Okay, I get 12.3v on the Enable pin of UC300
The resistance to ground on pp5v_s2 is 1 mega-ohm and lowering
TimScrawn
Member
Last Activity: 03-07-2026, 05:13 AM
Joined: 12-31-2021
Location: London
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I will check for you now, thanks bud...Leave a comment:
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Hi Mon,
Thought I would just come back and give you an update. So one of the PD controllers I have since replaced from a donor board in the exact same position, no difference. I then took the SOC rom off and re-programmed, still no difference. I have checked all voltage rails within the PD controller area and there are no shorts or missing rails. The only one I can see that could be off is my p5v_s2 rail. Not sure where to progress from here?
ThanksLeave a comment:
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Hi Mon, thank you for responding. I get 25 ohms to ground on PP1V05_S2SW_VDD2HLeave a comment:
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I have a feeling this is a PD rom problem to be honest.Leave a comment:
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Macbook Air A2681 Board 820-02536 No Power - 5V 0.025A
I have an m2 air A2681 here today that is just giving 5v @ 0.025amp draw. No liquid damage or prior history of repairs. No power at all. Checked the following lines:
PPDCIN_AON_CHGR = 5V
PPBUS_AON = 12.36v
PPBUS_5vS2_VIN = 12.3v
PPBUS_3v3_S2_VIN = 12.3v
PP3V8_ON = 3.8v
PP1V05_S2SW_VDD2H = 0v
PP1V25_S2 = 0v
I have replaced U5200, R5215 & R5216. Checked ohms on both resistors. Both tested good. Little bit stumped on this one. Any help would be greatly appreciated. -
Not a problem Mon. I will let you know how I get on and hope for the best. I actually have an answer for that Mac I mentioned before with the m1 pro a2442 where the display would cut out after turning screen brightness up past 75%. It was a motherboard issue. The problem was a mosfet QP800 had corrosion underneath it. I removed and replaced it with a donor board and it works flawlessly now. So thats something good to know. i tested the original fault with a new LAS and screen but they did not fix the issue.Leave a comment:
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Hey Mon,
Yes, so on the 2.5v nand rail for pp2v5_NAND0, we have 0.22 ohms. The other nand rail pp2v5_NAND0 is 450k ohms. Im 90% sure we have a dead nand here. Now, I have spoken to someone else that said you can pull the nands from a donor board and then complete a dfu restore. Will this work?
ThanksLeave a comment:
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Hi Mon,
Hope all is well. Than you for responding so quickly. Si I will have to look into pre-programmed nands for it. I will double check our power supply now that it has been replaced. It's looking much better than it did before, however I do feel like the nands have potentially failed due to the power supply failing. I actually got an answer for that other mac I mentioned before (No clue where my post went). It was the A2442 with the screen issue where it would cut out after 75% brightness... It was an issue with the mosfet QP800. Replaced and fixed that issueLeave a comment:
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M1 pro 16" 820-02100 No power/power cycling
Hi there,
I have a 16 inch m1 pro here from another repair shop. The symptoms of this mac are no power/power cycling. I have since diagnosed this as being a nand PSU Issue - UN900. The reason being is because I was getting 12 ohms on PP2V5_NAND1 and injecting just 0.5v, the chip got red hot and burnt my hand. I have removed the chip, pulled from donor m1 pro 14inch board, reballed and tested. I now get 20v and current draw climbs steadily to 1.4 amps. However, now nothing happens. There is a blank screen with no caps lock light working. The trackpad has haptic feedback and clicks.... -
Hi Mon,
Thanks for responding so quickly. I will take a look at the pd controller wiki. I do have a thermal camera, but the chips only get hot when being used which I suppose is normal....
ThanksLeave a comment:
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820-02773 A2338 M2 13" No power
Hi guys,
Strange one here:
I have an 820-02773 with no power. It was liquid damaged prior but only a very small amount around one of the CD3217 ic's. That has since been cleaned up, but no change.
Current symptoms:
One port is giving 5v with 0 amp draw and the second port is giving 5v with slow climb to 300mah and then drops to about 0.10mah after 3 - 5 seconds.
PPBUS_AON 12.02v
PP3V3_S2 3.3v
PP3V8_AON 3.79v
P3V8AON_VSW1 3.79v
I have tried replacing the PD controllers from a donor icloud locked... -
MacBook Pro A1707 820-00928-A No power not turning on or charging
Got a very strange one here. Got an A1707 that came in dead no power. Plugged into amp meter and get 5v and then power cycles. After removing the board from the housing, I get 5v on all 4 ports with no amp draw, but it stays at 5v. I then check all rails:
PPBUS_G3H - 2.3v - Not shorted (1.8 megaohms)
PP3V3_G3H - 3.3v
PP1V8_UPC - 1.8v
PP3V3_UPC - 3v3v
D6902 - 3.3v on pin 1 & 3
I then saw these readings and thought, classic ISL9239 issue
Removed ISL and replaced with donor board. Mac powered up to 20v and drew around 300mah
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I sourced from a donor board. It was a PD controller I had laying around with other chips I had previously pulled, so unable to verify if it was from the same model or position. New type of fault for me. Never seen something like this before to be honest. Seen similar cases where the mac won't enter DFU because of a bad PD but it will charge etc... But not something like this...Leave a comment:
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Hi Mon,
I have just replaced the PD controller and the USB C port is now working! So it seemed to be PD controller related... Maybe a communication issue with the PD controller? Didn't look bad underneath? Maybe could have reused the same chip...
Al good now though. Thanks for you help though. Really appreciated!Leave a comment:
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Thanks for the help again! Yeah, I started to think this could just be a problematic PD controller or possible TBT ROM. Would it be possible for it to be caused by a TBT ROM? Or is that unlikely? I think I might end up just replacing the PD controller and see if that changes anything. Unfortunately, I need to get this job finished even if its not a fix. So won't be able to hold off until tool arrives. I will report back if this changes anything. I have seen similar things where people have not been able to enter DFU mode on an m1 mbp but the pd controller itself works just fine in terms of charging....Leave a comment:
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Hi there,
Thanks again for responding. So the current draw on the bad port will climb slowly, as if it is working. So it will start at like 5v0.3 and then go to like 0.7, then 1.3, then 2.3 and then it will just drop to 0amp draw and sit like that. The other port works just fine. The mac also works just fine and when logged in, when using the bad port it displays as a charging symbol, but will specific that the battery is not charging correctly. Tried another usb c port as well in case, but still no difference... New charger etc...
I have just ordered one of those tools...Leave a comment:
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Hey bud,
Thank you for responding so quickly to this. Yeah, I have tried cleaning out the FPC connector. This is the 13 inch m1 so only one set of usb c ports on one side. FPC connector very clean. I have check continuity from CCX pins to the test pads as well and it all seems good. A very weird one really...Leave a comment:
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MacBook Pro M1 2020 - 820-2020-A - 20V in one port and 5v in the other
Got a bit of a strange one here. Issue is that the mac powers on and charges just fine in one of the ports. When you plug the cable into the other, it will sit at 5v but still draw 2.3 amps, just like the 20v port.
Board is just like brand new, no liquid damage or anything. Has been swapped into a new housing previously though by another shop. Was given to the customer and they brought it back to them saying it wasn't charging correctly.
Checked board measurements. I have also tried the charger flipped both ways for the CCX pins, but still makes no difference.
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A2337 820-02016-A Failing DFU mode
I have a very strange issue here. Customer was using Mac one day and stopped working when they went to use it the next day. I plugged it into my amp meter and I got 5v at 0.10amp.
Checked all rails:
PPBUS_AON: 12,3 V
PP3V8: 3.79v
PP3v3_AON: 3.29v
PPDCIN_AON_CHGR_R: 5 V
The very strange part of the issue is that I left the Mac on one side for a day, came back to it and reconnected everything. Connected the DFU cable to a WS machine and connected the charger. The Mac then booted to the login screen? I then logged in and because I was after...
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