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 Post subject: ESR Meter / capacitors went very high only two years later
PostPosted: Jun Sun 25, 2006 10:29 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 129
Location: Roslyn Heights
Hi All,
I bought a ESR meter about two years ago. At that time I was changing any caps in my Neve recording console that were bad. At this time the ESR meter worked out great and was a gret help to me and I use all the time in these projects.
I wanted to keep the boards in its orginal condition as advise by Neve tecs who built these consols, the console was built in 1979.
I did get other opions to use different brands from others.
I bought the same caps that came with the console from BC Philps.
Yes I bought all new ones no NOS type.
When I first started this project I had a problem with their 16V @22uf I would test them with the meter and the by the next week the ESR went really out of spec after I soldered them into ther console.
This only happened at that time with the 22@16 volts. After soldering in around 50 capacitors.
I pulled them all out and went with a another brand that a well known audio tec advised. They are still good and so are all the 100uf @24V and 330, 440uf caps at 24 volts these are the blue ones in a small metal can type.
The 22uf ones were made of a different material, ceramic. I called Digi Key on this and I sent all the ones I pulled out and they told me that they were good even though the ESR went very hight like to 10 and 15.
That was a wast of time and money, that was two years ago.

This week I had a problem with one of eq board sectons in the console.
I decided start by checking the elecro. caps on the board that had the problem with my the ESR meter. I found that a 100uf cap at 16 volts went to 15 on the ES meter, thats way high for this cap. This is still the ones that are not blue these are made out of ceramic material. I was told by Digi Key they were made that way to be flam proof.
The orginal ones many years ago were the blue metal ones.
And as I stated all the blue ones in the can type still all test very good these are all at 24 volt.
When I replaced the bad cap I used the same 100 uf value but At 24 volts this was one of the blue ones and yes the problem was fixed.

I descided to check a few others in known working channels that used the same boards and found these same caps in the same location on the same board were way out of spec.????
The strange thing is the same cap in other locations were ok and checked out to be OK.????
Could it be that all these caps should be at 24 volts.???
Orginaly these caps were 4 and 8 volts. Today BC Philps only went down to 16 volts.
Do you have any clues as to why this happing only two years later.
And any advise? I am going to replace all the bad ones again this could be about 75 caps or more, I already changed them did twice two years ago!!!!!
And yes all the polarities are correct.
Also any tips on useing a ESR meter to double check if a cap is good or bad.
Regards,
jim

James Sabella
http://www.sabellastudios.com


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 Post subject:
PostPosted: Jun Sun 25, 2006 10:38 pm 
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Hi Jim,

When you say the caps were out of spec... whose spec? Did the caps have an ESR spec in the first place? You can't expect a device to conform to a spec it never had in the first place. OTOH, if it had a published ESR spec and doesn't meet it, there's cause for concern.

Re ESR meters... I never use them at all.

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 Post subject:
PostPosted: Jun Mon 26, 2006 12:06 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 369
We have several Neve consoles of various vintages where I work.
They always have electrolytic cap problems because of the heat that
the boards generate an the fact that they are sandwitched so close
together in the console.We can't stand those Philips electrolytic caps.
The quality of those caps is horrendous.We had the same problem that
you would put new Philips caps in and they would be bad about two years
later,sometimes even sooner if the room is warm.We stopped using the Philips caps and now use United chemicon or Panasonic electrolytic caps.We always use the 105c rated caps.The consoles are much more reliable now.The reason some of those Philips caps are still good in your Neve is because they probably are not installed near hot running parts.When you send audio signals through those caps that kills them faster too.If you are worrying about the sound changing with the different caps the mixing guys don't seem to mind.They are just happy that the boards do not crap out that much anymore.
Regards,
Swanson


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 Post subject:
PostPosted: Jun Mon 26, 2006 12:53 am 
Thanks for the replys. I did use 105 tem caps like I said the weird thing is the blue ones are fine and they in their ESR rating and I have no other problems. The ESR meter I have has a chart as to where the esr rating should be.
It was a hard decide as what brand to use I was advised by a well known tec to use the Pasonic caps but they only make them in radial.
I was also told by some neve guys in England that if I changed the brands the console would lose its value when it came to sell it.
BTW its Neve 8068 mark 2. Also like I said its only these 16 volt ones that are made of ceramic material.
I didn't know they horrendous caps if so why did Neve use them?
Also when I talked to the guys in England who rebuild these boards they told me use the same ones, who knows any more.....
Since you know what board I am talking about its the 283 C13 and the 284 board that cap number I don't remember, but can let you know.
I was told to try Lelon capacitors and I was told by P.A.S.T. in Englanrd to stay away from them from an artical he read that there was a major problem at one time with this company????. I was told by I think Digi key and otheres these are very good caps so I used them where the BC Philps caps failed that is the new BC Philps, they are still fine
Its very strange that only one cap in this one location on these two boards went very high in their ESR. and for the fact that when I changed it the unit worked fine so I know the cap went south.
Any thoughts on this or is it just bad caps.
regards
jim


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 Post subject:
PostPosted: Jun Mon 26, 2006 2:13 am 
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Anonymous wrote:
The ESR meter I have has a chart as to where the esr rating should be.

Hi Jim,

I would suggest caution when using this chart. Since your caps weren't necessarily made to that spec in the first place, you have little reason to expect them to meet it. That's particularly true if you claim that new caps don't meet the "spec".

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 Post subject:
PostPosted: Jun Mon 26, 2006 4:03 am 
I have been an electronics Teck for over 30 years and I have never used an ERS meter and none of the tecks that I know use one. What is the advantage over a regular cap checker?


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 Post subject:
PostPosted: Jun Mon 26, 2006 4:09 am 
Hi Leigh,
The new capacitors do meet the proper spec it was the ones that I was talking about that were two years old that lost their spec.
And all the others are fine except for the
100 uf at 16 volts they were the ones made from a ceramic material.
All the ones at 24volt are fine.
I'll check a few others and change any more that are way out of ERS spec just for a test and replace them with the ones that I know are good.
Regards,
jim


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 Post subject:
PostPosted: Jun Mon 26, 2006 4:10 am 
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Location: Detroit, MI USA
An ESR meter is by far the easiest way to diagnose problems with those tiny electrolytic caps on modern solid state equipment. It only takes a second to check each cap, and is done in-circuit. Every shop I have managed or worked in has used them extensively beginning many years ago when the device was introduced. It saves a lot of time, otherwise you need to scope each cap to determine whether there's a problem. It's also great for comparing the relative quality of new caps to other brands of the same temperature, value and voltage ratings when specs are unknown.

In the case of the original poster, I would recommend using a different brand of caps in this equipment to see whether or not they will last longer under the same operating conditions. My personal preference is Nichicon over any other for longevity and low ESR off the shelf.

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Experience is what you gain when the results aren't what you were expecting.


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 Post subject:
PostPosted: Jun Mon 26, 2006 6:21 am 
Thanks for the reply, It just so happens other parts of the console are all Nichicon capacitors and I will this week check the rest of the console as to
condition of the other caps that were on these boards where the problem was.
Jim


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 Post subject:
PostPosted: Jun Thu 29, 2006 4:54 am 
What brand/model ERS meter would you recomend?


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 Post subject:
PostPosted: Jun Thu 29, 2006 1:24 pm 
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Location: Detroit, MI USA
I use an old Creative Electronics analog ESR tester from the 1970's, which I really like.

There have been very favorable reviews of the Dick Smith ESR tester from Austrilia, available from one or more distributors in North America. Sold as a kit or assembled, most likely the best of the current digital units.

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Dennis

Experience is what you gain when the results aren't what you were expecting.


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 Post subject:
PostPosted: Jun Thu 29, 2006 3:18 pm 
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I have the Dick Smith unit from Australia. It's quite basic and inexpensive, but seems to work just fine. I've been using it for about a year, and am getting fairly comfortable in using it to identify good vs bad electrolytics in vintage equipment.

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 Post subject:
PostPosted: Jun Thu 29, 2006 4:45 pm 
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Location: fairfax station, va, usa
I have the fully built one from Portugal. Happy with it, and it arrived quickly.

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-e


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 Post subject:
PostPosted: Jun Fri 30, 2006 4:14 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 129
Location: Roslyn Heights
Hi Again
I have the same ES meter made by Dick Smith unit from Australia.
Its worked very well for me.
Last I left off I was going to replace the caps that went bad.
I was told that the reasion they went bad was because the cap called for a 4 volt and I replaced them with 16volts at 100uf.
I really have to comment on this as it may be true but I used the same type of capacitor on a different location on the board at the orginal voltage 25volts at 22uf and they too went bad. When I replaced them with xicon they are still spot on as of today and thats from three years ago.
I really feel the capacitors were from a bad run in manufacturing..

OK the big question, and have had different views on this.
I replacd the capacitors that went bad that were 16volt at 100uf with the blue Philps axial ones that I had and all is still fine.
The orginal cap called for a 4 volt at100uf and I replaced it with a 25 volt. Some say its fine in this board and some say there's not enough current for the cap to work proper

This is a light discription of the circuit

The input transistors on these boards are biased off the emitter load of the second transistor and the 125uF capacitor filters the audio off that line so that it's dc bias only. The negative feedback for these amplifiers comes off the third transistor - which is a voltage follower - and ties back to the input transistor's emitter which forms the inverting input.

The voltage at the input bias is pretty low - as can be seen by the original 4 volt capacitor -

Either one is wrong as it isn't a smart move to put higher voltage electrolytics into much lower voltage circuits. They simply don't get enough polarisation and you would have been better off fitting a 6.3 volt in that location.

Any views on this
regards,
jim


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 Post subject:
PostPosted: Jun Fri 30, 2006 4:25 am 
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Location: Detroit, MI USA
I wouldn't use a 160 volt cap, for instance, in a 10 volt circuit. But a 25 volt cap or a 16 volt cap should be fine for your application. You can readily get many brands of electrolytics as low as 6.3 volts, depending on the capacitance. They didn't go bad because they were 25 volt caps, either they were a bad lot as you suspect, or localized heat within the equipment is killing them, or a combination of both.

Personally I will not buy any more Xicon brand caps, the last ones I had (only because Mouser was out of stock on Nichicon on the values I needed urgently at the time) were all over the place with ESR readings on new stock. Most of them read several times the ESR of new stock Nichicons of the same value and voltage.

I think your equipment deserves a premium quality cap if you are going to all the trouble to replace them only to have them fail again in such a short time. I have replaced literally thousands of electrolytics in consumer electronics using Nichicon brand caps and not one failure that I'm aware of. But I frequently see other brands of caps sometimes only a few years old failing with no explanation. Even had some in very new items, almost brand new, that failed open, (apparently) low quality brands of caps that no one has ever heard of.

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Experience is what you gain when the results aren't what you were expecting.


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 Post subject:
PostPosted: Jun Fri 30, 2006 7:36 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 129
Location: Roslyn Heights
Hi Dennis
I agree on replacing the boards with the best capacitor. The console came with Philps capacitors so I wanted to replace them with the same capacitor as I did. This company Neve is known for there sound and it is today still regarded as one of and by many as the best sounding audio console ever made...
And as I said the blue Philps capacitors still test great.
Its the other Philps caps as I stated earlier that went bad in fact when I got them just for the fact they looked different that got to me. As It goes I was right...
I ordered the Xicon 105c At 22uf at 25 because a well known Neve tec strongly advised these as they were axials, that I want to use.These replaced the caps that went bad. All the others on these boards are the blue Philps capactiors.
He did say even though the order was put in as xicon the cap will read Leon TG 105c H127(M).
These still test great and had no trouble from them.
Whats crazy I friend of mine I talked to today says he loves the Xicon he stated that they have a very low ERS and have been very stable.
His caps state on them Xicon. So with all this Who knows?????.
Maybe the problem is today QC is not really a true QC as in days past???
Other parts of the console use Nichion capactiors.
As to my main question, I am safe with the 25 volt caps in place of the 4 or 6 volts cap voltage same value of 100uf.
Thanks for the time in this matter.
Jim


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 Post subject:
PostPosted: Jul Sat 01, 2006 4:57 am 
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Location: Cape Girardeau MO
My opinion for what it is worth is that the higher voltage cap should work fine without going bad in a short amount of time. The fact that they are running on a lower voltage should mean that the caps do not have to work as hard. I think you got a batch of bad caps. If there is a lot of heat inside the unit you may want to consider putting a fan in it to help keep things cool.


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 Post subject:
PostPosted: Jul Sat 01, 2006 6:16 am 
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Location: Roslyn Heights
Thanks for the tips as to my project.
The console has 32 channels, I keep the room very cool. I think you are correct the capacitors were a bad run just for the fact all the others are fine...
What are the odds of me calling Digi Key and getting some sort of Satisfaction? In all there were around 200 caps.

Regards,
jim


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PostPosted: Jul Sat 01, 2006 3:50 pm 
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Location: Detroit, MI USA
My guess would be slim to none after that length of time. You can ask them their opinion of what to do, but unless you are a long established customer with an open account and place $$$ frequent orders, don't expect much from ANY distributor. In my experience it was much better in the past, when distributors would back up the products they sell to their major accounts for a certain limit of time past the manufacturer's warranty period. It would have to be a major problem, such as this one, and for someone who didn't complain very often. But I don't know if that would happen today after even several months have passed.

They can advise you how to proceed, and if really cooperative may inform you whether they have heard similar complaints about the quality of a certain run of parts. Also I think you might have a slight chance by approaching the manufacturer of the parts directly, but only after the distributor declines. Even then they would only give you an equal number of new capacitors at best. Would you really want to install 200 more of the same ones after this experience? Considering that PC boards can only be unsoldered and resoldered a few times before the foil starts to separate and pads lift off the board even with the best techniques and equipment, I would not want to take that chance.

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Experience is what you gain when the results aren't what you were expecting.


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 Post subject:
PostPosted: Jul Sun 16, 2006 12:54 am 
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The Cap Wizard ESR tester is the best on the market


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