Cap Checker

[Sonik Wiz]

I was browsing a vintage TV restoration website the other day. Just like repairing/restoring quad gear the question of capacitor quality (esp electro's) is a hot topic. In quad gear it's considered best practice to simply replace certain caps. Or there are ways to check them out of circuit. But it seems in the world of old timey TV, much older than quad stuff, the preferred method is to check them in circuit & replace only if needed.

This is brand new to me. The product of choice is the Electronic Design Specialist capacitor checker:

https://www.ebay.com/itm/283359218491
It seems like a well designed & useful tool. A little bit 'spensive but handy for someone with a steady parade of audio/video gear on the workbench. Does anyone own, used or otherwise have any experience with this gadget?

 

[DuncanS]

One company I worked for years ago had something very similar to this in our lab (useful when we were designing PSUs and had an 'issue') ESR70 Datasheet.cdr (farnell.com) looks better than the one on eBay and about £70 ESR+ Capacitance and ESR Meter - Peak | CPC UK (farnell.com) I think you should be able to get it from Newark (which is part of Farnell) in the USA ESR70 - Peak - ESR Meter, Capacitor, Atlas ESR PLUS (newark.com) at $98

 

[gene_stl]

My local electronics and surplus store Gateway Electronics which just went out of bidness after about 60 plus years used to sell those peak testers (much of their line) and I was always tempted.

One might find some cheaper ones from China. I have a local engineer friend I can ask. One of his hobbies is finding those things. Although $98 for the peak isn't too bad. It is more than I usually wanted to spend. I probably ought to buy one since I have a lot of vintage gear.

Edit: My friends answer had nothing to add. Sorry.

 

[Sonik Wiz]

Thanks for the feedback, friends. I guess this kind of device is better known than I thought. And cool that there's a choice in similar products.

A fairly common design "audiophile" power supply is to bypass the basic large electro caps with smaller value caps in parallel. I wonder how it could detect if only one of them is bad?

I think the real value in this gizmo would be in pre-testing a unit. Check some caps & see if it's safe to turn on & start evaluating it.

 

[Doug G.]

I have always removed capacitors from circuit and tested them, regardless of the old idea to just bridge a new one across a suspected one. In electronics, it's always good to do the most dependable thing.

I have two different cap. checkers and they always test pretty closely and I have never had a cap. be bad when tested good on either device.

Doug

 

[Gimme 4]

I began using an ESR meter at work back in the mid '80s. That's what the ebay listing is. Removing an electrolytic cap and testing its capacitance can fool you. I wasted hours until the shop bought one, a Capacitor Wizard, for the techs to share. Saved many hours of frustration after that! But I had to get my own because I was working on switching mode power supply (SMPS) failures mostly in VCRs and got tired of having to hunt down the one in the shop. Bought a neat one in kit form from Dick Smith Electronics out of Australia. The black one. Used that at the shop until I retired in '07. But before that the darned things are so handy I had bought a "Blue" ESR meter kit for home use. Now I have two here. If one bites the dust I'll have a backup.

Reason you can use it in-circuit is because it does the testing with less than 1/2 a Volt AC, below the conduction of semiconductors.

If the ESR (equivalent series resistance) is good, 99.99% of the time the capacitor is good.

Using the "Blue". Left is from some VCR board don't recall, right is testing the Hi-Fi audio board out of a JVC HR-S5800 VCR. I know that one because I stil have that VCR. Fancy S-VHS model.

I would simply go through the board(s) and test all the electrolytics, and mark the bad ones with a dot with a felt tipped marker. Replace the bad ones. Fixed!

Sharp needle probes I found on ebay years ago.

Electrolytic capacitors: The bane of consumer electronics!

 

[quadsearcher]

Hoo boy! Yes. I've had that model since they were $179 in the 90s(?) A couple good things about it: The tweezer probe is shaved down on the inside so it can test ESR in surface mount caps, that's what sets it apart from others. Also, when cradling a board full of standard caps, it is a lot easier to flip back and forth when both the probe is used with one hand. After checking a couple thousand caps (maybe), I"ve had the tips break. EDS sells new ones or I've soldered a cut-down sewing pin on there. It has a sequence which can be bypassed that discharges the cap, checks DC resistance for shorts, then displays ESR.
Right, it can't tell how many caps in parallel, so if it sees a 1000uF for instance, with a 1uF across it, it will look like a good 1000uF cap. It's relatively rare to find bad filters with this, they go bad with value and can still test good ESR, but the opposite does happen especially on small filters for low current secondaries, just saw one in a Yamaha preamp. Its strength is with signal caps as they won't have other capacitance in parallel. An amazing tool when camcorders were around.
A Sony rep told me about the first one I got, a Creative Electronics model with alligator clip leads. That one is good for axial lead caps in old stuff, and the trick with alligators is to put a small brass finish nail pointed out in the clip for radials or SMT.
To do axials with The EDS unit, another jumper is needed.
Great company, I've talked to the founder, great alignment instructions, and support.

I've found many many small signal caps in FM circuits, preamps, video, [edit: and SMPS especially that pesky timing cap} etc, that would otherwise take a good service manual and scope and time to trace, where with this it is quick to test a bunch of caps and know at least if it isn't one of them, then dive deeper.

I do the same as Gimme 4 above with felt markers.

A tip on the EDS unit, I take the power switch cap off of it so it won't accidentally turn on when set on its face. It eats batteries.

 

[Gimme 4]

I see quadsearcher posted almost the same time I did. I will concur that using an ESR meter on big filter caps like 10,000 uFd in linear power supplies isn't nearly as effective or conclusive than on ones less than say maybe 2200 uFd or smaller.

Oh, and Doug G., haven't I seen you on the AK site? Your avatar looks familiar. I haven't been on there in years.

 

[MidiMagic]

What these do not test for is effective working voltage.

Often electrolytics "reform" over time, increasing their capacitance while reducing working voltage. A failure often occurs when the applied voltage exceeds the lowered working voltage. BANG! The capacitor explodes.

 

[Gimme 4]

What these do not test for is effective working voltage.

Often electrolytics "reform" over time, increasing their capacitance while reducing working voltage. A failure often occurs when the applied voltage exceeds the lowered working voltage. BANG! The capacitor explodes.

Luckily I guess, of the hundreds I've done that's never happened. I generally don't work with high voltages anyway.

If you put one in backwards polarity reversed yes you can get a BANG!

Sometimes you can tell a bad cap just by looking. I recognized this one in an ebay listing for a DTVPal DVR and bought it NOW.

 

[Imbobman]

I began using an ESR meter at work back in the mid '80s. That's what the ebay listing is. Removing an electrolytic cap and testing its capacitance can fool you. I wasted hours until the shop bought one, a Capacitor Wizard, for the techs to share. Saved many hours of frustration after that! But I had to get my own because I was working on switching mode power supply (SMPS) failures mostly in VCRs and got tired of having to hunt down the one in the shop. Bought a neat one in kit form from Dick Smith Electronics out of Australia. The black one. Used that at the shop until I retired in '07. But before that the darned things are so handy I had bought a "Blue" ESR meter kit for home use. Now I have two here. If one bites the dust I'll have a backup.

Reason you can use it in-circuit is because it does the testing with less than 1/2 a Volt AC, below the conduction of semiconductors.

If the ESR (equivalent series resistance) is good, 99.99% of the time the capacitor is good.
View attachment 79464

Using the "Blue". Left is from some VCR board don't recall, right is testing the Hi-Fi audio board out of a JVC HR-S5800 VCR. I know that one because I stil have that VCR. Fancy S-VHS model.
View attachment 79465
I would simply go through the board(s) and test all the electrolytics, and mark the bad ones with a dot with a felt tipped marker. Replace the bad ones. Fixed!

Sharp needle probes I found on ebay years ago.

Electrolytic capacitors: The bane of consumer electronics!

Hey Gimme4,
I have the same ESR meter as you do & in a kit version also. I used it in checking Electrolytic caps from my AR-9 speakers.
I've got the blue one... Also, a fun build in kit form. Very useful instrument!

 

[Gimme 4]

They're handy too, if for example you want to know the resistance of that fancy new 10 ga. fine stranded oxygen free copper speaker wire you just bought. They will measure down to .01 Ohm.

 

[Doug G.]

I see quadsearcher posted almost the same time I did. I will concur that using an ESR meter on big filter caps like 10,000 uFd in linear power supplies isn't nearly as effective or conclusive than on ones less than say maybe 2200 uFd or smaller.

Oh, and Doug G., haven't I seen you on the AK site? Your avatar looks familiar. I haven't been on there in years.

Yes, I am on AK, quite a few years.

Doug

 

[Gimme 4]

Yes, I am on AK, quite a few years.

Doug

I just found me on there. Says I was last on in Jan '21 but I don't remember that. Someone must have PM'd me and I logged in and responded. Since Nov 2008 and 4,940 posts. I know I haven't been active since Jan 2014. Different user name than here.

I hope Mark the Fixer is still there and health is OK. He was great with patience and Pioneer gear.

I have a picture taken by my father similar to your avatar of me putting together a Heathkit clock radio when I was 11.

Back to that Hendrix box set! 4th go-round!

 

[Gimme 4]

Amazing to me these are still available. Seems a long time ago when I was purchasing and assembling mine.

The "Blue" can be had fully assembled for $10 more than the kit.


Looks like "Alltronics" is a US firm, "Altronics" is in Australia.

 

[gene_stl]

Alltronics with two Ls is a surplus electronics place. When my local place finally folded after sixty years I think they bought up part of the corpse.

 

[Imbobman]

Amazing to me these are still available. Seems a long time ago when I was purchasing and assembling mine.

The "Blue" can be had fully assembled for $10 more than the kit.


Looks like "Alltronics" is a US firm, "Altronics" is in Australia.
View attachment 79527

That's mine on the left: ESR: Equivalent Series Resistance, can be a mysterious thing....[/QUOTE]

 

[Gimme 4]

That's mine on the left: ESR: Equivalent Series Resistance, can be a mysterious thing....

I think of ESR as an internal resistance that shunts the high frequency junk to ground that you're trying to filter out, or passes the high frequencies through the cap as in a coupling capacitor. The lower the ESR the better the cap does shunting that noise or passing the HF through.

I will add that many capacitors won't be under that much stress if they are just filtering 60 Hz or 120 hz ripple. What would get most of the fails I would see is the really high frequency noise passing through the capacitor to ground in a SMPS. Over time the ESR starts going up with and inside that capacitor it starts heating up and drying out the innards and can make the cap swell on the top, and eventually the heat makes it fail completely. I would see certain Samsung multistandard VCRs come in almost weekly with an electrolytic failed in the power supply circuit. Even a new cap, low ESR 105°C spec, would run warm to the touch.

 

[MidiMagic]

I have a DMM that has a capacity function.

 

[Gimme 4]

I have a DMM that has a capacity function.

Yep that's what I use on the big uFd value caps.