Using Peak ESR60 Meter

[Andyd1970]

Hi Guys,

Have a friends set JMB set that takes ages to start up, I removed PSU and obvious bulging caps, so thought I would try my new ESR meter with the caps in circuit

Most are OK but a few I "in-circuit/leaky" so removed them and tested out of circuit and they are OK, so can someone help explain this? or shall i just replace any that say "in circuit/leaky" when tested on the PCB? One for example is a 200uf 16v, in circuit I get the "in circuit/leaky" ESR reading of 0.30ohms. out of circuit it is 223.4uf and ESR 0.28ohms.

Help

[tom66]

Re: Using Peak ESR60 Meter

Well, there's no specific rule, but I would say 0.28 ohm is bad for a 220uF capacitor.

My general rules are something like this:

<10uF 1 ohm ~ 10 ohm
10uF~100uF 0.1 ohm ~ 1 ohm
100uF~470uF 0.05 ohm ~ 0.1 ohm
>470uF <0.05 ohm

Capacitors can only be reliably tested out of circuit, despite what manufacturers claim.