used surge protectors

[Vgkid]

I have a option of getting a used isobar either for free or cheaply. Since it is used in working condition( but unknown amount of hours are on it). What would need to be replaced, or should I use it directly. Might be an isobar ultra 12.
Or should i just skip the idea, my current set of phillips are to finicky with the safety shutters.

[sarepairman2]

I think the MOV bank is the thing most likely to get worn down.

[Vgkid]

Thanks, thats what i figured.

[Kbeistline]

As I understand the theory of Metal Oxide Varistor's (aka. fused resistor). As a circuit is powered the initial voltage spike causes the crystalline structure to heat up and increase resistance thus reducing the current delivered to a load. As the voltage level equalizes the crystalline structure cools and recombines thus reducing its resistance and allows more current to flow. If the initial voltage spike is greater than the MOV's max rating it will fail. Depending on how massive the spike is, it can fail rather spectacularly! I have not read any specifics on their meantime to failure, but can attest to the weakening of the crystalline structure causing them to fuse open. Over time, repeated normal spikes will weaken the crystalline structure causing it to merely open circuit, thus providing a valuable load protection. In the case of a nearby lightening strike, even a brand new MOV will 'pop' and may or may not provide enough protection for a given load.
*SAFETY-1st* Make sure you completely understand how lethal repairing mains powered equipment is before attempting any repairs.
 Just checked Mouser.com, lists MOV's priced between 50¢ - $5 USD.