overshoot
Member
Hi,
I'm trying to repair that board that had liquid damage on top area of the board, near the keyboard backlight connector, CPU mosfets and at the back on the capacitors on PPBUS_G3H.
Originally that board was giving no light on the charger and PPBUS_G3H was at 0.8V
Once the PP3V42_G3H regulator was replaced, the charger light came back and PP3V42_G3H was a stable 3.3V.
Then, I ended up having to replace the ISL chip to get PPBUS back and the board came on.
I gave the board an IPA cleanup and put the computer back together, tested it overnight to find the board dead again in the morning.
Once again PP3V42_G3H was at 2.2V.
Heating the area where the 3V3 regulator was, the voltage went back to its normal operating value of 3.3V and once again the board started up.
From that, I decided to replace every capacitors near the regulator, even the ones at the back of it, on the other side of the board.
I left the regulator I've replaced untouched since it appeared to me that it wasn't the problem.
Once again, left the board overnight and same problem in the morning.
I am assuming if heating the 3V3 regulator area brings back the right voltage, it has a failing capacitor close by?! But how close I guess the question is.
The board was capable of running under load but went to sleep, cooled down, then the voltage went down as a consequence I believe.
Any idea what I could be looking at next?
I'm trying to repair that board that had liquid damage on top area of the board, near the keyboard backlight connector, CPU mosfets and at the back on the capacitors on PPBUS_G3H.
Originally that board was giving no light on the charger and PPBUS_G3H was at 0.8V
Once the PP3V42_G3H regulator was replaced, the charger light came back and PP3V42_G3H was a stable 3.3V.
Then, I ended up having to replace the ISL chip to get PPBUS back and the board came on.
I gave the board an IPA cleanup and put the computer back together, tested it overnight to find the board dead again in the morning.
Once again PP3V42_G3H was at 2.2V.
Heating the area where the 3V3 regulator was, the voltage went back to its normal operating value of 3.3V and once again the board started up.
From that, I decided to replace every capacitors near the regulator, even the ones at the back of it, on the other side of the board.
I left the regulator I've replaced untouched since it appeared to me that it wasn't the problem.
Once again, left the board overnight and same problem in the morning.
I am assuming if heating the 3V3 regulator area brings back the right voltage, it has a failing capacitor close by?! But how close I guess the question is.
The board was capable of running under load but went to sleep, cooled down, then the voltage went down as a consequence I believe.
Any idea what I could be looking at next?