I had the exact same problem with my 8970B
Took the old fan out and placed it in the bin - no need to try to make it quiet. Even from new it is to noisy
In Europe it is easy to get hold of Noctua fan's, they are silent
The 8970B has the power supply near? the fan, so I took the +15V rail and added a small "Fan Conrtroller" to make in even more silent
I never use my equipment in higher than 25¡ãC ambient
The sensor for the fan controller was placed at the heat sink, which I found was the hottest place
Been running for years now
The original fan was a?
ETRI - 99XW 0182 000
Which I replaced with a?
Noctua - NF-A9 PWM (I did not use the PWM signal)
The fan controller is just a LM2940T regulator with a resistor and a thermistor
/Hans
? ? ??
