L/C tester recommendations

[Jim Elliott]

I'm looking for a good, inexpensive L/C tester. I would prefer an in-circuit model. I've looked at the Sencore LC 53, LC 56, and CA 55, but none claim to test in-circuit.

Anyone have any suggestions?

Jim

[Phil Allison[_3_]]

"Jim Elliott"
>
> I'm looking for a good, inexpensive L/C tester.


** More info - what sort of values, what sort of circuits ?


I would prefer an
> in-circuit model. I've looked at the Sencore LC 53, LC 56, and CA 55,
> but none claim to test in-circuit.
>
> Anyone have any suggestions?


** Yeah - get real.


..... Phil

[Jim Elliott]

Thanks for the reply, Phil. I am primarily restoring tube audio gear, so we're talking about P.S. and coupling caps.

Not sure what "get real" means. I am real, with an FCC First Class, Senior Member of the Society of Broadcast Engineers, and over 40 years earning my living designing, installing and repairing electronics. Had HP's top of the line, but even it wouldn't do in circuit.

;921758']"Jim Elliott"
>
> I'm looking for a good, inexpensive L/C tester.


** More info - what sort of values, what sort of circuits ?


I would prefer an
> in-circuit model. I've looked at the Sencore LC 53, LC 56, and CA 55,
> but none claim to test in-circuit.
>
> Anyone have any suggestions?


** Yeah - get real.


..... Phil

[Phil Allison[_3_]]

"Jim Elliott"
>
> Thanks for the reply, Phil. I am primarily restoring tube audio gear,
> so we're talking about P.S. and coupling caps.


** Electro caps are best tested with an ESR meter - the cap value in uF is
irrelevant if the ESR has gone high.

ESR meters measure caps in circuit.

You still do not say what kind of Ls you need to measure or why it must be
"in circuit".


> Not sure what "get real" means.


** Spell out what you actually need instead of alluding to some fantasy
wish.



.... Phil

[Ian Iveson]

Jim Elliott wrote:

> I'm looking for a good, inexpensive L/C tester. I would
> prefer an
> in-circuit model. I've looked at the Sencore LC 53, LC
> 56, and CA 55,
> but none claim to test in-circuit.
>
> Anyone have any suggestions?

Android app? With bluetooth crocodile clip.

Shows video tutorial on how to fix circuit under test, and
berates you loudly in Chinese for your poor soldering.

Ian

[John-Del]

On Dec 12, 1:11*pm, Jim Elliott >
wrote:

>
>
> > ;921758']"Jim Elliott"-
>
> > > I'm looking for a good, inexpensive L/C tester.-
>
> > ** *More info - *what sort of values, what sort of circuits ?
>
> > I would prefer an-
> > > in-circuit model. *I've looked at the Sencore LC 53, LC 56, and CA
> > 55,
> > > but none claim to test in-circuit.


I have a Sencore, and it does read ESR in circuit. Since it's more
accurate to read out of circuit, I'm guessing back when they made them
they weren't advertised as having in circuit capability, or maybe no
one really thought about checking them in circuit. I also have a
dedicated ESR meter, and it doesn't seem to be any more accurate than
the Sencore is in circuit, and I'd bet the Sencore is more accurate
out of cirucit. And of course no instrument can read value in
circuit. In the last couple of years, I've stopped trying to save a
minute and read ESR in circuit anymore. I remove or isolate one lead
from the cap and run it through the Sencore, which will give me ESR,
value, and the capability to run voltage through the cap for leakage
tests. Although most bad electros will show bad ESR first, I've seen
plenty of electrolytics that show normal ESR, no leakage, and be WAY
off in value, or show dramatically different ESR and value after
doing the leakage test on them.

John

[Phil Allison[_3_]]

"John-Del is a Lunatic"

I have a Sencore, and it does read ESR in circuit.


** Wrong.

Since it's more accurate to read out of circuit,
I'm guessing back when they made them
they weren't advertised as having in circuit capability, or maybe no
one really thought about checking them in circuit.


** Total Lunacy.


I also have a
dedicated ESR meter, and it doesn't seem to be any more accurate than
the Sencore is in circuit, and I'd bet the Sencore is more accurate
out of circuit.

** This **** is totally out of his head.


And of course no instrument can read value in circuit.


** This **** is totally out of his ****ing head.


In the last couple of years, I've stopped trying to save a
minute and read ESR in circuit anymore.


** Wot an utter, ****ing idiot.


Although most bad electros will show bad ESR first, I've seen
plenty of electrolytics that show normal ESR, no leakage, and be WAY
off in value, or show dramatically different ESR and value after
doing the leakage test on them.


** John is a ****ing nut case ****wit.

God puts them on earth to give the rest of us someone to laugh at.



..... Phil

[Big Bad Bob]

On 12/19/10 06:48, Phil Allison so witilly quipped:
> Although most bad electros will show bad ESR first, I've seen
> plenty of electrolytics that show normal ESR, no leakage, and be WAY
> off in value, or show dramatically different ESR and value after
> doing the leakage test on them.
>

and here I was thinking that constructing a simple AC bridge with known
value capacitors and then measuring the voltages might settle it. I've
actually done this with a 60hz power transformer into a known capacitor
(let's say 1uF) and then say it's 12.6V out, and you use an AC voltmeter
and put your cap in series with the 1uF and then measure the AC volts
across your cap. The ratio of capacitors determines the voltage.
Assuming your line voltage is correct, your cap's value can then be
calculated based on the impedence ratio. Or something like that. I've
measured caps in the ~100 pf range this way. For smaller values I'd use
a higher frequency, maybe a few khz. Trick is to have a known value
capacitor to test against. But a good AC voltmeter should get you
results of 100:1 value-wise, so 1uF could test up to 100uF. And if you
needed to ensure that the working volts were correct you could bias them
appropriately with some large value resistors and just wait for them to
charge before testing.

[John-Del]

>
> .... * Phil

Phil, you are not only clueless, you are clue resistant.

John

[Phil Allison[_3_]]

"Big Bad Bob"

** Learn ot read - **** head.

[Phil Allison[_3_]]

"John-Del is a Lunatic"

I have a Sencore, and it does read ESR in circuit.


** Wrong.

Since it's more accurate to read out of circuit,
I'm guessing back when they made them
they weren't advertised as having in circuit capability, or maybe no
one really thought about checking them in circuit.


** Total Lunacy.


I also have a
dedicated ESR meter, and it doesn't seem to be any more accurate than
the Sencore is in circuit, and I'd bet the Sencore is more accurate
out of circuit.

** This **** is totally out of his head.


And of course no instrument can read value in circuit.


** This **** is totally out of his ****ing head.


In the last couple of years, I've stopped trying to save a
minute and read ESR in circuit anymore.


** Wot an utter, ****ing idiot.


Although most bad electros will show bad ESR first, I've seen
plenty of electrolytics that show normal ESR, no leakage, and be WAY
off in value, or show dramatically different ESR and value after
doing the leakage test on them.


** John is a ****ing nut case ****wit.

God puts them on earth to give the rest of us someone to laugh at.



..... Phil

[John-Del]

So today I find 3 emails in my in-box imploring me to not respond to
Phil, and to just plonk him. Well, I don't use a real news reader,
and just lurk on newsgroups occasionally, and enjoy a good laugh as
much as the next guy, so...

I come back to read this thread, and start chuckling a bit. My wife
asks what was so funny, so I told her about the post by this guy on
the thread named Phil Allison. She says "what's his name?". I
repeated it, and she laughed. She said when I said it fast, it
sounded like *Phallus One*.

Anyway, I took a half hour out my work day today and tried the Sencore
LC75 on some balky smps boards I had kicking around, and it picked up
high esr caps in circuit. The hand held esr meter I have identified
the same caps. (While I did post that I don't really use the esr
meter in circuit anymore, I should have mentioned that I do use it on
boards that have many surface mount electrolytics, like Toshiba and
Samsung hyper modules.) I also found several caps in my scrap box
that have esr within tolerance, no leakage, but show less than half
rated value. If Phallus One would like me to mail him some, I'll get
them out next week.

John

BTW guys, I will head your requests and stop poking the bear.

[Phil Allison[_3_]]

"John-Delis an utter ASS"


> So today I find 3 emails in my in-box imploring me to not respond to
> Phil, and to just plonk him.

** How funny.

So the bull****ting fools who do NOT even read my posts are the ones who
hate them the most.


> I come back to read this thread, and start chuckling a bit. My wife
> asks what was so funny, so I told her about the post by this guy on
> the thread named Phil Allison. She says "what's his name?". I
> repeated it, and she laughed. She said when I said it fast, it
> sounded like *Phallus One*.


** How totally autistic of the cow.


> Anyway, I took a half hour out my work day today and tried the Sencore
> LC75

** Fraid that pile of **** is NOT a real ESR meter !!!

If you merely read the specs of the thing, it is clearly not capable of
giving correct readings of electro ESR.

ANY meter that IS capable of reading electro ESR correctly WILL work just
fine with the cap in circuit.


> on some balky smps boards I had kicking around, and it picked up
> high esr caps in circuit. The hand held esr meter I have identified
> the same caps.

** This mysterious "hand held esr meter " of yours = what ?????

Don't be coy - out with it.

Inquiring minds need to know what POS it is.


(While I did post that I don't really use the esr
> meter in circuit anymore,


** An utterly ASININE thing to post.


> I should have mentioned that I do use it on
> boards that have many surface mount electrolytics, like Toshiba and
> Samsung hyper modules.) I also found several caps in my scrap box
> that have esr within tolerance, no leakage, but show less than half
> rated value.

** Must have been made that way or are simply mislabelled.

The process that causes ESR to rise in an electro always PRECEDES any loss
of capacitance due to old age.



..... Phil

[Big Bad Bob]

On 12/20/10 05:20, Phil Allison so witilly quipped:
> "Big Bad Bob"
>
> ** Learn ot read - **** head.

/me has a new special friend

[Big Bad Bob]

On 12/20/10 16:33, John-Del so witilly quipped:
> So today I find 3 emails in my in-box imploring me to not respond to
> Phil, and to just plonk him. Well, I don't use a real news reader,
> and just lurk on newsgroups occasionally, and enjoy a good laugh as
> much as the next guy, so...

Meathead the dog would call him 'George'

"Feed him and hug him and call him George" - something like that

> I come back to read this thread, and start chuckling a bit. My wife
> asks what was so funny, so I told her about the post by this guy on
> the thread named Phil Allison. She says "what's his name?". I
> repeated it, and she laughed. She said when I said it fast, it
> sounded like *Phallus One*.

sounds like the name of a new rocket

> Anyway, I took a half hour out my work day today and tried the Sencore
> LC75 on some balky smps boards I had kicking around, and it picked up
> high esr caps in circuit. The hand held esr meter I have identified
> the same caps. (While I did post that I don't really use the esr
> meter in circuit anymore, I should have mentioned that I do use it on
> boards that have many surface mount electrolytics, like Toshiba and
> Samsung hyper modules.) I also found several caps in my scrap box
> that have esr within tolerance, no leakage, but show less than half
> rated value. If Phallus One would like me to mail him some, I'll get
> them out next week.

does your meter allow you to DC bias the capacitors when you test 'em?
Funny thing about electrolytics is their tendency to behave differently
depending on working voltages, especially the really old kind. But then
again you'd expect values to drop too, so I don't know how valid any of
that would be.

Anyway there are "things" out there that claim to in-circuit test
capacitors, like "smart tweezers" and whatnot. They're pricey.

[Patrick Turner]

snip a bit,


> Anyway there are "things" out there that claim to in-circuit test
> capacitors, like "smart tweezers" and whatnot. *They're pricey.

Presumably such things put out a test signal and the response current
is interpreted by the gadget and it gives you an ESR figure. Measuring
in circuit when switched on implies the cap is probably biased with
correct Vdc.
It may be that the attached circuit to any given electrolytic cap may
permit in-circuit measurements but I would not rely on that to always
be the case and if I thought the cap wasn't acting quite as it should
I would prefer to remove the cap to measure it, and with correct Vdc,
on a bench as Phil suggests.

Most electrolytic caps which measure badly for C have been traumatised
by having to deal with excessive Iac currents. I've seen many cases of
typical 2,200 uF caps used to couple speakers to single rail SS amps
where the cap C has gone low or to a short after the amp has spent
time with a shorted speaker cable someplace. Failing output tubes can
also make HT caps fail from too much ripple current. But remarkably
many old caps in old radios 60 years old survive their owners
reluctance to have their radios serviced until output tubes bow out to
a short and the 6V6 fuses the OPT primary.

Of course sometimes makers get things wrong, like labelling 47uF caps
as 100uF. I have seen this very thing in expensive AR9 speakers where
a couple of the crossover bipolar el-caps were labelled with the wrong
value.

Patrick Turner.