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I have an 820-2936 with Intermittant Fan Spin (no Liquid Damage)
PP3V42 - 3.47V
PPBUS_G3H -12.58 V
PP5V_S5 - 5.0 V
PP3V3_S5 - 3.3V
PP5V_S3 - 5V then off, 5V then off
PP3V3_S3 - 3.3V then off, 3.3V then off
I tried new clock chip, same result. Any ideas?
I have been hearing of more and more issues with Macbook Pro 13 2012/13 and random trackpad movements, tried cleaning and PRAM reset, no luck.
Has anyone heard of this being HW level issue?
No liquid damage to my knowledge.
Sense circuits look good bottom R7051 R7052 is 3.4Ohm, from R7021 to R7022 is 21 ohm.
I was measuring around PPBUS MOSFETS and magically PPBUS_G3H went to 12.68, so I hit all the points I was measuring with solder and Re&Re the ISL6259
All is good now ASD passed
Liquid Damaged 820-2936 no green light, no fan spin. I cleaned up corrosion around ISL6259 , LCDS connector, U5400 and Q5300, Q4262 was corroded and replaced from donor board, a few misc caps and resistors replaced due to corrosion (mostly around U5400 and Q5300).
Plugged back in and got Green...
I checked external, same deal, same flicker.
The machine came from another shop, I don't think this original logic board for case as no liquid evidence on logic board, normal grime and dust so it hasn't been cleaned either.
I suppose a careful reflow of MCP couldn't hurt at this point.
I had a look at PP1V05_S5 on scope, it measures 1.06 and it looks like there is about 10mV of 300KHz ripple on it. I also checked PP3V3, it has no detectable ripple. Not sure if thats normal or not.
Not sure if anything else I can check, or just call it bad GPU and turn it into a donor. Any...
I have 220-2936, bongs, boots, charges, green light etc, all good.
The video flickers a couple time on initial boot and when in full screen video, since its Intel HD (not ATI or NVidia) I'd like to think it may be power instability rather than GPU issue.
I replaced C167D and C167E on PP1V05_S0...