Repair help wanted for Realistic HP-100 Electrostatic Headphones

[HIPCHECK]

Need help finding a part to replace a 3.3 ohm PTH variable resistor. Is this a MOV, PTC, Thermistor? I do not know what a current replacement part would be.

Thanks for the help!

Steve

See pic:

 

[chinsettawong]

The burnt part looks a lot like a high voltage capacitor. If you look carefully, you should be able to read its value.

Wachara C.

 

[HIPCHECK]

I have a schematic on the owners guide. It has no markings but is listed as a 3.3 ohm PTH has a resistor symbol with circle around it.

 

[firechief]

My guess is Thermistor, they are rated in terms of resistance. There are some 3.3 ohm ones for sale at DigiKey but not in the same package. MOV's "metal oxide varisistors" are rated in terms of voltage and current. This page might help shed some light on the subject.
Thermistors - PTC | Digi-Key
Is there a way to scan and post the schematic?

 

[agdr]

It is a PTC (positive temperature coefficent) thermistor, from the schematic here

AudioKarma.org Home Audio Stereo Discussion Forums - View Single Post - Realistic HP-100 Eletrostat

which is post #13 in this thread

Realistic HP-100 Eletrostat - AudioKarma.org Home Audio Stereo Discussion Forums

The third part down on this list from Mouser might be a good choice, without knowing the specifics of what is coming out of your speaker terminals. The rating is (3.3R) 60V and 4A, which should cover a lot of amps

Mouser Electronics - Electronic Component Distributor thermistor

95 cents and in stock...

http://www.mouser.com/ProductDetail/Murata/PTGL09AS3R3K4B51B0/?qs=sGAEpiMZZMsFah5lC2HR3Vz%2fPXOufO9UcmBLKDCK%252bk0%3d

Suggestion: if it were me, I would buy two and replace the one on the other channel too. Since this one went the other probably won't be far behind (age), plus they will match.

Good luck!

 

[HIPCHECK]

Thats awesome, the original schematic listed that part as a PTH I guess a older description for the PTC. That is what I was looking for, Thank you!

Steve

 

[billjames]

The wires are very thin and break easily. It can be fixed.
here's a step by step tutorial