Operating temperature for transistors

 

Bronze Member
Username: Mike_6289

Post Number: 14
Registered: Feb-05
I have been thinking of getting temperature sensors and sticking them to the transistors in my amp so that I know if I will blow them or get them damaged by heat. I know it sounds stupid, but its a 30 year old receiver and would be hard to find the right FETs to go in it.

So.... what should I set the "alarm" temperature to?

thanks
 

J. Vigne
Unregistered guest

Are you going to take the cover off the receiver and monitor the temperature constantly? How loudly do you listen?


 

Bronze Member
Username: Mike_6289

Post Number: 15
Registered: Feb-05
Well... yes I am going to remove the cover, install a computer drive bay thingy that youre supposed to use for video card temperatures and CPU temperatures. I listen fairly loudly, it shakes the floorboards and rattles the windows.
 

J. Vigne
Unregistered guest

Look at the manufacturer's name on the output transistors and find the information from them. I would be suprised if something designed for video cards will have the range needed for FET's.

I would tell you what you are concerned about is of minimal value in determining when or if the outputs will go out. A transistor is more susceptible to the heat and cool cylce of use than any one temperature range. As time goes by component parts change value and the likelyhood would be greater that a bias resistor or a cap will go out and take the outputs with it. Unless the bias resistors have changed value dramatically over time, the transistors will be running at the same temperature they have for the last few decades. All components have a limited lifespan and monitoring the heat is not going to be very beneficial unless you are committed to turning the unit off when you see the heat rise. If your listening habits haven't damaged the amp in this time, it is unlikely you would do so now. If your concern is heat, you would do better to install a ventilation fan that will keep the temperature down as opposed to seeing what the temperature is.


 

Bronze Member
Username: Nuck

Parkhill, Ontario Canada

Post Number: 33
Registered: Dec-04
If the cover is off anyhow, release the transistors and reapply heat sink compound, note the info on the componants like Vigne says there will be lots of newer parts as replacements, check the nec website, and cross them. The parts are probably just cycle worn, but then again, so am I.

Cheers
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