820-3437 Doesn't spin up and down at startup, just spins up like a 2015.

bjf

Member
This board had some liquid damage in the usual U1950 area and over to the SMC area. Nothing crazy, just cleaned it up and replaced some components. It appears to be working normally and passed ASD but when it starts up it doesn't do the fan up and down 3 times, it just spins up and works like a 2015. Any idea what might be happening?
 

2informaticos

Administrator
Staff member
Reball SMC, if corrosion seen in its area.
You can also try new BIOS.
It should restart 2 times only when charger is connected first time; if battery has been disconnected before.
 

bjf

Member
Ok, thanks, I tried reflowing the SMC and cleaning up anything else I could find but it was still not spinning up properly. I'll just sell it as-is rather than spend the time swapping an SMC. For the record, it didn't have a lock. I had done a PRAM reset with no change. Once I have someone assemble it I'll have them do an SMC reset. Maybe that will help. Either way, thanks for the tips.
 

2informaticos

Administrator
Staff member
Once battery is removed, SMC reset is done.
SMC reset procedure is valid for un-opened machine, where the battery still maintains SMC_RESET_L high.

Once is properly powered off, 3437 board starts like any other board; w/o any previous attempt.
 
Top