After fan stops pulling about 24ma from the charger.
Going down the power rails I have everything till PP5V_S4RS3, on U7501 it is 5V
while fan spins, then down to zero when fan stops on pin 2. It looks like something
stops telling it to turn on. Any suggestions?
ALL_SYS_PWRGD goes to 3.3v then zero on pin 1 of U1950
PPVCC_S0_CPU on R7320 pin 2 peaks at 1.8v then zero
Both come up with fan spin, then go to zero when fan shuts off.
Just to make sure I am saying this correct, the fan spin and the voltages come
up when I connect charger, then about 1 second later the fan stops and
the 2 above voltages go to zero. At this point the voltages on the rail page above
PP5V_S4RS3 are all correct and present. Nothing changes that I have
found once the fan spin stops. If I disconnect/Reconnect the charger I get the 1 sec
fan spin then back to steady state until I disconnect the charger again. There
is no cycling or any of the voltages not present going above zero again.
No history, I wish I had stuff brought in for repair, but I am learning on
boards listed as for parts or repair on ebay so I am probably buying donor boards .
I could find no liquids or corrosion on the board and no sign anyone had tried repairing it.
Found bad pad and trace, ran jumper wire . The connection
between R7425 and pin 15 of U7400 was gone. Not really
corrosion but pad looked a little tarnished, scrape the black
coating off trace and copper looks like melted away.
I now have continuous fan spin, pulling about .6 amps but no chime or
display output. Back to seeing what point it fails now.
Thanks for help.