Author Topic: EEVblog #365 - ESR Meter Bad Cap Monitor Repair  (Read 46100 times)

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Offline Slobodan

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #100 on: October 07, 2012, 04:22:53 pm »
The problem is that Serbia is not "PayPal certified", and I also don't own any of the credit cards, so I have to order the components indirectly, via this firm: http://tagor.mycpanel.rs/tagor.rs/tagor/
And they only order from Farnell.
 

Offline dino

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #101 on: October 07, 2012, 05:15:24 pm »
Zdravo Slobodane  ;)

You should get a credit card, for example Visa Virtuon. Electronic stores in Serbia have a poor choice of components, you are better off ordering online.

Your best chance for getting exotic components is Sprint Elektronika from Novi Sad, they order via Farnell every 10 days or so, I got myself some micro usb connectors from Farnell this way :)

this website is well known among the guitar stompbox builders:
http://www.banzaimusic.com/Panasonic-c-1534/
they have some nice panasonic caps
 

Offline Slobodan

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #102 on: October 07, 2012, 05:25:53 pm »
Hvala. (Nece cirilicu da primi majke im ga nabijem  ;D).

Thanks.
« Last Edit: October 07, 2012, 05:27:24 pm by Slobodan »
 

Offline Pentium100

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #103 on: October 07, 2012, 07:19:05 pm »
Generally no more VGA for me if i use it for my main monitor, (well AMD bought over ATI in 2006 and starting from the 6000series no more ATI branding) because i can't drive VGA up to higher resolutions! I never knew 6850 had VGA output versions, was that the free adaptor or what? If i didn't need so much horsepower but more useful outputs i would go for 6450/6570/6670
The 6850 does not have a separate VGA port, but as a DVI-I port and a free adapter in the box. I use 1920x1200@85Hz, so VGA is good enough for me, the monitor also supports 2304x1440, but then I would have to connect it directly as the KVM switch does not have enough bandwidth. If there are any 24" LCD monitors with equal or higher resolution, they are probably really expensive (or built like crap), so even though my FW900 is old, it it still built properly (because it was expensive when new).
I like to play games, so I have a powerful card :) The GT620 is there for hardware physx.
 

Offline G7PSK

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #104 on: October 07, 2012, 09:18:53 pm »
CPC Farnell open accounts for any one in the UK,they had a big tv campaign a couple of years ago to get people to sign up. The problem I have found is to get free delivery you must order over £50-00 otherwise they charge £8-00 delivery even if you buy one resistor that could be posted for a few pence.
Some one asked about using a scope to measure esr I think that W2AEW posted something on this a while back.
 

Offline lowimpedance

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #105 on: October 08, 2012, 01:04:04 am »
 Just one additional comment about these sorts of repairs (be it monitors, tvs, or whatever), is to check for dry joints as well since more often than not there will be one lurking around those 'HOT' area's.
 I have done my share of monitor etc repairs with the bad caps and have also seen most containing dry joints too. Given what a pain in the rear in getting these items open!!.
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 

Offline SteveyG

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #106 on: October 08, 2012, 07:42:29 am »
CPC Farnell open accounts for any one in the UK,they had a big tv campaign a couple of years ago to get people to sign up. The problem I have found is to get free delivery you must order over £50-00 otherwise they charge £8-00 delivery even if you buy one resistor that could be posted for a few pence.
Some one asked about using a scope to measure esr I think that W2AEW posted something on this a while back.

I've not used CPC for many years now, but wow their delivery has gone up! I still have a catalogue somewhere that says £2.50 for orders under £25!

I did manage to blag it once and asked the lady to waive the delivery fee for ordering a single SCART connector :) Never tried it since because for personal orders used to build up an list of parts to order over a few weeks.
« Last Edit: October 08, 2012, 07:45:18 am by SteveyG »
 

Offline Wytnucls

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #107 on: October 08, 2012, 09:22:32 am »

47 mA will be RMS ? The 240mVpp over the cap is the impedance so ESR and reactance.  47 mA rms will be 94 mApp. So impedance is around 2.5 Ohm. But that is the complex impedance. But besides that you did not measure ESR this way.
You have to meaure the voltdrop over the ESR, not over the cap. It it the part that drops straight down. First the triangle rises, on a fast scope you then see a spike, the ESL, then it drops straight down, the drop over the ESR ( but corrected for the spike) and then the slope goes down under an angle over the Xc. I'm afraid you meaured ESR and Xc together and mixed up rms and Vpp.

The tables are useless for general use because those are made to compensate for the wrong results of the meters.
Use a 1KHz square, ESL is so small in that case it will not matter. Use coax, T-pieces and in line terminators, no probes, this all to avoid ringing. Measure current paek to peak  over a pure resistive dummyload you place between cap and ground. Connect it using a T piece . Use also a T above and below the cap for measuring the voltdrop differential. Voltdrop divided by current is ESR. ( or meaure current differential over a inline resistor above the cap, and measure the cap single ended.

I have a piece on my site about this methode but i made that while ago, corrected it some times when I learned more about this. So some of the math is not excact correct because Later I had not all data needed to correct for some meaurement setups, but the info is for 99 % still OK. I am going to do new meaurements and make a new page with some better compares because i now have the gear to do real excact meaurements as a compare. ( like 0.01% capacitor bridge, vector RF-IV measuement options for both my vnas ect and things like GR reference capacitors with known ESR.

i will post the link here as it is finnished
The old one is at www.pa4tim.nl and use the searche box to look for ESR. You find the page, it is in Dutch and English with a lot of pictures.
Thanks for all the info; I'll try to measure it all again when I get home. Sounds like an awfully complicated procedure to check a bunch of caps on a regular basis. I think a proper ESR meter is the way to go, if one doesn't mind spending some cash.
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Offline PA4TIM

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #108 on: October 08, 2012, 11:52:48 am »
That is a nice forward control. I had a 101FC ambulance but with pain in my heart I had to sell it a month ago because of health isues. Still have a 88 series 2a stationwagon ( and a 90 V8 as familycar)
www.pa4tim.nl my collection measurement gear and experiments Also lots of info about network analyse
www.schneiderelectronicsrepair.nl  repair of test and calibration equipment
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Offline Excavatoree

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #109 on: October 08, 2012, 12:09:59 pm »
On an earlier page, the use of incorrect capacitors was discussed.    When my company threw away about 15-20 monitors, over a few months, I took them and thought I'd try to fix them.

The first three I just whacked in any old cap that fit - I was ignorant and didn't know.  They all worked.  I sold one to a colleague for the cost of the capacitors.   I later learned that I had messed up.   I hadn't considered ripple current. or anything else other than value and size.  These were name brand, capacitors, however.

 I researched and spent some time picking out the capacitors with the highest life and highest ripple current that would fit.   I went a bit crazy, looking at it like an exercise.

I went back in to the monitors with the wrong caps and replaced the two or three that were out of spec.  (didn't meet or exceed the CapXon published spec.  despite the fact that CapXon didn't meet it either.)

I told my colleague that I needed to fix his monitor.  He said he couldn't be bothered to bring it back to me, he'd just run it until it dies.  It's been going for a year now.   I'm interested to see if it lasts as long as it did with the "CrapXon" capacitors.
 

Offline Slobodan

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #110 on: October 09, 2012, 04:10:13 pm »
The capacitors I have ordered have just arrived, and 3300uF 25V Panasonic ones look like they are "No name", they dont look like Panasonic at all (they are just black-white, not black-gold, and there is no manufacturer name).
I have also got some 1000uF 16V and they are Panasonic, and also 1000uF 25V wich are Rubycon.
But on these ones it only says:

3300uF
25V
105oC FR
1025MC

So, did Farnell screwed me?

http://uk.farnell.com/panasonic/eeufr1e332/capacitor-radial-25v-3300uf/dp/1800661
« Last Edit: October 09, 2012, 04:12:48 pm by Slobodan »
 

Offline PA4TIM

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #111 on: October 09, 2012, 05:14:24 pm »
I am testing several caps on esr on several ways, just finished the squarewave and ESR meter measurements. Measured at 120Hz, 1, 10 and 100KHz. But for the > 1000 uF caps 100KHz gwas useless, their SRF was under 100KHz so they are inductive.

Then I looked up the manul of my peak atlas ESR60. It should measure using 100KHz. But it is very strange, spend an hour measuring with a scope to see the signal. After many one shot, deep memory ect trials every measurement shows just one single pulse. If someone has that peak too, can you hook it up to a scope ?

about the Farnell caps:

One of the caps was a 3300 uF 63V, it was from Farnell but I could not remember what partnumber or brand i ordered that time, It had a M in a square on it, and that is matsushita - panasonic. Its black with grey. But there is no panasonic printed on it, but all other markings are correct for that type. Looked at the bill and indeed I ordered panasonic.

The datasheet from Farnell on your link shows the code ect. Have you looked there ? I think it is original because you ordered a FR series and that is printed on your cap.
www.pa4tim.nl my collection measurement gear and experiments Also lots of info about network analyse
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Offline Slobodan

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #112 on: October 09, 2012, 05:37:19 pm »
The other Panasonic cap has "M in a square" symbol but this one doesn't have anything.
I didn't understand what you meant about the codes in the datasheet, it says that the part number is EEUFR1E332( ) but I don't know what 1025MC means.
 

Offline mariush

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #113 on: October 09, 2012, 05:40:37 pm »
They are proper Panasonic FR, the FR series is updated FM series but with white text on black pvc.

You can tell they're Panasonic by the M in the square with rounded corners, the T  with bent top line and usually they also have a product code with red paint on them, and the distinctive shape of the bottom.
The FR misses some of those depending on the can size. 

PS. The white tape is just my own way of keeping the capacitors organized. I'm a bit anal about it.
« Last Edit: October 09, 2012, 05:44:03 pm by mariush »
 

Offline Slobodan

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #114 on: October 09, 2012, 05:51:38 pm »
OK then. Thanks.
 

Offline dmather

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #115 on: October 10, 2012, 06:43:37 am »
Hey I was just wondering, could an LCR meter be used instead of an ESR meter?
 

Offline tom66

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #116 on: October 10, 2012, 07:36:43 am »
If it can measure an R plus  C component - some cannot.

One BK meter using the all-in-one chip for LCR meters sold it as an upgrade for $100! The chip is perfectly capable of doing it, probably just a feature enabled in the main micro eeprom.
 

Offline T4P

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #117 on: October 10, 2012, 08:34:54 am »
The BK 878A is just a Tonghui LCR meter isn't it?
 

Offline robrenz

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #118 on: October 10, 2012, 11:03:16 am »
(I initially placed this in the wrong thread and then moved it here. My apologies if you saw it elsewhere)

This thread made me get out my DE-5000 LCR meter and try it on ESR measurements. I was initially disappointed at the low ESR resolution on large value caps but then I wondered if the series resistance mode gives the same readings as ESR in capacitance mode.

To access ESR, D, Q , and theta you have to be in manual series capacitance mode (not auto LCR mode) then you can cycle through each on the secondary display. I can measure a 1000uF cap at 100Hz thru 1kHz but at 10kHz and 100kHz it gives overload which it should. In auto LCR mode it actually shows the inductance of the cap at 100kHz.

The max ESR resolution at 1kHz is 0.01 Ohm and this 1000uF cap reads 0.04 Ohm.  If I switch to reading series resistance it reads .047 Ohm (1mOhm resolution) still at 1kHz. Now in series resistance mode I can switch the frequency to 10kHz and it reads 0.045 Ohm and switch to 100kHz and it reads 0.032 Ohm.

Now a 6000uF cap (reads 7450uF) at 120Hz gives an ESR of 0.0  and I cant go to 1kHz because it will show overload. Switch to series resistance mode and I get 0.075 Ohm at 1kHz, 0.068 Ohm at 10kHz, and 0.065 Ohm at 100kHz.

So it seems the series resistance mode is an effective high resolution ESR reading and allows all frequencies to be used. I could be misguided here so please comment if this is bogus. If this is valid it would think it would apply to all meters using the chipset of the DE-5000.  Anyone with one of the Agilent U1733C LCR's could see if this applies to them also. It has 0.1mOhm resolution in some ranges.

I compared the  DE-5000 to my calibrated LOM-510A on a nominally 50mOhm resistor.  LOM-510A reads 58.76mOhm (max error +/- 35uOhm) and the DE-5000 in series resistance mode at 1kHz reads a very slow bobble between 58-59mOhm and it is on 59 most of the time. I always promote LCR's on the forum for inexpensive accurate low ohms and this is why.


« Last Edit: October 10, 2012, 12:32:30 pm by robrenz »
 

Offline tom66

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #119 on: October 10, 2012, 12:54:34 pm »
The BK 878A is just a Tonghui LCR meter isn't it?

Probably. You can get equivalent performance without the BK logo for half the cost.
 

Offline Psi

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #120 on: November 18, 2012, 08:52:52 am »
Just repaired a Philips LCD today (model 200W) and, for the first time ever, it was the 120uF 400V mains capacitor that was bad.
There was no external sign of failure at all, casing was totally normal.
It was a crap brand though (Capxon)

LCR said 20pF hehe.

So the high voltage main caps do sometimes die.

I could see on the scope that the poor thing was trying to start, but with 20pf of mains filtering it wasn't having much luck :P
« Last Edit: November 18, 2012, 08:56:54 am by Psi »
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Offline Rick

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #121 on: November 19, 2012, 08:13:52 pm »
Just repaired a Philips LCD today (model 200W) and, for the first time ever, it was the 120uF 400V mains capacitor that was bad.
There was no external sign of failure at all, casing was totally normal.
It was a crap brand though (Capxon)

LCR said 20pF hehe.

So the high voltage main caps do sometimes die.

I could see on the scope that the poor thing was trying to start, but with 20pf of mains filtering it wasn't having much luck :P

Same problem here with the main capacitor (100 uF 450V, "HERMEI" brand, which look normal) of a Phillips 170s 17" monitor, I think. However it is the ESR value which is equal to 0.38 Ohm. The capacitance was more or less normal 88 uF. If you have measured the capacitance with the Chinese M6013 capacitance meter, it effectively shows 14pF but after 5 sec (!) it displays the real value. I don't have spare parts for these but shall eventually replace them and give it a go. Some others display very slight signs of buldging but have normal capacitance and ESR values... Would you replace them?

2 monitors bought for $17 each for fun (as we don't have a dumpster to dive in here;)). One of them lasts 15 min after power on, then switches off; if you switch it off and on it comes back for a while then shuts down with the led on. The second shuts down 1 sec after power on. 
 

Offline PA4TIM

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #122 on: November 19, 2012, 08:55:07 pm »
100 uF and 380 mOhm is not bad for a 100 uF. What states the datasheet and at what frequency ?
And at what frequency does your ESR meter measures ? Or is it just a wild  " lets blame the ESR " guess ;-)
What ripple current did you measure using your scope  ?

I'm almost sure it is just DC leakage instead of bad ESR.

Today I got two bad caps, capacitance should be half of what they new are. Measured with a cheapo meter. They are replaced and that solved it. I could not believe capacitance was that low ( MPX capacitors)

I just measured them, capacitance is perfect, DF is to small to measure. Tommorow I will measure them with DC bias and test leakage current. They are just used to close to their max specs and that killed them.

Fred
www.pa4tim.nl my collection measurement gear and experiments Also lots of info about network analyse
www.schneiderelectronicsrepair.nl  repair of test and calibration equipment
https://www.youtube.com/user/pa4tim my youtube channel
 

Offline Rick

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #123 on: November 20, 2012, 02:46:18 am »
100 uF and 380 mOhm is not bad for a 100 uF. What states the datasheet and at what frequency ?
And at what frequency does your ESR meter measures ? Or is it just a wild  " lets blame the ESR " guess ;-)
What ripple current did you measure using your scope  ?

I'm almost sure it is just DC leakage instead of bad ESR.

Today I got two bad caps, capacitance should be half of what they new are. Measured with a cheapo meter. They are replaced and that solved it. I could not believe capacitance was that low ( MPX capacitors)

I just measured them, capacitance is perfect, DF is to small to measure. Tommorow I will measure them with DC bias and test leakage current. They are just used to close to their max specs and that killed them.

Fred

Good guess Fred.
I was working blindly. I have no scope yet.
The datasheet does not mention the ESR value, however my ESR-meter measures the ESR value at 100 kHz. The table on the ESR-meter indicates the maximum value for the ESR is 0.8 Ohm for 100 uF 250 V which is above the value (0.38) I measured. I measured the rms ripple with a multimeter (the much venerated UNI-T UT61E couldn't because the AC is superimposed on the 315V, it started beeping and the display went haywire) it varies between 65 and 300 mV but it is generally around 70-80 mV.
By the way is it safe to use a scope to visualize the voltage on the main capacitor in AC coupling, as the DC reaches 315V (connecting the ground of the scope to the minus terminal of the cap...)? This thing is directly connected to the mains (I guess I need to review switch mode power supplies before doing anything else:) ).

You meant DC leakage through one of the capacitors or the main one? Anyway thanks a lot for your input.

The main cap is an "HT" series.
« Last Edit: November 20, 2012, 02:55:44 am by Rick »
 

Offline Psi

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Re: EEVblog #365 - ESR Meter Bad Cap Monitor Repair
« Reply #124 on: November 20, 2012, 07:25:31 am »
Some others display very slight signs of buldging but have normal capacitance and ESR values... Would you replace them?

I normally replace all caps which are showing any sign of buldging.
Sometimes i replace all caps of the same brand as the ones that died.
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