820-2915 no chime

[Chuck60]

Hi I have a board that doesn’t chime. Audio circuit is fine. all my voltages are present and have fan spin. But, no mouse activity. The mouse blinks only once in start up. I checked for cpuvcore voltage it’s 12.5 and resistor R7402 is 90.7k I guess my question is that On pin 1 of R7402 what is the correct voltage that I should have? Can this resistor be failing under a load and still giving me a good reading? This has happened to me before

On board 1- I have 12.3v
2- I have .9v
Neither of these turn on :/ look in the datasheet I would expect to see somewhere in the 12v range but I preferred to ask a expert. Thank you for your time

 

[2informaticos]

Do not expect a chime, if the board doesn't boot.
You forgot to mention VCORE voltage.

TON pin of U7400 drops to 0.5V aprox, when it generates VCORE.

 

[Chuck60]

Pin 2 :
L7530 - PPVCORE_SO_CPU_PH3_L=1.16v
L7520 - PPVCORE_SO_CPU_PH3_L=1.17v
L7510 - PPVCORE_SO_CPU_PH3_L=1.16v
L7550 - PPVCORE_SO_CPU_AXG_L =0v

ALL_SYS_PWRGD= 3.4 at 7974
R7974=0 ohm
CPUIMVP_AXG_PGOOD=0v - .9v pulsing almost like a charging and discharging of a capacitor. I look at the schematic and is says it’s a unused PGOOD signal.

 

[2informaticos]

When this board really boots, you should note a drop on VCORE, like 1.15V to 0.75V.
First check other DDR module, on each slot.
Try PC3-10600, 8500 is not good here.

Try new BIOS, if still same symptom after all...

 

[Chuck60]

All good issue resolve a resistor and cap with broken trace by isl for u8900 gpu
Thank you for your help