[SOLVED]820-3115 Boot loop no chime

[ALB-Repairs]

Got a 820-3115 thats so very nearly posting, But just as it initialises RAM the machine turns off and starts again. The CPU core drops to 0.8V as it should just before post.
It had a tiny amount of liquid damage near the SPI, but ive reflashed it and no difference was noted. If the ram is removed the system remains on and gives a single beep.

 

[dukefawks]

Is this with or without an LCD connected?

 

[ALB-Repairs]

Issue is without the LCD connected, board out, no peripherals connected/ board only.

 

[dukefawks]

Could be many things. Check corrosion under SMC/PCH and around clock chip.

 

[ALB-Repairs]

Ive checked all of that, No signs of corrosion, i ultrasonic-ed it, no change, ive now reflown the SMC and PCH, again no change.

 

[dukefawks]

I would look around U7400 and the FETs. AXG voltage coming on too?

 

[ALB-Repairs]

Missing R7554, Assume some moron had ripped it clean off, not something i was looking out for.
Solved, Thanks Duke