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Old 12-03-2017, 12:24 AM   #41
momaka
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Default Re: Sony Wireless Headphones MDR-RF820

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While playing with the multimeter, I checked the removed caps from the PCB board, the Lelons and Sam Youngs... And according to the multimeter, their capacitance was almost identical to the rated values. So maybe nothing was wrong with them to begin with and I replaced those for nothing.
Well, it's wasn't for nothing. Without having the proper test equipment, there was simply no way to know if they were the problem or not.

On that note, just because your multimeter shows they have good capacitance doesn't mean their ESR is good. And when the ESR is too high, the cap is as good as dead. So keep that in mind when testing caps, as I have a glass full of small caps that read "good" capacitance but terrible ESR. Most of them were startup caps that came from "dead" power supplies . Needless to say, these caps were the problem for with those power supplies. So don't rely on the capacitance reading alone.

That said, your caps were probably good. But gain, there was just no way to know without eliminating them first.

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I haven't been in for a while, a bunch of stuff came out to be concluded.
Anyway, I recently got an AN8008 multimeter, it has the required measurement capability with auto mode. So now we can test that signal, you'll just have to direct me on what to do exactly.
I'll have to have a look again at what I wrote, as I've forgotten most of my ideas. Might take me a few days or more as I have some things to do tomorrow and next week.
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Old 12-03-2017, 04:34 AM   #42
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Default Re: Sony Wireless Headphones MDR-RF820

@momaka

Thanks. I had been quite busy these past few weeks, that is why there was such a delay since my last posts.
Yes, I've read about the ESR and, as a matter of fact, I am waiting for a MK328 ESR meter, it should arrive sometime during december and I will test the caps with it also. I did some capacitance testing on some old Nichicons 6.3V3300uF which I had removed from a dead motherboard before and saved them so I could practice and learn on them with the meters, and on some of them the capacitance was measured at over 4000uF, one was even ~5200uF, with no signs of bulging. So those are probably bad and I am looking forward to measuring their ESR to see how it goes.

Anyway, thanks for the upcoming help on your part, whenever you have some time, I will appreciate it very much.

Last edited by UserXP; 12-03-2017 at 04:39 AM..
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Old 12-09-2017, 02:25 AM   #43
momaka
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Default Re: Sony Wireless Headphones MDR-RF820

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I did some capacitance testing on some old Nichicons 6.3V3300uF which I had removed from a dead motherboard before and saved them so I could practice and learn on them with the meters, and on some of them the capacitance was measured at over 4000uF, one was even ~5200uF, with no signs of bulging. So those are probably bad and I am looking forward to measuring their ESR to see how it goes.
Let me guess - HM and/or HN series with H01xx through H04xx date codes?
Sounds about right to me . These series had problems between year 2001 through 2004 (and early 2005, too). The high capacitance you see is a result of high internal (current) leakage in the cap (i.e. a lot of charge is jumping between the positive and negative cap foil layers).

Don't be surprised if you find the ESR on some of those caps to show up as "good" - again, that's due to the high internal leakage current in the cap. But in reality, these caps have failed. DO NOT re-use any of them. If you connect these caps to a strong voltage source, they will likely bulge and vent rather violently. Already been there and done that - and it didn't smell so good.
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Old 12-09-2017, 05:44 PM   #44
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Default Re: Sony Wireless Headphones MDR-RF820

Wow, a true master of capacitors knowledge.
Yes, they are HM series, H0431. I will not use them, but I am curious as to what their ESR will be. Then they will probably be tossed away.
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