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I started gradually with voltage: on PPBUS_G3H I putted 10A and 1V, then I tried with 2A and 10V and found the short. on PP5V_S4 I putted 5V and 1A, no more than this. I thought that is there maybe still a short somewhere, could be?

Thanks informaticos, injecting voltage on that line like you explained on that post, I found who was the responsable of the short on PPBUS_G3H. The responsable was U8050, I replaced it and now I have not short to ground on PPBUS_G3H. Now the voltage on PPBUS_G3H is not stuck at 13.1V how it...

I removed F7000 ad I still have short only on Capacitors, from C7090 to C7099. It means now that the short is not on PPVBAT_G3H_CHGR_REG, but it comes from PPBUS_G3H. The value on the short is 95.3 ohm. Should, at this point, try to inject voltage or is maybe better go ahead with the isolation...

Hi to everyone, I am facing a short circuit issue on a circuit board and would like to share my situation to seek advice and suggestions from the community. I have identified the short circuit on the PPVBAT_G3H_CHGR_REG line, and I have proceeded to isolate the circuit by removing R7060 and...

Hi, I find myself in the same situation as yours, and I truly share your passion for wanting to learn. I, too, am figuring out how to tackle issues by reading schematics and diagnosing faults, but theory often falls short when it comes to real-world application. I've taken various courses and...

I've tested 5 different BIOS files (2 sent by you + 3 found on the internet), but none of them allows the MacBook to start up. I compared the area near the BIOS with an identical non-functional board, and all the components are present; there is no missing component in the area surrounding the...

I initially did not inform you that I had two similar BIOS chips. What I did was desolder the original BIOS, program the second BIOS (the non-original one), and then solder the second BIOS onto the board. Meanwhile, the original BIOS still contained its original bin file. After soldering the...

Thanks, I flashed the BIOS you sent me. Now the tension of PPVCC_S0_CPU on C10G1 start from 0V up to 0.785V and remain stable at 0.785V. If it can help, I noticed also that the tension on PPVCCGT_S0_CPU is now present with 1.05V. I still don't see the Apple logo on screen. I'am thinking that...

No, internal caps lock led does not react at all

Yes, on PPVCC_S0_CPU after some seconds the Voltage drops from 1.15V to 0.64V and remains stable on 0.64V, but I still don't see the Apple logo on screen. There is also not audio when it boot up. What else could I test?

@2informaticos Apologies for the delayed response; the holidays kept me busy. Returning to the issue: unfortunately, I don't have an identical and functioning board to compare values. After checking the main lines and confirming their functionality, I also ruled out an issue with the internal...

If I were to power the PPVCC_S0_CPU line using the bench power supply to detect any shorted components with a thermal camera, do you think it would cause any damage? Or could it be a potential solution?

I checked, they are not shorted to ground.

I did, but it does show nothing on the screen. Now I noticed that for the second time the LB190 blow up (See here). I don't know why it has to happen. I still don't know which test could I try... Any idea?

I tried external video via display port and via HDMI for both does not work. USB activity works because I connected a keyboard with backlight ant it works. Is there something else I can test?

I've now tested the board directly on the bench. The board draws 0.980A, and the voltage on PPVCC_S0_CPU is 1.15V. However, after just 10-12 seconds, the board starts drawing 0.488A, and the voltage on PPVCC_S0_CPU returns to 0.65V. I tested also VCC on U6101 and on U6100 and there are 3.3V...

Yes, I flashed the bin file you linked. Now, after soldering the chip back onto the motherboard, I reassembled the board in the case. Upon powering it on, I noticed the fans start spinning, the voltage remains at 20V, while the current rises and stops at 2.840A (See here). However, upon turning...

No, unfortunately, I forgot to back up the BIOS. I've tested Ventura, High Sierra, Monterey, Big Sur, Catalina, but despite everything, I received the message that it's not possible to update after installing the operating system. So, the system never started. I ask for your forgiveness, but...

Thanks for the help, I don't have the green LED on the Caps Lock, but the fans spin at maximum speed. After about a minute, they restart and continue this cycle indefinitely. Here are the voltages on the following lines: CPUCORE_PWM1: 0.369V CPUCORE1_GL0: 4.686V CPUCORE2_GL0: 4.694V...

Hello everyone, I have a 820-00923-A board that used to boot without any issues before I flashed the BIOS. After programming the BIOS chip with the CH341A programmer, the board did not power up anymore. So, I took the schematics of the board and started checking the power aliases. I verified...