Usefulness of an ESR meter when diagnosing monitor issues?

[Sarver Systems]

How useful are these for diagnosing typical monitor issues?

The one I am getting can test the parts in circuit, auto-scales, and has the ability to read transistors, diodes, and resistors.

[twistedsymphony]

When it costs about $7 and a half hour of time to just replace all the caps on a chassis and not have to worry about it... why bother even testing them?

[Sarver Systems]

Not all monitors take just 1/2 hour though.

I always replace every cap anyways, but I think it would be nice to say "here's your problem right here!" and point it out.

Plus, I'm thinking it can be used for other components on the boards as well, I'm just not sure what I'd be testing.

[Ken Layton]

My dedicated ESR Meter (the CapAnalyzer 88A) is used every day on monitors and power supplies. I don't trust those "multi-function" ones that you describe as testing transistors and diodes. I like dedicated ESR meters myself, but it's up to you.

If I'm working on a Wells Gardner 4600, 4900, or K7000, for example, and it's never had a capkit, I don't even bother testing caps. I just go right ahead and recap it automatically.

Now if I'm working on an oddball monitor or a fairly new one, then I will use the ESR meter.

[Sarver Systems]

Do you have pretty good results with testing the caps in circuit?

ANd I see it warns to always discharge them before working on the caps. Would you suggest just discharging the entire chassis (as normal) or going through and shorting out each cap before I test it?

[MonMotha]

It's not possible to categorically say "you can test a capacitor in circuit".  There are sometimes things you can do to back out the behavior of the surrounding circuit but often not, and being able to dynamically figure all that out with minimal or no operator intervention...good luck.  Figure you're always going to have to isolate the component to test it, regardless of your test methodology.

As to the usefulness of a good capacitor analyzer, they're super useful.  Like Ken, I have my doubts about the cheap multi-function handheld things sold for pennies.

[ed12]

no
go with a good esr meter olny
same with a lcr meter
they are built for a specific job..pay the money once and never look back..
but as has been said here a 1000 or more time's,older electronic equipement will need
cap's..do NOT SECOND QUESS IT..to prove your point just replace all of them
then when the person asks why point out the few bad one's,and say the rest were to go anytime..walk away
in my shop as a rule every monitor i get in >but like ken states age<
they get cap's >complete<,even switch mode supply's and i will add mother-board's
for the price of a cap and the piece of mind i get
it is worth it...

ed

[lilshawn]

it is useful... but only if you know what to look for and know what you are doing.

i too also have the 88A, and while it does a good job at what it does, you also need to know things about the circuit in order to properly interpret the results.

for instance you could have a bad cap read good on a circuit if there is another cap in parallel with it.

the tester is basically a low ohm reading meter. a tiny difference in resistance is an indication it's going/gone bad. the problem with electricity is it's lazy. it will go through the path of least resistance... guess what, that paralleled cap, or diode or other component is an easier place the flow through than this old tired cap. So it reads good. a cap analyzer is not a "catch all" for cap problems.

for what it costs, recapping an entire boards capacitors is not only straight forward, but economical in the long run. better to recap now for 10 bucks worth of parts than replace blown IC's and MOSFETS later at 10+ times the cost. (and that's assuming you can even find some of those parts anymore.)