In circut esr meter ????

robgest

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OK, I keep reading that you must take out capacitors before checking and then I read something else.....Who can tell me the truth about this? If I can't test them in line, why would I waist money on a meter?
 
As to "why would I waste money on a meter", a DMM does a lot more things than test caps (if it has the capacity to do that)...
 
I know that I have a lot to learn from you folks as well as reading to do. Thats why I like to get input from everyone here, and I thank you all. As far as the "waist money" thing.... I was just saying if I had to take caps out to check them, I might as well just replace them. I don't think you should ever take a chance on a bunch of parts that only cost a few bucks.
Thanks
 
Yes, most of the time a capacitor "ESR" meter will test them 'in-circuit' without the need to unsolder the capacitor under test. These kinds of meters certainly speed up testing. I use mine almost every day.
 
The good ESR meters like the CapAnalyzer88A discharge the electrolytics before testing to prevent damage to the meter from a charged capacitor.
 
I've tested caps with my DMM and an ESR only to find the cap to be bad regardless....but that is a very small amount to pass both testers and still fail.
 
The good ESR meters like the CapAnalyzer88A discharge the electrolytics before testing to prevent damage to the meter from a charged capacitor.

Ken I have seen you recommend this ESR several times, But what is the price? There web site is confusing:

http://www.eds-inc.com/cap.html

Never mind I figured out that I have to go pretty far in the process to see that it is $229.

Now what is "EDS-82B LeakSeeker HD: Shorted/Leaky component locator"? How is it different?
 
eds82b.jpg

The LeakSeeker 82B locates the exact spot on the pc board (to within a quarter of an inch) where a shorted or leaky component is bringing a power supply bus or data line to ground. It is the only locator that can locate defects from zero to 150 ohms with no loss of resolution. It can even find active shorts that a DVM won't even show. Now shipping the LeakSeeker HD , which has a High Definition mode that can locate shorted components on multi-layer boards with ground planes and a power layer. Amazing! 60-day satisfaction or money-back guaranty.

OK this seems awesome!
 
In reality if you have a short on the board they are fairly easy to find with a voltage meter and a schematic. I have a capacitor checker, but used it only a couple of times in the last 20 years that I have been working in the electronics field (and that was when it was first bought just to try it out).

General rule when it comes to electrolyic caps is if the top of the 'can' is deformed (not flat - sometimes the top is good but the bottom is pushed out, a bit tougher to see) or the plastic wrap looks like it has shrunk in size or is discolored, it is time to replace. Also a good idea to replace any of the small value capacitors just as PM (1 and 10 μF especially).

Ceramics caps are usually never an issue, resistors are obvious when they go as are diodes and transistors. Small signal transistors are usually ok, it is the driving ones (high voltage drivers, etc) that are the ones that usually cause the issues found in power supplies, high voltage and verticle deflection circuits on tv/monitors.

IMHO the only tools you really need is a good multimeter and a scope (and not so much even for the scope) - but that is just me. ;)

Electrolyic caps and driver transistors are usually the main culprits as I found in my experience.
 
I've tested caps with my DMM and an ESR only to find the cap to be bad regardless....but that is a very small amount to pass both testers and still fail.

In my experience, these are the ones that are failing under load.

However, I've had many, many situations where I've distrusted the ESR meter, and did a cap kit or whatever only to realize the ESR meter was right, the caps weren't the problem. Now I've trained myself to believe the ESR meter, as it has proven itself to be right MANY times over.
 
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