Do NOT re-use varistors :D

[Behemot]

Not a good idea, there are certain components which are not good to re-use

Wanted to spare a buck and re-used two. One of them exploded within 5 seconds atfer computer start. Uff, good that I have started to cover them with spaghetti insulation (is this the right term? came out from dictionary), otherwise the PCB would be much more darker

[budm]

Re: Do NOT re-use varistors

Are the MOVs the same voltage rating as the old one?

[goodpsusearch]

Re: Do NOT re-use varistors

Well, I do that all the time

[Evil Lurker]

Re: Do NOT re-use varistors

Yup trick as I understand is to check their resistance with a DMM before installation, if that checks out then attach them to normal mains working voltage and use a temperature probe to check for leaks... a leaky MOV will heat up just like an overloaded resistor... thats why about every surge protector I have seen uses thermal fuses next to their MOVs.

[shovenose]

Re: Do NOT re-use varistors

I've reused these a lot and never had any problems.

[Behemot]

Re: Do NOT re-use varistors

Well MOV's as well as resistor have limited value of spikes they can handle. You never know how many they supressed before, so even in theory this is really not good thing to do. They can also handle just a few of them and blow in a week.