3,3v
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Measure the voltage to ground (not diode mode) directly at S5_PWRGD (Pin #20) on the U7501 IC.
Next, remove all power -> meter now in DIODE mode -> red meter probe to ground; black meter probe onto S5_PWRGD directly on U7501 IC.
Finally, still with no power -> meter in DIODE mode -> short the meter probes and you will hear a tone beep -> one meter probe directly at S5_PWRGD (Pin #20) on U7501 IC and the other meter probe on the pull-up resistor (R8141) on the same line. Do you hear a tone beep?
Confirm again that R8141 has 3v42 on one side of this pull-up resistor. This 3v42 must be stable.
This signal must be HIGH to denote that this power rail is OK unless U7501 is defective / not soldered in properly / U7501 replace is not the same as the original (confirm the topside markings - are the latest replacements for U7501 new or from a donor board?)Comment
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I have Tried all those things before: pwrgoodline is not shorted, 3v42 is stable, each pin of u7501 is ok and goes to the right Point… so even pin 20 beeps to r8141
at this point, i will try to solder another u7501Comment
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tried another u7501, still the sameComment
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This same power good signal enters the SMC. It is possible that the SMC is defective and causing this line to become stuck at a logic low. The only way to rule out the SMC is to locate a sweet location on this trace to cut to isolate the side that goes into the SMC. Respectively, this trace will need to be repaired after this review. You mentioned that the power good line is not shorted but no measured values. Assuming the line is not shorted, then it must be the SMC who is tanking this line.Comment
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i will go crazy...i've soldered another smc..now i have 3,2 on the other side of r8141 but no power led on magsafe... i have even pwrbtn_l 3,4V!!!!!
ppbus_g3h is 8,16, PP3V3_S5_SMC_VDDA 3,4 sysonewire 3v (should be 3,4?!) PP1V2_S5_SMC_VDD 0,9 v!?!?!?!? should be 1,2? (line is not shorted)
Last edited by phantomEVO; 03-07-2024, 03:00 PM.Comment
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Yes, PP1V2_S5_SMC_VDDC should be 1v2.
Remove all power -> meter in DIODE mode -> check the diode mode readings for this rail. What is the measurement?Comment
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0,510Comment
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Good reading.
Follow the guidelines here (same case with the PP1V2_S5_SMC_VDDC):
820-00165 PPBUS_G3H : 0V | Rossmanngroup ForumsComment
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SMC_RESET_L : 3.4V
SMC_WAKE_L : 3 V
SMC_CLK32K : 0V
SMC_EXTAL : 0V
SMC_XTAL : 0.4V
PP3V3_S5_SMC_VDDA : 3.4 V
PP1V2_S5_SMC_VDDC : 0,9V
PP3V3_S5_AVREF_SMC : 3.28V
GND_SMC_AVSS : 0V
SMC_TCK : 3.4V
SMC_TMS : 3.4V
SMC_TDO : 3.4V
SMC_TDI : 3.4V
i'm thinking that this smc is not good (i've bought for new)Comment
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Flux it well and try a reflow but otherwise, yes, could be a defective SMC. They should not be new but pulled from a donor board. This is a power rail created by the SMC itself to operate internal logic. Juts be gentle as to not tear any of the BGA balls / pads. Tearing balls is bound to inflct some level of pain.Comment
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i will do a lot of soldering on mobile phone....even cpu! so is not a problem to solder an smc..i will solder again the old smc...
unbelievible that i have s5 pwrgood with this smc -.-'Comment
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Aha moment!!! As noted that the SMC can pull down this line. Now it is confirmed.Comment
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Problem is to find a donor board?
Could I take from 820-2796 ??Comment
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SOLVED!!! I've resoldered the originaL SMC!!!!!Comment
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Hi,
my MacBook Pro 15" 2018 Touch Bar (A1990) doesn't charge anymore. Board# 820-01041-A
I'm not experienced in diagnostics, but I want to try to solve the problem with your help, because every local shop charges around 600€ (650 usd). Which is the value of the whole Macbook.
The Macbook was charging when suddenly the "charging sound" appeared every other second for around 4-5 times.
After that the Macbook was dead. It isn't charging anymore.
The USB-C Port where the charger was plugged is burned. Also The Cable and the... -
Hi all , thanks for having me & I think this has been asked before but my case seems a bit odd.
I have a MacBook Pro , board 820-2915a and it turns on , chimes etc etc , keyboard lights up, fans spins , can turn caps lock on/off but screen is dead.
Iv tried the resets , shine torch through back logo , nothing , it seems the screen has no power. If I plug charger , it charges but if I disconnect battery it displays green light but won't turn on. Iv tried screen on with another board & it works & seems I'm not getting any voltage at pin 2 , next to ground pin .
is this... -
Hello...
My sister purchased an M2 MacBook Air a year and a half ago. While she was using it a week ago, it randomly shut off and no longer powers on. There are no signs of life and not even the MagSafe indicator LED lights up.
We took it to Apple and they disconnected the battery and tried a bunch of stuff before they declared the logic board "brain dead" and quoted us about £567 to replace it. Typical of them...
eBay replacements run about £367 with the Touch ID sensor included.
I did consider to probe the logic board for shorts... -
Hi everyone!
I have a 2018 MacBook Pro (with Sequoia OS) that I've been using for years with no problem. I recently received an M2 MacBook Pro so I'm mostly using it and not the 2018 one, but since a friend of mine needs a computer, I thought I could restore my 2018 and give it brand-new-like to my friend.
I tried using the built-in tool to restore the MacBook (Settings > General > Transfer or restore > Delete) but it got stuck when trying to remove the Find Device configuration (it asked me for the password for my old Apple ID -now I use the same account but...06-27-2025, 08:54 AM -
HELLO FELLOW COLLECTORS, How are you doing, I hope GOD always gives us good health, I'm here asking for help to work on this MacBook Air, to be honest, this is the first time I'm dealing with a MacBook machine, and I immediately decided that the ISL 6259 IC and after I replaced it it still didn't work and I found that the CHGR_CSO_N & CHGR_CSO_P pins had a short circuit.
can anyone help me guys?
Comment