Re: 2011 MacBook Pro 13 green light, but not working

Ok, I will order a donor board, although I feel a little uneasy as a noob at this to get something known to not be working, it might always have the same issue... I do have access to an oscilloscope too with more than enough bandwidth, the issue is I'm not sure what a good output would look like, particularly as there might be something else tampering with it, so what you say makes perfect sense.

Nothing seems to be physically broken and I have measured a bunch of components around the U7200, but I need a better DMM...

Re: 2011 MacBook Pro 13 green light, but not working

Just asserting what I know so far:

PP3V3_S5 is 0v, even though all the signals and voltages going to U7200 are correct;
SMC_PM_G2_EN (3.46) -> U7941 ~> P3V3S5_EN_L (0v) -> U7200 which, with P5V3V3_REG_EN (3.42) to enable the U7200 and P3V3S5_EN (0v) to disable the Q7221 mosfet so ENTRIP2 is not shorted to ground should turn the step down converter driving the PP3V3_S5 output. However that output stays at 0v.

The other output, PP5V_S3, is not turning on also, but that one is actively disabled...

Re: 2011 MacBook Pro 13 green light, but not working

P3V3S5_EN is 0v at Q7221 pin 5 and TP below.

Resistance from PP3V3_S5 at L7220 pin 2 or adjacent TP to ground is 1.017K (DM on resistance, positive lead to ground, the other way around R fluctuates a lot, I assume due to some polarised cap along the way?)

Re: 2011 MacBook Pro 13 green light, but not working

I'm at a loss again... P5VS3_EN_L is high because Q7911 is not conducting to ground, if I got this right. So I got:

R7913 - 3.47
Q7911 gate 1 - 0v
R7914 - PM_SLP_S4_L - 0v

and PM_SLP_S4_L should be high, which I take to mean it goes low on SLEEP, maybe?

I don't find a short to ground PM_SLP_S4_L, so there's that, but otherwise I have no idea what to do.

Re: 2011 MacBook Pro 13 green light, but not working

I have checked the wattage of the PSU on the 15" and it correctly reports 85W.

I took some measurements as per the sequence described, and it all points towards the U7200 or thereabouts, though I might be biased due to the number of times that is the culprit. I have measured the following power points:

PPBUS_G3H - 12.57
PPDCIN_G3H - 16.85
PP3V42_G3H - 3.47
PPVRTC_G3H - 3.47

PPBUS_S5_HS_COMPUTING_ISNS - 12.57
PPBUS_S5_HS_OTHER_ISNS - 12.57
PP5V_S5 - 4.96...

Re: 2011 MacBook Pro 13 green light, but not working

This is embarrassing, I can't even read my own notes...

So, yes, all the measurements were taken with nothing else connected, only the 85w magsafe (from a 15", it's the only one I have still working) and P7 to P9 have 12.57, same as PPBUS_S5_HS_OTHER_ISNS.

The latter was a confusion from checking P5VS3_EN_L on the mosfet, which has 3.4v but seems to, from what I understand, come from an inverted gate on the U7941, so should be 0v? On the other mosfet from the same chip, the P3V3S5_EN_L reads 0v....

Hello,

I have a 2011 MacBook Pro 13" as described in the title, specifically an A1278 with the 820-2936B logic board.

It was sitting for a few years, I booted it up to make a backup and install fresh during which I noticed the 100% fans and 90C temps on the CPU so, as I usually do, I opened it to refresh the thermal paste on the CPU and give it a good clean on the exhaust side.

It wasn't easy to get the board out, and it actually ripped a bit of the black insulation that is covering the backside of the keyboard, around where the CPU is. That's fine,...

Re: New Members - please post your introductions here

Hello all,

It's been a really long time since I posted on a forum, what a refreshing change of pace

I'm an ageing coder that always tinkered with electronics, and I've always enjoyed how communities help each other in these technical fields, and I do need some help now, so there's that. I'll be sure to pay it forward though, as I have always done to be honest...

So, greetings, it's a pleasure to be here.