Need a replacement for this "Inrush current limiter"

[K3mHtH]

Hey everyone,
I'm repairing an amplifier and one of the components looks shot (picture attached). In the schematics, it is referred to only as an "INRUSH CURRENT LIMITER" with a value of "CL30". Digikey has part KC003L-ND that is an inrush current limiter with a manufacturer part number of "CL30" - all that sounds very good, but I don't know if that's just a coincidence.

The component in the amp itself has "025 081" on it as the only markings. It seems that there are many inrush current limiters with different specs.. help!

[HalfSpace]

Hi K3mHtH,

This component may have failed due to fatigue or there could be another fault in the amp which caused it to fail. Can you post up the schematic of the amp and what the fault is with it?

HalfSpace 

[Seekonk]

Don't you have a junk box?  These are very non critical items.  Sometimes I just replace them with a couple ohm resistor.  Only critical use for them is in old CRT TVs where they operate the degaussing coil.

[Smokey]

That is most likely an NTC resistor.

http://www.ametherm.com/
http://en.wikipedia.org/wiki/Inrush_current_limiter

The way it works is that is starts out at a high resistance when cold and that limits the current that can inrush into the caps behind it.  Then as the current starts to flow, it heats up and the resistance lowers to some nominal value.  When it's hot, it's essentially a dead short (short term repair hint).  Where they are really important is when you have a lot of equipment that would all turn on at the same time and combined might trip a breaker or something.  Another thing to watch out for is that you need to give it enough time to cool off when the equipment is off to let it return to the high resistance state to be effective.  Fast cycling makes these useless.

They typically have 4 main parameters.
1) Cold resistance - Must be high enough to limit the current to acceptable levels.
2) Hot resistance - Must be low enough to not get in the way of the circuit or overheat.
3) Max Current
4) Max voltage

Match those up as best you can with how you think the circuit is working and you should be good. 

[rob77]

yes it's just a NTC - take one from anything else all SMPS have those at input (PC power-supplies...etc).

[Smokey]

yes it's just a NTC - take one from anything else all SMPS have those at input (PC power-supplies...etc).

Just make sure you don't take one from something lower current or lower voltage...
The KC003L-ND noted was 8A continuous...