Hi Guys noob here on electronics repairs but have been reading a lot of posts on here for similar boards and issues and have progressing quite a bit.
A bit of history on the board, this is a water damaged Mb, initially I cleaned the board and found that there was a Short on +19 Vb rail (0.6ohm).
I injected voltage (1V) and used thermal cam on the 19 Vb rail and found a cap (PCV97) shorted cap near PUV4. I removed it and short was gone. Attempted power no response, checked 19V rail and shorted again. Injected 1V again and found a cap near PCW52 shorted, removed. And short is gone.
Plugged battery and charger in, battery charging PU301 warm, charger light on
Power button pin 3.3 V
Tried to power on, fan spin, light on, turns off within a couple of seconds.
I noticed I would only have +3VALW and +1.05VALW momentarily after Power button was pressed ( which seems correct looking at power sequence schematic). PU1101, PUW1 and PCH warm up for a few seconds
I read on another post about thermal protection circuitry near DB1 so i have jumped DB1 and removed PB14 and PB13.
Pressing the power button give the same results quick fan spin, but now i have constant power at +3VALW and +1.05VALW. PCH is staying warm, chip looks to have uniform heat, holding at 23 C, is this a bad PCH? All chips mentioned before pulse heat once when power button is pressed.
Now the I have
Checked all rails 19V (xxK ohms), 3V (xxK ohms) , 1.8V (xxKohms), 1.05V (33ohm) no shorts.
Voltage on
PQB11 19.5V - source and gate
PQB12 19.5V on gate and 25V on drain
No shorts on PQZ1- PQZ4
PLZ2 - PLZ4 - approx 3.5 ohm
PLZ1 - 15 ohm
+3VLP , +5VALW, +3VALW, 1.05VALW and 1.8VS all reading correct voltage
One thing i found is 0V on DRAM_RESET ?
Is the PCH toast or should i keep trying?
TLDR
Fixed all shorts on all rails. Have jumped Db1 and removed RB13/14, only momentary power, PCH stays warm when AC plugged in.
Schematic and boardview ---> https://www.badcaps.net/forum/showthread.php?t=120015
A bit of history on the board, this is a water damaged Mb, initially I cleaned the board and found that there was a Short on +19 Vb rail (0.6ohm).
I injected voltage (1V) and used thermal cam on the 19 Vb rail and found a cap (PCV97) shorted cap near PUV4. I removed it and short was gone. Attempted power no response, checked 19V rail and shorted again. Injected 1V again and found a cap near PCW52 shorted, removed. And short is gone.
Plugged battery and charger in, battery charging PU301 warm, charger light on
Power button pin 3.3 V
Tried to power on, fan spin, light on, turns off within a couple of seconds.
I noticed I would only have +3VALW and +1.05VALW momentarily after Power button was pressed ( which seems correct looking at power sequence schematic). PU1101, PUW1 and PCH warm up for a few seconds
I read on another post about thermal protection circuitry near DB1 so i have jumped DB1 and removed PB14 and PB13.
Pressing the power button give the same results quick fan spin, but now i have constant power at +3VALW and +1.05VALW. PCH is staying warm, chip looks to have uniform heat, holding at 23 C, is this a bad PCH? All chips mentioned before pulse heat once when power button is pressed.
Now the I have
Checked all rails 19V (xxK ohms), 3V (xxK ohms) , 1.8V (xxKohms), 1.05V (33ohm) no shorts.
Voltage on
PQB11 19.5V - source and gate
PQB12 19.5V on gate and 25V on drain
No shorts on PQZ1- PQZ4
PLZ2 - PLZ4 - approx 3.5 ohm
PLZ1 - 15 ohm
+3VLP , +5VALW, +3VALW, 1.05VALW and 1.8VS all reading correct voltage
One thing i found is 0V on DRAM_RESET ?
Is the PCH toast or should i keep trying?
TLDR
Fixed all shorts on all rails. Have jumped Db1 and removed RB13/14, only momentary power, PCH stays warm when AC plugged in.
Schematic and boardview ---> https://www.badcaps.net/forum/showthread.php?t=120015
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