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 Post subject: Which capacitor analyzer do you use, and why?
PostPosted: Apr Mon 28, 2008 2:21 pm 
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Joined: Mar Tue 18, 2008 12:15 pm
Posts: 103
I am just getting into these old classics, because I want to be able to really know what a cap is capable of (or not!).
I have a Heathkit IT-11 and a Sprague TO-6 cap analyzer.
The Sprague is in the middle of repair and calibration and I'm eager to get it done so I can compare the two.
What do you guys use for cap analysis? I went with these because they both run up to 600 volts for leakage and I think that is important. But I'm just really learning about these cool instruments. I haven't used one for 35 years and I wonder why there aren't any made today with the capabilities of these classics.
Any thoughts?


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 Post subject:
PostPosted: Apr Mon 28, 2008 3:17 pm 
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Joined: Nov Wed 07, 2007 12:44 am
Posts: 1664
Location: Hawthorne, Ca
i've been using a TO6 for years and it's a good tester, probably better than the Heathkit unit. If you're looking for extreme accuracy for cap values, I would recommend using a later model solid state tester as I've found them to be more accurate than the old tube units. The new cap testers use a nine volt battery for power because almost all of the new electronic devices being produced are solid state so there wouldn't be a market for a tester that supplies high voltage. There are very few of us that still use tubes. Harry


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 Post subject:
PostPosted: Apr Mon 28, 2008 9:54 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 218
Location: los angeles, california, usa
The Sencore LC103 uses up to 1000vdc for analyzing leakage in capacitors. However they are not inexpensive.

http://www.sencore.com/products/lc103.htm

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 Post subject:
PostPosted: Apr Tue 29, 2008 12:34 am 
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Posts: 2719
Location: Athens, Greece
HP 4261A digital RLC bridge. Doesn't do HV well but does a nice job of measuring ESR and very accurate R-L-C readings.


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 Post subject:
PostPosted: Apr Tue 29, 2008 12:39 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 26750
Location: Pocasset, Cape Cod, MA
A 4260A bridge for measurement, and my own homebrew leakage tester for the high voltage, because I want to know the exact leakage in microamps on an analog meter. My tester goes to 750V or so.


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 Post subject:
PostPosted: Apr Tue 29, 2008 2:16 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 5417
Location: Upstate NY, USA
I use a TO5. Had a TO6 but the TO5 has a more vintage look.

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Steve Johnson
http://www.StevenJohnson.com Supreme Instruments 1926-1956


Last edited by Steve Johnson on May Thu 01, 2008 4:08 am, edited 2 times in total.

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 Post subject:
PostPosted: Apr Tue 29, 2008 3:16 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 3339
Location: Medford,Or USA
I just sold my military ZM-3 cap tester to a friend. They do a good job with electrolytics, but one like Alan's that reads leakage in MICROamps is best for the new smaller value caps.
Wonder if I'm gonna miss the old ZM-3??

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 Post subject:
PostPosted: Apr Tue 29, 2008 7:31 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 12227
Location: Albuquerque, NM 87123
My ESR meter is an 88A made by Electronic Design Specialists; very nice, but really made for modern electronics. Checks surface mount caps very quickly without removing them. Good for .47uf to 2000uf.
I have 3 capacitance meters by Tenma and one by ECD; all very accurate but they don't check leakage. For that I just use a 0-400 volt variable power supply with a 100ua meter. If I think leakage is a little too high, I just compare it with a known good cap. Also good for the rare occasions when I want to try reforming a cap (usually if it's less than 20 years old).


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 Post subject:
PostPosted: Apr Tue 29, 2008 7:42 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 15736
Location: ID 83301
None .. old capacitors are usually always bad so i skip that step .


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 Post subject:
PostPosted: Apr Tue 29, 2008 1:51 pm 
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Joined: Oct Sun 15, 2006 12:57 pm
Posts: 3683
Like Ken, I don't use one either.

Initially I use a hv power supply with a current meter and apply the voltage to the UUT with the power off, and slowly dial it up. If the current is less than a few mils for the whole radio I leave it for a couple minutes and if all is stable, I just fire it up.

This is a judgement call of course. There are power supply bleeders and other voltage dividers so often you have to refer to the schematic, but bye and lardge I consider it to be either go or no go. If there are problems within a particular stage, I just measure the in circuit voltages, on either side of a suspect cap, and proceed accordingly.


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 Post subject:
PostPosted: Apr Wed 30, 2008 12:58 am 
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Posts: 2815
Location: Fort Washington,MD 20744
I use a Simpson 383-A when I am curious on a cap. It lets me check leakage on a megohm scale at 250V and lets me hit the suspect cap with a pulse of up to 900V. I can also test resistance up to 1 gig ohm and insulation breakdown voltage with it. It will measure in circuit coupling capacitors too. When I am finished testing the old caps, I replace them all just so I don't have to do it again in 2 or 3 years. Old caps I take apart for restuffing, new caps I test just because I have a tester and have a curious nature.
The ones that test marginally I sell to the audio people. Everybody is happy.

Doug


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 Post subject:
PostPosted: Apr Wed 30, 2008 1:28 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1546
Location: St. Paul, Minnesota
There's always the issue of capacitors that aren't obviously bad - if all cap. issues were black or white, there would be no need for an analyzer. You don't always face a dripping wax cap though, or a visibly-old electrolytic. Some more modern looking caps leak, and some newer-looking electrolytics have dried out. The only way to tell is to test them, and as Denis pointed out, replacement cost is not always trivial. (But I completely agree, and follow practice with, those who advocate replacing any cap. that is obviously suspect, and whose replacement cost is trivial.)


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 Post subject:
PostPosted: Apr Wed 30, 2008 1:36 am 
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Joined: May Sat 05, 2007 9:16 am
Posts: 481
Location: San Diego, CA
I use a Sprague TransFarad TCA-1 (circa 1960)--primarily for leakage tests. It measures leakage, on a meter, from 0.6 microamps to 600 microamps in 7 ranges. It also tests insulation resistance up to 20,000 megohms. A nice instrument.
Rick


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 Post subject:
PostPosted: Apr Wed 30, 2008 4:13 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 10648
Location: Valley City ND USA
Hi pre. and all, Sometimes an odd cap isn't marked. I recall one in the base of an antique fan that was leaking oil. I had to test to have some idea as to the possible needed value of replacement. Similar situations come up once in a while.

I have a tester that measures low value caps. I use it for reality check. Some of the new labeling causes me self doubt. Trust but verify as they say. :)

The testers themselves are nothing exotic. They were much appreciated gifts.

I just replace the paper ones in whatever form.....eventually. :wink:


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 Post subject:
PostPosted: May Thu 01, 2008 2:55 am 
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Joined: Oct Sat 20, 2007 3:36 am
Posts: 14393
Location: Southern NH, 03076
I see no benefit in testing an old cap for leakage, simply put in new ones or restuff and save the time now and down the road. Being able to read down to microamps may be a nice exercise to satisfy curiosity today but it means nothing next week, next month, etc when dealing with old caps.

Ive spent days reforming some caps to perfection only to have them go postal on me within a year or so of regular daily use. IMO there is no free lunch.

For general non very critical LCR measurements I use a handheld Wavetek LM22A.
For critical measurements and especially for RF I use a HP4271B digital LCR meter or a 70's military TS617C/U Q meter. The HP was around $50 at an industrial auction and the Q meter was a $44 Ebay item.

Carl


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 Post subject:
PostPosted: May Thu 01, 2008 2:59 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 3622
Location: Westminster, CO, USA
I use an eico 950b because it was cheap at a local Ham swap meet. Seems to work fine.

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 Post subject:
PostPosted: May Thu 01, 2008 3:02 am 
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Joined: May Thu 01, 2008 1:34 am
Posts: 13
Location: Birmingham, Michigan
A Sprague TO-5. A great piece.


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 Post subject:
PostPosted: May Mon 12, 2008 5:34 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 4853
Location: La Porte, IN, USA
How about ESR meters? Useful?

I have used the HV power supply with current meter, as well as an old Superior Cap tester with Eye Tube indicator, and a modern solid state capacitance/inductance meter. I zapped one of those recently by forgetting to discharge a cap I had voltage on. They do NOT like high voltage.
If I pull out a cap, I just go ahead and replace it, but it's good to know if there was leakage, as it explains many problems.


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 Post subject:
PostPosted: May Mon 12, 2008 6:21 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 21005
Location: Detroit, MI USA
I use a Sprague TO-4, because it works well and applies rated voltage for leakage tests. Found many a bad cap using it, which had checked good on other testers. Particularly good at finding intermittent problems caused by mica caps, which might show 500 megs leakage on the Sprague only when hot.

I also use a Creative Electronics ESR tester for solid state stuff. Indispensible, since those units are often loaded with tiny electrolytics which open up. I wouldn't consider servicing a piece of solid state electronics without an ESR tester. Not very useful on older vintage tube stuff, since one would usually replace all the electrolytics without even wasting time checking them.

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Dennis

Experience is what you gain when the results aren't what you were expecting.


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 Post subject:
PostPosted: May Mon 12, 2008 8:54 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1928
Location: Lakewood, California
Sprague TO-6. Because it is fast and simple. I test every new cap before installing it in a radio--once bitten-twice shy! Also like to verify what I already know about the old caps--leaky!

Based on others recommendations I guess I am going to have to break down and get an ESR meter for the few solid state auto radios I work on. Although there are not too many electrolytics in the solid state auto radios, some of them are in places that are hard to get to and remove. Especially Motorola's double-sided circuit boards.

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