8100 Magnetek PSU - does the fan always run?

[lobust]

I bought a used PSU (Magnetek 3390-20-001) from, I believe, an 8100 to replace the dead and unsalvageable PSU from a project Quadra 800 I have.

It all works fine but the fan didn't run at all during my limited testing.

Is the fan load/thermal operated on this PSU, or is mine faulty?

 

[lobust]

I bought another identical psu and the fan runs all the time, so I guess the first one is faulty somehow. I will open it up at some point and check it out.

 

[dramirez]

it runs the fan whenever the system is turned on, right?

 

[LaPorta]

Yes, the 8100 fan normally runs the entire time the system is on.

 

[Becks79]

The PSU fan of the 8100 also functions as case fan, and exhausts hot air from the peltier cooler for the CPU, so it has to run all the time. So if it doesn't run, then it's clearly faulty.