[James Romeyn]

Fan switch in this receiver appears to have two thresholds: input voltage and preamp gain setting.  I want to disable the fan because of noise.  Three of six power amp channels drive only surround speakers. 

I'm unconcerned about damaging the amps because the receiver shuts down when stressed.  After unplugging the fan the receiver shuts down past a low gain setting even with the amps unused.

How do I determine an appropriate dummy load for the fan circuit?  The fan has three conductors. 

Tx. 

 

     

[jcotner]

The detail you provide is limited but you could measure the current through the fan
and determine a load resister from that. Since you have 3 leads using a meter
to measure current will tell you how to configure legs to be loaded.
The amp shutting down could still be from thermal protection. Things do generate
heat even at idle. So even putting a load in place of the fan may not give you
the desired result. I do have doubts that the electronics actually sense that the
fan winding are connected.

[James Romeyn]

Thank you.  You're probably correct.  I'm easily confused with higher numeric negative SPL indicating less output. 

It's strange having the fan switch on even using no power amps (though there are speakers connected to the three surround channels). 

[JohnR]

Depending on the specifics of the fan, you may be able to replace it with a "low flow" version. The one I did in my QSC amp is rated about half the flow rate and is much quieter.