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Well I thought i'd have a go and reflow SMC anyhow - board now powers up in normal mode but not with battery connected. Looks like i've got a dead battery as well.

Update - in SMC bypass mode it starts and runs. So we looking at bad SMC? Presume i'll need to get a donor SMC off another 820-00281 or are the ones from the 12" Macbook compatible?

Yes seeing pulses on L7211, L7221 and L7231 - i'll try smc bypass mode and see if it powers up

PM_SLP_S3_L is also pulsing - all other rails (at big coils) appear to be pulsing. One strange behaviour appears that PM_SLP_S0_L pulses to 3.3v then drops down to 2.75v and stays there after everything else has pulsed

after repeat checking yes P5VS4_PGOOD is pulsing up to 3.3v and at L7600 it's pulsing up to 5v.

Diode reading at L7600: Pin 1 - 0.418 Pin 2 - 0.417 A scope is something I am thinking of investing in but currently do not own!

Yes pulsing PM_SLP_S5_L - cannot seem to see any pulsing of PM_SLP_S4_L P5VS4_PGOOD is not present although R7801 seems good. Should add - no pulsing at all with SMC_ON_OFF_L only when i replug charger then i get the quick pulse then off to S5 state again. Should add as well that after more...

Seeing a quick pulse on the PP5V5_S4 and PP3V3_S4 power rails to 5v and 3.3v. ALL_SYS_PWRGD - missing, the S0 rails don't pulse - only seem to have S5 rails after the pulse. Should also add I checked PM_SLP_S4_L which is low 0v.

So my second 820-00281 in as many weeks. Customer advises they were watching youtube when it just shut down no power. Have taken it in and board looks very clean but is exhibiting the following behaviour: With battery plugged in i'm not getting PPBUS generated and my charger isn't able to power...

ultimately I gave this one back to the customer as it was in a state where working reliably on the external display only - i was missing both backlight and image on the lcd initially then after plugging external was just missing backlight.

actually no the touchbar and touchpad/keyboard are working fine when it's in this mode

So i'm back to the same stage again today - was working perfectly yesterday and now it's behaving as it was before - booting only to external display like the lid is closed. I would presume at this point we're looking at a problem with the SMC itself as it's the only thing I can think of which...

So I tried to pull one sensor out and got the same behavior again - in fact it seemed fully stuck in lid closed mode. So i've pulled off U5255 and wired SMC_LID directly to PP3V42_G3H now testing it and so far so good. Probably U5255 has gone faulty

Think i might have nailed down the problem - I decided to use a magnet to individually trigger the SMC_LID sensors - when I went near two of them (the touchpad and left side one) it behaved normally. After I went close to the right side one the problem occurred again. Can it be removed with no...

Don't suppose you have a link to a known good full BIOS for this board? I can't seem to find the right one! This board is really strange - if I get it working and don't open/close the lid it's working 100% perfectly responding to power keys no problem, the second I open/close the lid it goes...

no the board ignores on off request regardless whether in the case or not - it'll consistently turn on when charger is connected but ignores the power button whether inside the case or outside. With the screen attached it doesn't even turn on consistently with the charger however - all testing...

It appears to react with usb mouse when it's on it's own without anything else connected. Just as an update with more testing I did - after taking customers data off i've left it in a normal open position but off for the whole weekend turned back on and then off no problems shutting down or...

Received an A1707 2016 touchbar 15" in yesterday (820-00281 / 661-06279) with a stange fault. Customer states they dropped the Mac and afterwards it wouldn't power up - can confirm there is a big dent on the corner of the housing. I've opened it up pulled the battery and then reconnected - when...

Based upon the assumption you are trying a known good battery: 1) Check PPBUS Voltage is normal 2) check inside the battery connector on the board for any corroded pins - i've seen liquid move down the cable from the battery before and corrode the connector inside. 3) Check R5380, R5381 and R6950

Finally got back to this one after a busy week; there were a catalogue of problems: 1) Under U1950 pad 8 was corroded 2) Pad 1 under R8156 was corroded 3) the SMC hadn't soldered on correctly when I reballed it earlier After fixing all three issues it's now starting normally.