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Customer mentiones importantant data that is not backed up unfortunately. So far the laptop has resorted back to the behaviour of minutes nothing happening and then for a split second a burst of fan noise. This was the same behaviour as before the laptop activation through DFU
Customer came in with an A2179 which stopped working out of the blue. It only had a short burst of fanspin every once in a while. Tried reviving with Apple Configurator, it passed and showed the activation lock on Apple Configurator but not on the failing macbook.
trackpad clicks
now no image...
Gottem! Set the PSU to 1V and max 5A, after turning it on voltage dropped down to 0.4V and one cap lit up: C7702. Only thing now is that I dont have a donor board and also not a new pack of caps with known capacitance etc. What properties of the cap are important? Or is leaving it off a smart...
Changed both CD3215s
chip B gives 20V but currentdoes not come near 1A. Also no apple logo or anything.
chip A is stuck on 5.2V, all LDO lines give a voltage, 1.1/1.7/3.3. Diode mode readings are all equivalent on 0.5V drop with red probe on ground.
Weird thing is, I thought if one port...
Alright! I'll inject voltage tomorrow. Since it's 4.5 ohms I expect it to be more downstream. What max amps should I consider on this line? Voltage preferably not near 3.8V I assume?
I tried injecting a bit earlier when I already thought of it as a short and the resistance jumped down to 0.08...
Yes Diode mode 0.0V drop to ground, resistance mode 4.5ohm. Looked around online and found resistance around this value mentioned, so assumed it was meant to be so low.
Hi,
820-2655-A no power issue, narrowed it down to no PP3V8_AON (at polarized caps like C5890 or behind L5800), checked enable and VIN
PPVIN_P3V8AON = 12.20V
P3V8AON_EN_R = 4.5V
Checked sense circuits resistance between N and P, all between 2.5 and 3.5 Ohms when measuring on C5850/C5830/C5810...
In same order as measurements above:
C3105
C3104
C3108
C3106
C3205
C3204
C3208
C3206
Batterij also disconnected
Ill order 2 CD3215s and before putting the new ones on I will check for shorts on the pads underneath
Thank you for correcting! Is this because of passing through otherwise closed mosfets which are not turned on if the board is not getting the normal power rails?
Values of 0.020 and 0.040 are still unchanged when measuring the correct way with red probe on ground :(.
Yes charger always...
Checked them mutliple times, black probe on nearby screwhole and red probe on the caps around the CD3215s. LDO of both ports hovers around 0.012, LDOD around 0.042/43 for both ports.
Yes sorry, 0.040 voltage drop.
Then again the values of both cd3215 look very similar so since both are probably not bad at the same time is it probable to be a problem upstream?
PPDCIN_G3H not shorted
chip A
LDO_BMC is 0V
LDOD is 1.1V
LDOA is 0V
LDO is 0V
chipB
LDO_BMC is 0V
LDOD is 1.1V
LDOA is 1.8V
LDO is 3.3V
PP3V3_G3H_RTC is 0V, not shorted
Been looking at an A1932 board and I am a bit stuck.
No short on PPBUS_G3H
one usb c port shows 0.14A 5.2V
other 0.15A 5.2V
pulled the ISL off, no shorts found on the pads underneath
placed a new ISL, exact same issue so I guess the old one was fine
PP20V_USBC_XA/B_VBUS reads 5.13V...
Measured again and I think it equates to this:
pin 33: 0.004 (actually not 0.000)
pin 22: 0.004
with board/flex connected
pin 33: 0.004
pin 22: 0.004
This probably means that the easiest way for the current to go to ground is through the motherboard meaning the T2? As the audioboard doesn't...
P5VG3S_EN also missing, could be due to T2 issues DFU or...? Not sure what lead to follow nor can I find any logical next steps when looking at the schematic (googling around for answers right now)
Someone came in with an A2179 which had a liquid spill which wasn't noticed until an hour later. Audio board, fan and battery were liquid damaged but the mainboard seemed fine. Tried to start up using only mainboard and screen which made for a very slow MacBook.
Replaced battery and connected...