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never mind.. I should have done a DFU restore after replacing the ALS CAM coil and U5200 chip because now [B]it's all good[/B]..never mind.. I should have done a DFU restore after replacing the ALS CAM coil and U5200 chip because now [B]it's all good[/B]..never mind.. I should have done a DFU restore after replacing the ALS CAM coil and U5200 chip because now [B]it's all good[/B]..
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It did not give any image.. when I mentioned that it booted normally it happened when? Here is what happened:
I left it two days ago to do DFU restore and left the office.. next day I came it was on question mark meaning it completed and it was DONE... all OK.. computer was perfect up until I took the board of to clean.. when I returned it to housing; not image.
I did the same thing yesterday leaving it to do DFU restore and left the office.. same thing happened and now it boots and shows image without issues.. no problem whatsoever.. I'm sure if I take the board out...
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no external image..
I mentioned that it boots normally because it showed an image and booted normally one time without issues and then it stopped...Last edited by iMuhtaseb; 01-04-2025, 10:40 AM.
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A1932 no image
I've stupidly connected A1932 screen while the battery is plugged in..
ALS CAM coil was burnt to ashes.. replaced it and diode mode readings all ok
U5200 (I2C TCON) chip had little high diode mode readings on the display lcd not T2 side; replaced and it diode mode are better..
but still no image
I've taken diode measurements from LVDS connector; all ok now (edited)
what am I missing?
no 5v sw no 3v sw
it booted normally and DFU restore successful...
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WLBT_PWR_EN is a 1.8v line.. can I pull volt from 1.8 s2 to the power enable line?
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A2681 820-02536 no Wi-Fi
the board came with no power symptoms and found a blown cap (if I remember correctly it was PP3V3_S2_LDO line)
after cap replacement Wi-Fi is not turning on.. after few reads found "WLBT_PWR_EN" high in diode mode and not present when board is on.. thought PMU is faulty, replaced it but sadly Wi-Fi is not on as it is.. meaning this is a bad Wi-Fi chip.. and since Wi-Fi chip is paired to the M2 SoC changing the chip is meaningless..
all wifi chip vcc lines are on = 3v3 aon wlbt, 1.8v s2 and 1.25v s2
Is there other workaround for this issue?Last edited by iMuhtaseb; 12-16-2024, 09:51 AM.
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RIP
PP3v3_S5 short to ground..
After volt injection PCH is warm.....
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I went on each inductor all around the board.. no shorts found..
I will look into that article tomorrow cause I'm leaving in a bit, although it does not quite match my board's symptoms but nevertheless, worth the shot....
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Using Apple Original 96W power adapter ofc.
Power draw:
After it switches to 20v
Amp consumption goes into a pattern:
[B]0.11[/B] > [B]0.22[/B] > [B]0.14[/B] > [B]0.23[/B] > [B]0.43[/B] [SIZE=10px](just for a sec)[/SIZE] then drops > [B]0.11[/B] > then to [B]0.06[/B] and stays thereUsing Apple Original 96W power adapter ofc.
Power draw:
After it switches to 20v
Amp consumption goes into a pattern:
[B]0.11[/B] > [B]0.22[/B] > [B]0.14[/B] > [B]0.23[/B] > [B]0.43[/B] [SIZE=10px](just for a sec)[/SIZE]
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PPBUS_G3H [B]12.61v[/B] nice and stablePPBUS_G3H [B]12.61v[/B] nice and stablePPBUS_G3H [B]12.61v[/B] nice and stable
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I put the board under the thermal cam again, found U8510 heating.. tested the pads and found SMCRST_TIEOFF almost direct short to ground instead of 0.721 in diode mode..
No caps lock toggle.. nothing on external monitor.. put the board again under the thermal cam.. PMU, T2, TPS are all getting warm which is normal.. I found wifi chip around 31c.. idk if it has anything to do with the issue..
PMU bucks are present.. 5v G3s present.. 1.8v G3S present.. SSD rails available and stable.. no volt in CPU coils
Hate this machine hate this model hate all T2sssss...
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A2289 (820-01987) 3v3_G3H_RTC
As always with nearly every T2 board, board is squeaky clean.. 3v3_G3H_RTC had a short..
Of course in TPS chip.. I replaced it..
Found another short in 3v3_G3H_RTC in SoC PMU; replaced..
Board was taking 5v 0.40a on one port and another port is erratic.. ammeter turns on and off.. In thermal camera found TBT ROM was getting warm up to 38c.. [B]PP3V3_UPC_XB_LDO [/B]had low diode mode reading..
Replaced TBT ROM from another known-good A2289..
Now board switches to 20v and consumes low wattage.. gets into DFU revives and restores successfully without...
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Ok here is a quick breakdown what I concluded:
I put the board in the housing to check for vcore voltage and it didn't drop to 0.6v it dropped from 1v to 0.92v.. I kept the board on inside its housing and it actually gave Apple logo after 10 minutes and stayed there..
I shut down the computer and put an obstacle on the alt "option" key to keep it pressed to see if it goes to boot select menu and it actually did.. I plugged in my USB drive and it freeze for a bit then recognized it and started booting.. this process alone took like 30 minutes..
After...
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I will check that tomorrow, although this board should present an external image at least even bare board as far as I remember..
In the meantime I tested the board with a external USB.. sadly no activity on LED indicator.. on other boards there's blink but on bad board no....
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hmmm..
L7210 turns on after PD switches to 20v @ 1v for exactly 10 seconds then drops to 0.92v for a second then drops to 0.65v and stays there..
L7220 same thing; 1v -> 0.92v -> 0.65v
That's a remarkable observation [USER="295753"]mon2[/USER]!
Bu what does it mean? 😁mon2
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Sorry about the post, it's been cluttered for my numerous and attempts and recording each step here..
USB-C ports switch to 20v and current draw goes to up 0.8 mA then drops to 0.4 mA and stays there..
Symptoms: CPU heats up.. S0 is present but no enable signals coming to power on the LCD..
[B]PPBUS[/B] is stable @ 13v Diode mode 0.454
Resistance mode 55 kOhms
[B]PM_SLP_S4[/B] and [B]PM_SLP_S3[/B] are present
SMBUS SCL SDA lines from 0 to 5 tested with diode mode measurement and compared to another...
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I've put another known-good board of mine to the customers housing; my board showed an image for brief moment and it stopped.. now it is exhibiting the same issue.. I lost a good board 😢
What I connected to board are Touch Bar Display, Touch Bar Touch, Trackpad, Keyboard, Audio Jack, Touch ID, Type-C connectors and display...
Diode mode are ok in LVDS, TB disp, TB touch, trackpad, keyboard, audio jack, Touch ID.. I am yet to test type-c connectors.....
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I found a small crack on U4200; replaced it same thing
I replaced both hall sensors in hopes; sadly didn't fix
I cannot find any enable signal for the screen..
I don't know what's wrong with this haunted computer; could it be firmware?...
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I checked the coils around U4200; ok
I checked the LVDS connector in diode; readings OK compared to OBD and another board
Seen a vid on YouTube where a guy replaces the audio codec jack and it fixes the issue; I didn't find any abnormalities, shorts or high/low diode readings.....
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I have taken a look at U3610, yes, nothing seems off.. I'm thinking of reflowing tbh.
SMC_LID is a great hint! But sadly it is present at 3.4v Hall sensors are on 3.4v...
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