I have a 250uF 25V cap w/ an ESR of 0.58 at 100kHz, from a mains rectifier. I'm just building up some experience with my LCR meter, so IDK, in some charts that's over. I guess if it's borderline I should replace it anyways.

 

Is there a problem with the circuit, or are you just replacing things because your new toy tells you to?

 

What are you doing? Preventive maintenance? Changing capacitors every 1000 hours, whether they need it or not?

Does the supply work? If so, leave it alone.

 

Why are you using 100 kHz. for the frequency in relation to a mains rectifier? Shouldn't you use the mains frequency? At the mains frequency the capacitor has an impedance of about 10.6 Ω, which makes the ESR about 5% of the magnitude of the impedance.

 

I have a 250uF 25V cap w/ an ESR of 0.58 at 100kHz, from a mains rectifier.

What does parameter D show? Did you check the capacitor for leakage?

 

No I put it back in for now, it does look a bit puffed on the top, but it might have looked like it new. It's out of 1 of my DMM's I'm tuning up/modding. I didn't think to check their DC capacitance either. Soon I'll have it on the scope.

I should make a leakage current tester at low voltage,

 

I should make a leakage current tester at low voltage,

Try this capacitor leakage current tester circuit.

 

Work on some well defined projects. Don't try to fix stuff that is not broke.

Let's say you were a new hire on a job. Would you like your employer to do heart, brain, liver, prostate, colon, bone marrow, and kidney biopsies just to be sure you wouldn't get sick?

 

I looked at the capacitor datasheet 250uF / 25v.ESR at a frequency of 120Hz-1Ohm.What is your ESR value at a frequency of 120Hz?
https://www.tedss.com/DataSheets/2020/2020022219.pdf

 

Well I'l have to pull it again, but I just noticed the 10V rail, only reads 6.18V w/265mVpp 120Hz ripple. that's sitting on a 10uF cap, the highest ESR of the 10uF's was like 3-4ohm, the other 2 were like 2ohms iirc.

In fact I should NOT put this back together, until I check the test-points listed in the SM.

So I had put a buzzer circuit on the 5V rail, that was too low, then I assumed the 10V rail would be a ridgid 10V, but it's crap too, and can't power a 5V regulator, so now I'll have to pull that, and just use 6.2V and screw it if my LEDs burnout faster.