MT-170

[Danndad]

Has anybody got any info on a MT-170 thermistor please, not sure if it's japan made.

Danndad.

[joebog1]

All I could find is that its a 170 degree C motor protection thermistor.

https://rewindsensors.com/mod_pdf/rewind...istors.pdf


Joe

[Mike Watterson]

What is it in?
What part of the circuit?

Then it's possible to know an alternative.

[Danndad]

Thanks for looking Joe.
Mike, I will post a part of the circuit diagram if I can later, its in another version of this.

https://www.radiomuseum.org/r/standard_s...h_741.html

[Mike Watterson]

Likely then to stabilise bias current on a Germanium transistor based audio amp output.

[Danndad]

Sorry for the delay, here is a part of the circuit that this thermistor is in. I am unsure of what its value should be at room temp? What happens is the current on the output pair rises after a while. I've replaced a couple of bad transistors in the audio section and replaced the preset as it was very unstable.

   

[Mike Watterson]

If R24 is 150 Ohms, then it might be between 500 and 2000 Ohms when cold and maybe 200 to 500 ohms when O/P warms. Usually mounted on the heat sink.
You can test it by putting it on the Ohms meter out of circuit at about 18 °C ambient and heating it in your hand to more than 30 °C.