Bad Resistor?

[Bill Bergman]

Can a resistotr be bad and still give the right value reading on a DMM?
I noticed a slight off-color ring around a certain resistor that's not a regular color band in a circuit that's not working.

[niftydog]

potentially. (ha ha ha... ha... ahhh forget it.)  :?

Well, I suppose it's possible, but maybe more prevelent in high voltage or highly sensitive circuits.

To properly check a resistor it must be removed from the circuit.

discolouration can be a sign of excessive heat, but resistors are pretty hardy beasts.

[Bill Bergman]

Thanks.
Yeah it was overheating but hadn't burned out.....yet.

[Eric H]

Thanks.
Yeah it was overheating but hadn't burned out.....yet.

Bill, unless that overheating was a construction error --never to be repeated you might want to replace it with a larger wattage-rated one (like a 1watt instead of 1/2 watt)

[Bill Bergman]

Thanks Eric!
It is due to an error. I've got 150vdc coming of of the grid pin of a power tube. It's supposed to be 0vdc. :?