820-4652 fast fan

Kyle93

Active member
This imac arrived with fan spinning fast and running slow.

memory proximity 2 sensor was at 126C in HW monitor.

Replaced Q5675 but no change. I do not see where else proximity 2 appears in schematic.

What should be checked next?
 

Kyle93

Active member
No history, just randomly started fast fan spin one day. No SSD upgrades since this came with a fusion drive
 

Kyle93

Active member
it will only pram reset 2 times in a row. After the second reset fan starts to spin fast before OS even starts loading, internal or external.
 

Kyle93

Active member
Not sure why but there was a internal HD sensor installed on main drive but fan still spins fast even with this disconnected.
 

Kyle93

Active member
When the custom sensor is connected or not, the fan spins fast.

Memory proximity 2 128C

HD bay 1 249C

HD bay 2 129C
 

Kyle93

Active member
Contact on LCD temp sensor looked fine. Disconnected and reconnected just to be sure but still fast fan.

Would you suggest replacing LCD temp sensor next?
 

2informaticos

Administrator
Staff member
Replace it, if possible.
Check continuity for its cables/contacts.

Actually, is there any disk attached on SATA port?
 

Kyle93

Active member
There is the main 1TB rotational drive and a 128GB SSD drive on the main board. If both are disconnected, fan still spins fast.

Would have to order LCD temp sensor if need exact one , just do not like throwing parts at it when not sure what it is.

Tried a LCD temp sensor from a 21" 2015 LCD but no change either
 

2informaticos

Administrator
Staff member
Tied together pins 10/11, or 11/12 on the HDD SATA connector (on the disk directly) and try again connecting it.
 
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