Lenovo Legion 5 Pro 16ACH6H Type 82JQ – Shorted EC Chip

PL6201 = 3.34v, PL6202 = 5.16v.

Close the jumpers PJ6205, PJ6207 and measure the resistances on all pins of the KBC chip in reference to the coil PL6202.
It's not necessary to specify all the measurements, only specify the resistances that are less than 2kΩ, if any.

All of the ground pins (1, 27, 49, 75, 91 & 104) have a resistance of 1.14kΩ. Everything else is over 2kΩ.

MendUsThis napisał(a):All of the ground pins (1, 27, 49, 75, 91 & 104) have a resistance of 1.14kΩ.

But you previously measured a resistance of about 5kΩ on this coil in reference to ground:

MendUsThis napisał(a):With the damaged chip, the resistances are as follows:
PL6202 = 5.44kΩ

MendUsThis napisał(a):With the new KBC, resistances to ground are as follows:
PL6202 = 5.4kΩ

Yes, measuring PL6202 resistance to ground, I'm getting around 5.4kΩ. I also have the same resistance to ground from PJ6207, but from any ground pin on the KBC with reference to either PL6202 or PJ6207, I have 1.14kΩ. I have rechecked twice, but the results are the same.

MendUsThis napisał(a):but from any ground pin on the KBC with reference to either PL6202 or PJ6207, I have 1.14kΩ.

Check this resistance again with the revered polarity of the test leads.

Ah yes, of course, I see my error
I should be using the Black probe on the KBC ground pins, so I'm measuring resistance of the coil to ground, just as before. It is now 5.4kΩ

Remove the coil PL6202 from the board. Set your laboratory power supply to 5V and limit the current to 0.2A. Connect it to the system side "+5VALW_P" power rail.
What electrical current flows from the laboratory during the test?

Current goes straight up to the 0.2A limit. Voltage is initially 3.7v for approximately 1 second and the begins to fluctuate rapidly between 4.5 and 4.7v.

Remeasure the resistance to ground on coil PL6201 and on pin 3 of chip PU6201.

PL6201 = 2.78kΩ.
PU6201 pin 3 = 376kΩ.

Repeat the test from the post #28, but this time with a current limit set to 0.5A. Does the voltage reach 5V in this case?
Also remeasure the resistances from the post #30 after the test.

Voltage is now stable at 5v. Current draw is 222mA. The resistances are the same as in post #30.

Solder the coil PL6202 back to the board. Open the jumpers PJ6205, PJ6207 again and connect the power supply to the board.
Remeasure the voltages to ground on the coils PL6201, PL6202. If both voltages are fine, close the jumpers PJ6205, PJ6207 and check the voltages on this two coils again.

Voltages on PL6201 & PL6202 are fine. As soon as I connected the power supply, the board powered up. Green power led is illuminated and I can feel that there is a little bit of heat in both the APU and GPU. Also, the KBC has survived this time
I assume that I can connect the board back into the laptop, or is there further testing to be carried out?

If you are in doubt, you can replace the chip PU6201 (RT6585CGQW) to make sure. It's possible that something happens to this chip from time to time and a voltage surge occurs at the output, damaging the KBC chip.