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Yeh, I did. Check it every now and then in case I blow it while working as I have done once before.

Measure PWM with an oscilloscope? My DMM is telling me it's 1.46v which I guess is an average of the pulses.

Ha! You're actually right. How can the Boardview say one thing and the diagram say another.... Either way, the short on PP3v3_S5 went way when I replaced that cap.

Yes, showing you the power rail on the right hand side.

I already replaced LP8550. Is there a way to measure it?

Look at what diagram? It clearly says PP3v3_S5....

Definitely an image.

The rMBP have the other side of the LVDS (or DP really I think) under the plastic cover. It's not under the glass like with the older A1286 et al.

Originally had liquid damage. Swapped the LED Driver. Worked okay. Now the backlight is either full brightness, or anything else and it's off. Guessing some sort of PWM issue?

Yes, I checked the trace when I replaced the LED Driver. BKL_EN and PWM are missing, one both boards. I have three of them that have come back now with all similar problems. Could it be a bad batch of LED Drivers? I'm guessing pin 1 of R7704 shouldn't measure 0.000 in diode mode?

No Title It's definitely 3v3_S5 on my screen.

C9480 was glowing when I put about 3amps through it at about 0.9 volts.

When doing a final test to return to customer I noticed that the backlight is out again. In fact I have two of them now. BKLT on LVDS is measuring 8.59v. Is this the LED Driver or feed back? Both of these had the LED Driver replaced.

Thought I would ask incase someone has some experience. I have a customer that wants me to get some data off one. Using an ACR38 reader but don't actually know what the card is (it has no markings). Only responses ever returned are 'Transaction failed' and 'Protocol mismatch' Writing it in C...

Took y our advice and bought a 10A supply. Found the short in under a minute. So now I get a green LED and nothing else. Shorting SMC_ONOFF_L does not get the fan to spin. Not being familiar with iMacs I don't know if I can turn it on with no screen, button etc attached; so should it be...

Liquid damaged. bklt bins burnt off on the LVDS connector, replaced it, twice. LED Driver had a burnt out pin 8, replaced it too. Still no backlight. I'm getting ~8.5v on 3 & 4 of J8300.

Don't you always need to evolve though? Repair won't "end" but it will definitely change. It will be come more specialised meaning the ones keeping up have less competitors. I've been a programmer for over 15 years now, and have always had to evolve my methods and practices. Even changing...

S5_pwrgd is stable. Ugh, G2_EN is cycling. But every five or ten powers I can get it stable, then it boots fine.

PPBus is stable. It seems to be boot every now and then, but mostly power cycles. Will check G2_EN and S5_pwrgd in a moment.

Just noticed that PP3v3_S5 is power cycling. Didn't pick up on it the first time I looked.