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LK72B ceramic disc capacitor labeled 5 NPO?

sbcrockett

sbcrockett

AK Subscriber
Subscriber
During the replacement of some really flux filled component lead sleeving, I removed a ceramic disc capacitor that said 5 on it and 10%. The Scott parts list calls it a ceramic capacitor, labeling it 5 NPO and can be seen in the schematic below (C16).

First off, I don't know what the value is because it isn't steady on my Fluke meter. This leads me to believe it may be bad. There is another one with the same markings but it's in circuit and I haven't removed it yet.

Second, could someone tell me what value I'm looking for? Also, what voltage? The Scott assembly parts list didn't specify. I haven't found anything similar on Mouser or Digikey.

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The white one is a .1 uF and has now been replaced with a matching yellow one :)
 
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A very kind Buck Rogers messaged me that 5 NPO is 5 pF and, since there's no way my meter is going to measure that small of a capacitance, should I assume it's fine and just install it? Or is there value in replacing those small disc capacitors?
 
sbcrockett said:
A very kind Buck Rogers messaged me that 5 NPO is 5 pF and, since there's no way my meter is going to measure that small of a capacitance, should I assume it's fine and just install it? Or is there value in replacing those small disc capacitors?
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NPO ceracaps are usually ok.
 
As mentioned above, any ceramic or brown epoxy capacitors are very stable. They should be as good as new and I would recommend not "messing" with them. As for the American Radionic Ceracaps, the late manufacture ones may be OK, being either Mylar or Di Film. "Di Film was a dual layer polyester and paper dielectric which supposedly "offered the advantages of both dielectrics." (Direct quote from a member of ARF). Sometimes they will test "Excellent". But I still always replace them.

On the bench right now are two Motorola 6V6-PP amplifiers that I am restoring. It has a mix of American Radionics and Good-All capacitors. Every Good-All capacitor is leaky. But the American Radionic .01µFD capacitors all were very leaky. But the .05µFD caps all tested good. By the way, they are already in the trash can... all of them.
 
5 picofarads. The NP0 means Negative Positive 0, or no temperature coefficient. Fancy words meaning it doesn't change value with temperature. Usually thats more important in a tuner circuit.
 
gadget73 said:
5 picofarads. The NP0 means Negative Positive 0, or no temperature coefficient. Fancy words meaning it doesn't change value with temperature. Usually thats more important in a tuner circuit.
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Supposed to be good for audio apps as well.
 
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