Hi Everyone,
I have been looking to find some information on a thermistor that is used in a Technics SE-A100 amplifier. The component in question is TH151. There is no resistance value or part number listed in the service manual.
Can someone help me identifying this part ?
I have been looking to find some information on a thermistor that is used in a Technics SE-A100 amplifier. The component in question is TH151. There is no resistance value or part number listed in the service manual.
Can someone help me identifying this part ?
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Hello,
There's a nice person in Germany who posted some detailed pictures here. As far as I can tell, Technics decided to replace R153+Th151 combo with a 470 Ohms(?) resistor. You can measure that resistor for sure and, knowing from schematics that R153 is 1.8KOhms, you'll have thermistor's value at 20*, as @MAAC0 said.
Regards,
Cosmin
There's a nice person in Germany who posted some detailed pictures here. As far as I can tell, Technics decided to replace R153+Th151 combo with a 470 Ohms(?) resistor. You can measure that resistor for sure and, knowing from schematics that R153 is 1.8KOhms, you'll have thermistor's value at 20*, as @MAAC0 said.
Regards,
Cosmin
Hi MAAC0,
thanks again for trying to help.
So I guess you measured something with the circuit intact. I am not sure if this measurement would be valid.
What was the temperature at the time you took this measurement ?
Can you remeasure at two additional temperature points ?
Ideally, the thermistor is measured by itself without the circuit around it.
thanks again for trying to help.
So I guess you measured something with the circuit intact. I am not sure if this measurement would be valid.
What was the temperature at the time you took this measurement ?
Can you remeasure at two additional temperature points ?
Ideally, the thermistor is measured by itself without the circuit around it.
So both are in parallel. 1800 in parallel with 640 gives 472 Ohm.
I would try a 630 or 640 Ohm thermistor.
So it seems they may have over compensated in the A100.
Thanks for your help.
Thanks for your help.
Can omit... they did in SE-A5000 (re run A100)
Hi all,
I think that position of VBE multiplier made Technics to not use the thermistor in the final product. This transistor is not directly placed on heatsink but on a prolongation of it... and so, is placed in an area (volume in fact) which otherwise would be covered by thermistor. If I'm right, Th is not needed indeed.
Regards,
Cosmin
I think that position of VBE multiplier made Technics to not use the thermistor in the final product. This transistor is not directly placed on heatsink but on a prolongation of it... and so, is placed in an area (volume in fact) which otherwise would be covered by thermistor. If I'm right, Th is not needed indeed.
Regards,
Cosmin
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