ALB-Repairs
Member
Hey,
So this is a fun one. I have a 820-3437 clean of liquid damage.
It originally came in with no green light, i gave the SMC a reflow and got the light back. happy days, ultrasonically cleaned, sent out, all working.
It came back a few days later with the same fault., knowing SMC's are not flip chip or real heat sensitive, i think maybe there is some bad pad wetting or something. I remove and reball the SMC. No dice.
I replace the SMC with another pull, Same symptoms.
8.6V is present (first thing i checked)
PP3v42 is present
SMC_Reset_L is present
SMC_BC_ACOK is present
SYS_ONEWIRE is present
I/O connector and cable are clean- the board has been tested with new replacements.
DC board has 3.4V on the centre pin, suggesting that both SMC_BC_ACOK and SYS_ONEWIRE have made it to the DCIN board with no issues.
U7000 has been replaced for good measure.
Ive ran jumper wires to rebuild important traces to ensure there are no cracks in then traces. No symptom change at all.
So here's whats confusing, all the signals are being generated and pulled up just fine, however the SMC isnt communicating with the charger. I have a feeling it has to be a bad ceramic 0201 capacitor in the SMC support circuit but that in itself is a rabbit hole. Anyone got any ideas?
So this is a fun one. I have a 820-3437 clean of liquid damage.
It originally came in with no green light, i gave the SMC a reflow and got the light back. happy days, ultrasonically cleaned, sent out, all working.
It came back a few days later with the same fault., knowing SMC's are not flip chip or real heat sensitive, i think maybe there is some bad pad wetting or something. I remove and reball the SMC. No dice.
I replace the SMC with another pull, Same symptoms.
8.6V is present (first thing i checked)
PP3v42 is present
SMC_Reset_L is present
SMC_BC_ACOK is present
SYS_ONEWIRE is present
I/O connector and cable are clean- the board has been tested with new replacements.
DC board has 3.4V on the centre pin, suggesting that both SMC_BC_ACOK and SYS_ONEWIRE have made it to the DCIN board with no issues.
U7000 has been replaced for good measure.
Ive ran jumper wires to rebuild important traces to ensure there are no cracks in then traces. No symptom change at all.
So here's whats confusing, all the signals are being generated and pulled up just fine, however the SMC isnt communicating with the charger. I have a feeling it has to be a bad ceramic 0201 capacitor in the SMC support circuit but that in itself is a rabbit hole. Anyone got any ideas?