Need help with ESR(?) meter

R

root

Guest
When I have encountered power supply problems in the past
I have just replaced all the caps. I have wanted to get
an in-circuit ESR meter but they either came as kits or
were more than I wanted to pay. A while ago someone posted
here that one could get a functional ESR meter from China
for under $30. I hastily did a web search and found this:
http://www.dx.com/p/lcr-t4-meter-tester-for-capacitance-esr-inductance-resistor-npn-pnp-mosfet-m328-yellow-multicolor-364576

I ordered one and after several weeks it came today.
I hadn't paid attention to the picture. The device came
without any instructions. There is an EZ-insertion socket
which as far as I can tell utilizes only three pins, say
1,2,3. The unit works fine for testing resistors connected
either from 1-3 or 2-3 or 1-2. I wanted to test some
capacitors in circuit so I cut a clip lead in half and
connected the wire ends to pins 1-3. The device seems
to read electrolytic capacitors as diodes but gives
two uF readings which bear no relationship to the values
written on the capacitors. For example, an 800uF cap
might read 1.3v, 2.1uF.

I am hoping that someone in this group can shed some
light on the device, specifically how it can be used
to tell me which caps have to be replaced in some
device.

Thanks.
 
"root" <NoEMail@home.org> wrote in message
news:mr7khr$ptt$1@news.albasani.net...
When I have encountered power supply problems in the past
I have just replaced all the caps. I have wanted to get
an in-circuit ESR meter but they either came as kits or
were more than I wanted to pay. A while ago someone posted
here that one could get a functional ESR meter from China
for under $30. I hastily did a web search and found this:
http://www.dx.com/p/lcr-t4-meter-tester-for-capacitance-esr-inductance-resistor-npn-pnp-mosfet-m328-yellow-multicolor-364576

I ordered one and after several weeks it came today.
I hadn't paid attention to the picture. The device came
without any instructions. There is an EZ-insertion socket
which as far as I can tell utilizes only three pins, say
1,2,3. The unit works fine for testing resistors connected
either from 1-3 or 2-3 or 1-2. I wanted to test some
capacitors in circuit so I cut a clip lead in half and
connected the wire ends to pins 1-3. The device seems
to read electrolytic capacitors as diodes but gives
two uF readings which bear no relationship to the values
written on the capacitors. For example, an 800uF cap
might read 1.3v, 2.1uF.

I am hoping that someone in this group can shed some
light on the device, specifically how it can be used
to tell me which caps have to be replaced in some
device.

Thanks.
Click to expand...

They probably will not test devices very well while in the circuit. Not too
many testers will do it either for all components.

There is not too much to the testers. Just hook a component to any of the 3
leads and press the button. Some times it may help to switch the leads
around. This is especially true with some transistors that have lots of
leakage..

You can start here with a youtube video.
https://www.youtube.com/watch?v=b3dPBnYixs4
 
On 08/21/2015 10:06 AM, Ralph Mowery wrote:
"root" <NoEMail@home.org> wrote in message
news:mr7khr$ptt$1@news.albasani.net...
When I have encountered power supply problems in the past
I have just replaced all the caps. I have wanted to get
an in-circuit ESR meter but they either came as kits or
were more than I wanted to pay. A while ago someone posted
here that one could get a functional ESR meter from China
for under $30. I hastily did a web search and found this:
http://www.dx.com/p/lcr-t4-meter-tester-for-capacitance-esr-inductance-resistor-npn-pnp-mosfet-m328-yellow-multicolor-364576

I ordered one and after several weeks it came today.
I hadn't paid attention to the picture. The device came
without any instructions. There is an EZ-insertion socket
which as far as I can tell utilizes only three pins, say
1,2,3. The unit works fine for testing resistors connected
either from 1-3 or 2-3 or 1-2. I wanted to test some
capacitors in circuit so I cut a clip lead in half and
connected the wire ends to pins 1-3. The device seems
to read electrolytic capacitors as diodes but gives
two uF readings which bear no relationship to the values
written on the capacitors. For example, an 800uF cap
might read 1.3v, 2.1uF.

I am hoping that someone in this group can shed some
light on the device, specifically how it can be used
to tell me which caps have to be replaced in some
device.

Thanks.

They probably will not test devices very well while in the circuit. Not too
many testers will do it either for all components.

There is not too much to the testers. Just hook a component to any of the 3
leads and press the button. Some times it may help to switch the leads
around. This is especially true with some transistors that have lots of
leakage..

You can start here with a youtube video.
https://www.youtube.com/watch?v=b3dPBnYixs4
Click to expand...

The Bob Parker ESR meter kit will test Electrolytic caps in circuit.
We've been selling them since about 1999 and the kit has gone through a
few updates since then. Not as inexpensive as the Chinese ones, but far
better support and replacement parts are readily available...includes
schematics!

I won't put the link to my web site catalog, but my email address is the
same as the web site...

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
 
root wrote:
When I have encountered power supply problems in the past
I have just replaced all the caps. I have wanted to get
an in-circuit ESR meter but they either came as kits or
were more than I wanted to pay. A while ago someone posted
here that one could get a functional ESR meter from China
for under $30. I hastily did a web search and found this:
http://www.dx.com/p/lcr-t4-meter-tester-for-capacitance-esr-inductance-resistor-npn-pnp-mosfet-m328-yellow-multicolor-364576

I ordered one and after several weeks it came today.
I hadn't paid attention to the picture. The device came
without any instructions. There is an EZ-insertion socket
which as far as I can tell utilizes only three pins, say
1,2,3. The unit works fine for testing resistors connected
either from 1-3 or 2-3 or 1-2. I wanted to test some
capacitors in circuit so I cut a clip lead in half and
connected the wire ends to pins 1-3. The device seems
to read electrolytic capacitors as diodes but gives
two uF readings which bear no relationship to the values
written on the capacitors. For example, an 800uF cap
might read 1.3v, 2.1uF.

I am hoping that someone in this group can shed some
light on the device, specifically how it can be used
to tell me which caps have to be replaced in some
device.
Click to expand...

** You need to test some known good electros from your parts stock to get a feel for how the meter is working. Do not expect to test capacitance with the cap still in circuit.

Using an ESR meter is much like using a DC voltmeter, the reading gives useful no information unless YOU know what it SHOULD be.

Comparison with a known good electros of the same uF and voltage rating is the best way to know what is normal. Ones that read a few times higher are suspect and any that read 10 times higher are fit only for the bin.



.... Phil
 
root wrote:
When I have encountered power supply problems in the past
I have just replaced all the caps. I have wanted to get
an in-circuit ESR meter but they either came as kits or
were more than I wanted to pay. A while ago someone posted
here that one could get a functional ESR meter from China
for under $30. I hastily did a web search and found this:
http://www.dx.com/p/lcr-t4-meter-tester-for-capacitance-esr-inductance-resistor-npn-pnp-mosfet-m328-yellow-multicolor-364576

I ordered one and after several weeks it came today.
I hadn't paid attention to the picture. The device came
without any instructions. There is an EZ-insertion socket
which as far as I can tell utilizes only three pins, say
1,2,3. The unit works fine for testing resistors connected
either from 1-3 or 2-3 or 1-2. I wanted to test some
capacitors in circuit so I cut a clip lead in half and
connected the wire ends to pins 1-3. The device seems
to read electrolytic capacitors as diodes but gives
two uF readings which bear no relationship to the values
written on the capacitors. For example, an 800uF cap
might read 1.3v, 2.1uF.

I am hoping that someone in this group can shed some
light on the device, specifically how it can be used
to tell me which caps have to be replaced in some
device.
Click to expand...

** You need to test some known good electros from your parts stock to get a feel for how the meter is working. Do not expect to test capacitance with the cap still in circuit.

Using an ESR meter is much like using a DC voltmeter, the reading gives no useful information unless YOU know what it SHOULD be.

Comparison with a known good electro of the same uF and voltage rating is the best way to know what is normal. Ones that read a few times higher are suspect and any that read 10 times higher are fit only for the bin.



.... Phil
 
root wrote:
When I have encountered power supply problems in the past
I have just replaced all the caps. I have wanted to get
an in-circuit ESR meter but they either came as kits or
were more than I wanted to pay. A while ago someone posted
here that one could get a functional ESR meter from China
for under $30. I hastily did a web search and found this:
http://www.dx.com/p/lcr-t4-meter-tester-for-capacitance-esr-inductance-resistor-npn-pnp-mosfet-m328-yellow-multicolor-364576

I ordered one and after several weeks it came today.
I hadn't paid attention to the picture. The device came
without any instructions. There is an EZ-insertion socket
which as far as I can tell utilizes only three pins, say
1,2,3. The unit works fine for testing resistors connected
either from 1-3 or 2-3 or 1-2. I wanted to test some
capacitors in circuit so I cut a clip lead in half and
connected the wire ends to pins 1-3. The device seems
to read electrolytic capacitors as diodes but gives
two uF readings which bear no relationship to the values
written on the capacitors. For example, an 800uF cap
might read 1.3v, 2.1uF.

I am hoping that someone in this group can shed some
light on the device, specifically how it can be used
to tell me which caps have to be replaced in some
device.
Click to expand...

First, was the capacitor discharged before the test.

Second, did you connect it, and then press the button to start the
tests?

I have one that is similar, and it displays the capacitance and ESR for
electrolytics. I also have the original Bob Parker, and a couple other
cheap ESR meters that all give adequate readings.
 
Paul Hovnanian P.E. wrote:
Funny things hapen to electrolytics when an injected sine wave goes negative
w.r.t. the designated polarity every half cycle. That may fool your meter
into thinking it is looking at a diode or giving you strange readings.
Click to expand...

** Not relevant to modern ESR meters that inject a low current at a high frequency ( ie 100kHz) so the voltage across the cap is far too small to cause such effects.


I use a capacitance bridge (General Radio 1611-A) that allows a D.C.
polarizing voltage to be superimposed on the injected A.C. to keep
electrolytics properly biased.
Click to expand...

** That is a vintage instrument (1950s) made to test electros that were around at the time - some of which may have changed value when a DC voltage was applied.

..... Phil




..... Phil
 
root wrote:

The device seems to read electrolytic capacitors as diodes but gives
two uF readings which bear no relationship to the values
written on the capacitors. For example, an 800uF cap
might read 1.3v, 2.1uF.
Click to expand...

Funny things hapen to electrolytics when an injected sine wave goes negative
w.r.t. the designated polarity every half cycle. That may fool your meter
into thinking it is looking at a diode or giving you strange readings.

I use a capacitance bridge (General Radio 1611-A) that allows a D.C.
polarizing voltage to be superimposed on the injected A.C. to keep
electrolytics properly biased.

--
Paul Hovnanian mailto:paul@Hovnanian.com
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Charles Darwin said you can't make an omelette without breaking a few eggs.
 
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