I actually have 3 820-3437 boards that have the exact same symptoms:
1. Green/orange light, fan spins for ~6 seconds, then stops, then turns on and spins continuously until unplugged. No cycling, even with SPI ROM chip removed.
2. Boards all have VCORE and CPU gets appropriately warm.
3. No shorts detected on any rails.
4. No LCD activation or chime.
5. SPI ROM resistors/traces all fine. Continuity fine as well.
6. PM_S0_PGOOD is present on all at U1950.
7. PPVRTC_G3H is present on all.
I'm at a loss on these. It's really strange to have 3 in a row with the exact same issue once repaired from liquid damage. I've already cleaned the boards, and have tried a clean BIOS on one of the boards, but it had no effect. On the other 2, I did swap the BIOS chip with the clean BIOS into place JUST TO SEE if I get a delayed chime (I know there would be issues if I left the chip in place, but I only wanted to see if I could get *any* chime or activity on LCD).
Any direction would be appreciated.
1. Green/orange light, fan spins for ~6 seconds, then stops, then turns on and spins continuously until unplugged. No cycling, even with SPI ROM chip removed.
2. Boards all have VCORE and CPU gets appropriately warm.
3. No shorts detected on any rails.
4. No LCD activation or chime.
5. SPI ROM resistors/traces all fine. Continuity fine as well.
6. PM_S0_PGOOD is present on all at U1950.
7. PPVRTC_G3H is present on all.
I'm at a loss on these. It's really strange to have 3 in a row with the exact same issue once repaired from liquid damage. I've already cleaned the boards, and have tried a clean BIOS on one of the boards, but it had no effect. On the other 2, I did swap the BIOS chip with the clean BIOS into place JUST TO SEE if I get a delayed chime (I know there would be issues if I left the chip in place, but I only wanted to see if I could get *any* chime or activity on LCD).
Any direction would be appreciated.
Compare Vcore and AXG and VCCIO on diode mode with a known good board.