68kMLA Classic Interface

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identification of a weird resistor (thermistor)? on a mac classic

Posted by: gkmaia on 2020-06-09 11:51:07 I got a fried resistor on my classic. I imagine that is a thermistor but not sure. From the schematics I would say it is a 20ohm at room temperature. But unsure of the watts. Can any one give me a light on that one. Another question. If I replace the resistor with an ordinary 5w 5ohm resistor just for the sake of testing the board. Will that be fine? just for testing... If that is a thermistor at 20ohms it provide almost no resistance and is there just a safety device to cut current in case of a surge. is that correct?

Posted by: IlikeTech on 2020-06-11 00:32:13 I think this is what would be called an NTC thermistor.  It limits inrush current when the machine is powered in.  It then heats up and the resistance drops to almost nothing.  I wouldn’t replace it with a fixed value resistor, although I’m not sure what would happen if you did.

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