Thermal sensors in AV gear
 

I've got a Denon 5-channel receiver that has a fan on the heatsink. The
fan doesn't run and the unit overheats, unless I short the heatsink fan
test pins -- then the fan runs at low speed and the heat is controlled.

On the heatsink are a couple of temperature sensors that look like
junior-sized TO-220 transistors, except they're grey and have two wires
for legs. The two of them measure differently (resistance vs. heat), but
I don't know which one (if either) is faulty.

How do I test these things, and where do I get replacements? The numbers
on them don't look much like part numbers.

thanks, Isaac

Thermal sensors in AV gear
 

isw wrote:
I've got a Denon 5-channel receiver that has a fan on the heatsink. The
fan doesn't run and the unit overheats, unless I short the heatsink fan
test pins -- then the fan runs at low speed and the heat is controlled.

On the heatsink are a couple of temperature sensors that look like
junior-sized TO-220 transistors, except they're grey and have two wires
for legs. The two of them measure differently (resistance vs. heat), but
I don't know which one (if either) is faulty.

How do I test these things, and where do I get replacements? The numbers
on them don't look much like part numbers.

thanks, Isaac
they are either PTC or NTC.. positive or negative Temperature
coefficient devices.
they both should be with in 10% of each other at rome temperature..

i am only taking a guess here. you could have a silicone type
one also.



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