parts.

These are the resistance values though.

L7410 = 3.7ohm
L7420 = 3.7ohm
L7211 = 2ohm
L7221 = 2ohm
L7231 = 2ohm
L7330 = 11.4ohm
LA640 = 2.9ohm
LA650 = 2.9ohm
LA350 = 34.5ohm
LA300 = 117ohm


With the battery plugged its pulling 20v 3.6a but I suppose thats just battery charging only as everything just stays pulsing