Capacitor ESR readings told me something I did not expect on a 20 year old monitor

Jake Robinson · 2026-08-24T22:20:06.25568+00:00

So I finally got one of those cheap ESR meters, the $40 one off Amazon with the tweezer probes. I have been telling customers for years that if a CRT or old LCD has ripple issues, just shotgun the caps. I did that on a ViewSonic from 2004 last week, replaced all the 1000uF and 470uF caps in the power supply, but it still had a flicker. Out of curiosity I ran the old caps through the meter before tossing them. Almost all of them read within 15% of their rated ESR, even the ones that looked bulged on top. The one that was actually bad was a tiny 47uF cap in the feedback circuit, no visual signs at all. That surprised me because I always thought the big ones were the problem. Maybe I have been wasting time and money swapping out every big cap when the real fault hides in the small ones. Anyone else found that small caps fail more often than the obvious big ones in older gear?

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Capacitor ESR readings told me something I did not expect on a 20 year old monitor | Electronics Repairers - Opinions Matter