A1286 820-2915-B CPU throttling

[cruiser_]

Re: A1286 820-2915-B CPU throttling

Q7050 is pmosfet 'in front' of battery

[mon2]

Re: A1286 820-2915-B CPU throttling

Yes, agreed. What is Q7050? Do you mean R7050?

See here - looks like the same fault:

https://boards.rossmanngroup.com/thr...ly-slow.24296/

[cruiser_]

Re: A1286 820-2915-B CPU throttling

Found shorted q7050. Fixed charging issue (above 0.5A) but hasn't changed a thing otherwise ;(

If smbus was shot, wouldn't aht/ASD catch that?

[mon2]

Re: A1286 820-2915-B CPU throttling

Review the voltage to ground of the SMBUS lines. The sensors are read from the same interface. Check each SCL and SDA line on the board. Each is a suspect.

A good pair to check is the one on the battery connector. The ESD tvs diode blows and causes the smbus lines to halt communication. For this case, the damaged TVS diodes need to be removed off the board and then test again. From memory, d6950(?).

[cruiser_]

Re: A1286 820-2915-B CPU throttling

hi mon2! I tested with two genuine 85W adapters, both recognized ok (wattage, versions etc) in the power report. SMC_BC_ACOK is high.

Trying to figure out the charging circuit a bit more, assuming the battery is ok (two wrong ones in a row a possibility but unlikely...) - low charging puzzles me. Could this be related?

One extra thing I noticed, which is bizzarre. Running in SMC bypass mode never fully boots up - restarts about 3/4 way done.

[mon2]

Re: A1286 820-2915-B CPU throttling

Test again with a higher power adapter. The logic board will throttle the CPU if the power adapter is underrated.

[cruiser_]

Late 2011 macbook pro, runs 'fine' off the AC adapter and off the battery.
However, CPU is throttled to 0.8ghz all the time.

Ran AHT, ASD (both EFI & OS) - all passed with flying colors.
Isense & Vsense readings are OK, do not seem to fluctuate more than expected.

Battery info is read correctly and it is charging fine (albeit quite slowly, 0.3-0.5A). Replaced battery - no difference.

A bit lost now, any help would be appreciated.