Search results

It is the same on both sides.

3 beeps. L7430 = 1.205v

Customer said they "may have spilt" some drink on it. It was still soggy. U.S. clean then oven and now I get a ram beep, so half way there. C7460 gives 0.076 to ground in diode. C2731 gives me 0.539v. I'm struggling to work out how to find the short (which I think is there). Any suggestions?

I'm not picking up on a shorted PPBUS. It measures 0.430 in diode mode but is only about 0.5v PPBus is a flat 0v. Investigating Q7080/5 now. ISL measures okay itself.

So this board came in that is ticking very softly. When I use a knock off charger the green light flashes really quickly. OEM doesn't light up. I tried the mechanics trick and used a small pipe to try work out where the ticking is coming from but it didn't work in this case. Board must be too...

Guess that means it has to be me.

I will check again, but I think it's always at 1.06v

Are bad LP8550s a thing? The last batch (10, used 5) I bought, each one has come back with some sort of problem that looks like a backlight issue. Another just came back with a flickering backlight....

It's not entirely my fault Duke. Those three backlight Airs have me drinking at my desk!!!! No, it has 1.06v both when it beeps and when I bake it a little and it boots.

_L means low == on, high == off. So you'll always have a voltage (3.3v) until the button is pressed which sends it low.

SMC_LID is 3.3 I have performed an PRAM reset. I tried putting 3v on BKL_PWM to get the screen at full brightness, but nothing changed.

Sorry, I mean L7550 R7601 seems to measure correctly at 2.2ohms. Edit: I don't think C7602 is shorted, I think something on the ::2 side is shorted. If I put the probe on ::1 I get a mostly normal reading.

As in subject, board just gives three ram beeps. If I heat up around U7600, the board works fine until it cools down again. When hot, I get power at L5550 & C1724, as soon as it cools though, no power there. C7602::2 measures 0.000 in diode mode.

It is, at 2.84v @ R7715

BKL_PWM with a DMM is 1.46v

Q7706::3 = 2.843v D7701 is stable now. I measured it several times before to make sure it was fluctuating.... These three backlight boards are sending me loopy.

I just noticed that I am getting an unstable reading on D7701 It goes from 8.59 down to about 6v then back up again. Ever now and then it seems to drop to 0v. Any idea what that means?

If I put power on C7901, U7900 just about blows smoke. What is SLG5AP439 though, I can't find the chip anywhere.

I haven't replaced it again, have finally run out of LP8550s. For some reason nearly every job the last ten days has been LP8550 related one way or another.

Off to investigate! Thanks for the lead.