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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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I've got a couple of IP cams where the same cap failed.
It's a 15 uF, 100v radial cap spec'd to 105c. But I'm having fits trying to find a replacement where they don't rape me on shipping. Can I shop for something with slightly different specs? i.e. is 100v just an upper limit beyond which the cap will fail... and I could replace it with a 200v or 300v cap? What about uF? Do I use a 20 or 30 uF at my own risk? -- Pete Cresswell |
#2
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On Mon, 07 Apr 2014 06:30:39 -0700, (PeteCresswell) wrote:
I've got a couple of IP cams where the same cap failed. It's a 15 uF, 100v radial cap spec'd to 105c. But I'm having fits trying to find a replacement where they don't rape me on shipping. Can I shop for something with slightly different specs? i.e. is 100v just an upper limit beyond which the cap will fail... and I could replace it with a 200v or 300v cap? What about uF? Do I use a 20 or 30 uF at my own risk? Depends a bit on failure mode. same cap, same location? probably being overstressed either with voltage, which isn't likely because designers understand voltage, but overstressed with excessivae AC ripple current, since most designers don't understand that stuff and simply spec for high temp, like 105C -- you see the thought process here? Therefore *IF* you replace go for same or more uF, same or more voltage [tilt towards more voltage], and definitely LOWEST Resr you can find. ....my opinion only, without looking deeper. |
#3
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On 04/07/2014 07:08 AM, RobertMacy wrote:
On Mon, 07 Apr 2014 06:30:39 -0700, (PeteCresswell) wrote: I've got a couple of IP cams where the same cap failed. It's a 15 uF, 100v radial cap spec'd to 105c. But I'm having fits trying to find a replacement where they don't rape me on shipping. Can I shop for something with slightly different specs? i.e. is 100v just an upper limit beyond which the cap will fail... and I could replace it with a 200v or 300v cap? What about uF? Do I use a 20 or 30 uF at my own risk? Depends a bit on failure mode. same cap, same location? probably being overstressed either with voltage, which isn't likely because designers understand voltage, but overstressed with excessivae AC ripple current, since most designers don't understand that stuff and simply spec for high temp, like 105C -- you see the thought process here? Therefore *IF* you replace go for same or more uF, same or more voltage [tilt towards more voltage], and definitely LOWEST Resr you can find. ...my opinion only, without looking deeper. Is this an electrolytic? Polarized? |
#4
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On 04/07/2014 6:30 AM, (PeteCresswell) wrote:
I've got a couple of IP cams where the same cap failed. It's a 15 uF, 100v radial cap spec'd to 105c. But I'm having fits trying to find a replacement where they don't rape me on shipping. Can I shop for something with slightly different specs? i.e. is 100v just an upper limit beyond which the cap will fail... and I could replace it with a 200v or 300v cap? What about uF? Do I use a 20 or 30 uF at my own risk? Where are you located that shipping is such a cost? As for larger values of capacitance, that may or may not work depending on the job for the original cap. If part of a switching supply then I'd say, no - don't put in a higher value. If part of a linear supply, then a 20 instead of 15 should be OK, but not bigger. Have you contacted the manufacturer to see if they have a service bulletin out on this failure? John :-#)# -- (Please post followups or tech inquiries to the 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." |
#5
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In article ,
"(PeteCresswell)" wrote: I've got a couple of IP cams where the same cap failed. It's a 15 uF, 100v radial cap spec'd to 105c. But I'm having fits trying to find a replacement where they don't rape me on shipping. Can I shop for something with slightly different specs? i.e. is 100v just an upper limit beyond which the cap will fail... and I could replace it with a 200v or 300v cap? What about uF? Do I use a 20 or 30 uF at my own risk? Pete- I saw this same question recently. I did not reply because I thought others had good answers. Basically, the answer "depends"! A higher voltage is acceptable unless the physical size is a problem. Higher capacitance might be OK if it is used as a power supply filter. If it is used as part of a timing circuit, then stay close to the original value. Failures of the same part on multiple devices could be the result of the original manufacturer buying a bad batch and/or counterfeit parts. If your replacements do not solve the problem, it could be due to a poor design that over-stresses the part. Fred |
#6
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John Robertson wrote:
On 04/07/2014 6:30 AM, (PeteCresswell) wrote: But I'm having fits trying to find a replacement where they don't rape me on shipping. Order two of these http://www.digikey.com/product-detai...1968-ND/589709 at 38 cents each from Digi-Key and send them a check. (If the lead spacing or physical size isn't correct, they have three other 15 uF, 100 V, 105 C caps for 36 to 58 cents each.) If you send Digi-Key a check with the order, they will pay for the shipping to the US and Canada. You will be out 49 cents for the stamp. Where are you located that shipping is such a cost? He neglected to say in his first post about this problem. Several people, including me, gave him ideas, which he did not respond to. https://groups.google.com/forum/#!to...ir/Yv9EDsOC9GQ Part of the problem is that I think he wants to buy just two capacitors, so the typical $5-$7 shipping charge is much greater than the parts cost. Matt Roberds |
#7
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On Mon, 07 Apr 2014 09:30:39 -0400, "(PeteCresswell)"
wrote: I've got a couple of IP cams where the same cap failed. I'll assume these were installed in different locations. Therefore, it is unlikely that some major power glitch or overload condition caused the cap to fail. Most likely, all the caps were defective on arrival. If you have some of the same model IP camera where the cap hasn't failed yet, you might consider a pre-emptive cap replacement. It's a 15 uF, 100v radial cap spec'd to 105c. I would be interested in the brand name or better yet, a photo. But I'm having fits trying to find a replacement where they don't rape me on shipping. http://www.ebay.com/itm/321317467092 $3.19 plus $1.00 shipping. Can I shop for something with slightly different specs? Yes. However, if the cap is in a circuit that requires an extremely low ESR, you may have problems with a lower voltage substitute. If this cap is the output filter for a small switching power supply inside the camera, I would stay with the 100v rating. Otherwise, feel free to substitute. However, I doubt that it's in an ESR sensitive circuit. If low ESR was a requirement, then the ideal cap would have a much higher capacitance, and a voltage rating as low as possible. i.e. is 100v just an upper limit beyond which the cap will fail... and I could replace it with a 200v or 300v cap? It probably won't fit. What about uF? Do I use a 20 or 30 uF at my own risk? That depends on the circuit. If it's in a timing circuit, it's a bad idea. If it's a power supply bypass, just about anything will work, unless the designer got clever and used some kind of resonant scheme to improve the ESR at the switching frequency. Hint: The quality of the answers depends heavily on the quality of the information you supply. You left out the maker and model of the camera, the maker of the capacitor, where in the circuit it's used, and under what conditions it is failing. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#8
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Per dave:
Is this an electrolytic? Polarized? I can't find any indication of polarity. I'm not sure what constitutes electrolytic, but when they failed a brownish goo leaked out and solidified. Here are a couple of pix: http://tinyurl.com/manvbbg http://tinyurl.com/n82vgpj -- Pete Cresswell |
#9
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On 04/07/2014 10:34 AM, (PeteCresswell) wrote:
Per dave: Is this an electrolytic? Polarized? I can't find any indication of polarity. I'm not sure what constitutes electrolytic, but when they failed a brownish goo leaked out and solidified. Here are a couple of pix: http://tinyurl.com/manvbbg http://tinyurl.com/n82vgpj That brownish goo on the top of those capacitors is the glue to hold it to the PCB. If the caps leaked it would be at the other end, where the two leads come out of the (usually) black plastic sealed end, not through the aluminum top! These are standard electrolytic caps - if you look at the side closest to the camera you will see the -- band which is the negative. These caps may be OK - if you made the assumption that the brown goo indicated failure - and the problem may be elsewhere... John :-#(# -- (Please post followups or tech inquiries to the 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." |
#10
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"Yes. However, if the cap is in a circuit that requires an extremely
low ESR, you may have problems with a lower voltage substitute." I assume you meant higher there. The old formula y'know : +capacitance +voltage -size -ESR (+temperature + ripple current rating) =price Just mentioning this because since the question was asked, the poster does not know. It may sound strange to some, but in some cases it might be better to use a LOWER capacity. Really, is a switchmode is running at 100 Khz, does it really need a 2,200 uF ? Hell no, they used that value to get the best price on the ripple current/ESR. In some cases maybe they want certain supplies to fall before others on power down, but that's usually not critical enough to worry about and that esotera of designing is usually out the window when the thing is barely out of warranty. If you get a lower value lytic at the same voltage and the same size, it is likely to have lower ESR, no ? Of course if the thing just runs off an AC trnsformer then it's different. If that's the case, don't lower the value. In the case of the OP, if you don't know, just use the original value but select one from Digikey with lower ESR, higher ripple current rating and you should be fine as long as it physically fits. At any rate, here is the Digikey page on it : http://www.digikey.com/product-searc...=0&pageSize=25 The highest priced one is 58 cents. From there, measure what you got, look at the ones that are the size you need and get the one with the highest ripple current rating. And then of course, replace them all. |
#11
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Now that I've seen the pictures, tell you this much, that looks like that conductive glue.
NO, it's not supposed to be conductive... Remove it in all units, it'll eat your solder mask and create all kinds of problems if it is what I think it is. Of course it has been known to fail like that for the last fifteen years, that's why they use it, to sell new cameras when the old ones fail. |
#12
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On Mon, 7 Apr 2014, Jeff Liebermann wrote:
On Mon, 07 Apr 2014 09:30:39 -0400, "(PeteCresswell)" wrote: I've got a couple of IP cams where the same cap failed. I'll assume these were installed in different locations. Therefore, it is unlikely that some major power glitch or overload condition caused the cap to fail. Most likely, all the caps were defective on arrival. If you have some of the same model IP camera where the cap hasn't failed yet, you might consider a pre-emptive cap replacement. It's a 15 uF, 100v radial cap spec'd to 105c. I would be interested in the brand name or better yet, a photo. But I'm having fits trying to find a replacement where they don't rape me on shipping. http://www.ebay.com/itm/321317467092 $3.19 plus $1.00 shipping. Can I shop for something with slightly different specs? Yes. However, if the cap is in a circuit that requires an extremely low ESR, you may have problems with a lower voltage substitute. If this cap is the output filter for a small switching power supply inside the camera, I would stay with the 100v rating. Otherwise, feel free to substitute. However, I doubt that it's in an ESR sensitive circuit. If low ESR was a requirement, then the ideal cap would have a much higher capacitance, and a voltage rating as low as possible. i.e. is 100v just an upper limit beyond which the cap will fail... and I could replace it with a 200v or 300v cap? It probably won't fit. What about uF? Do I use a 20 or 30 uF at my own risk? That depends on the circuit. If it's in a timing circuit, it's a bad idea. If it's a power supply bypass, just about anything will work, unless the designer got clever and used some kind of resonant scheme to improve the ESR at the switching frequency. Hint: The quality of the answers depends heavily on the quality of the information you supply. You left out the maker and model of the camera, the maker of the capacitor, where in the circuit it's used, and under what conditions it is failing. And where he is. No wonder the question sounded familiar, he's the same guy who was asking a similar question last week. Michael |
#13
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"These caps may be OK - if you made the assumption that the brown goo
indicated failure - and the problem may be elsewhere... " True, I didn't consider that. |
#15
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On Mon, 07 Apr 2014 10:55:46 -0700, John Robertson
wrote: ...snip... That brownish goo on the top of those capacitors is the glue to hold it to the PCB. If the caps leaked it would be at the other end, where the two leads come out of the (usually) black plastic sealed end, not through the aluminum top! These are standard electrolytic caps - if you look at the side closest to the camera you will see the -- band which is the negative. These caps may be OK - if you made the assumption that the brown goo indicated failure - and the problem may be elsewhere... John :-#(# like put in backwards? naw, not at 100V, but I've seen such at 6V |
#16
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Per :
Where are you located that shipping is such a cost? He neglected to say in his first post about this problem. Several people, including me, gave him ideas, which he did not respond to. https://groups.google.com/forum/#!to...ir/Yv9EDsOC9GQ Part of the problem is that I think he wants to buy just two capacitors, so the typical $5-$7 shipping charge is much greater than the parts cost. Mea Culpa. You nailed it. Ten bucks to ship two 89-cent caps that weigh less than a half ounce? It's more a matter of principle... that plus thinking that there *must* be a source where shipping charges are more rational. I've had small circuit boards shipped all the way from Guandong Province for zero shipping. OK, that's not "rational"... more like the Chinese government subsidizing their businesses... But at least 60 percent of the stuff I purchase via Amazon.com gets shipped for free at a competitive price. (i.e. shipping/handling is not rolled into the price). But now that you've called me on it... I guess I will go the DigiKey route. -- Pete Cresswell |
#17
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Per Jeff Liebermann:
Hint: The quality of the answers depends heavily on the quality of the information you supply. You left out the maker and model of the camera, the maker of the capacitor, where in the circuit it's used, and under what conditions it is failing. I didn't want to call attention to the maker because these cams work pretty well for their cost (about $100). They are EdiMax IC-3030PoE's as in http://www.edimax.com/en/produce_det...id=8&pl2_id=91 I have one more that has not failed yet. All 3 have had different histories - one of them having survived Hurricane Sandy mounted outdoors in a plastic bag about 25' from the bay. Once I have a supply of those caps - and it turns out that replacing the cap makes the camera work again - I'll buy another IC-3030PoE in a heartbeat. Thanks for the analysis of what values matter when. I think I've learned something worth knowing from all this. -- Pete Cresswell |
#18
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"Can you expand on this Brown Glue issue a bit or provide reference links? "
Look under Mitsubishi glue in reference to TV repair. They used it for a number of years and it caused alot of problems. It starts out white, when it turns brown is when it starts being conductive. They eventually stopped using that type of glue, probably because in the business it was becoming so widely known even some of the consumers knew about it. Other manufacturers used it as well but none in the brownwares business as liberally as Mitsubishi. You could literally stick ohmmeter probes in it and reason it like a resistor, and not always ten megs. I've seen glops of it read like 10 Kohms. After they stopped using it they then went to lytics that leaked electrolyte all over the board, not only becoming conductive but actually eating the copper traces awat. In an RPTV, if that failed to kill the unit, their coolant chamber design was defective enough to leak the ethylene glycol/glycerine coolant mixture on the board and it, given a little time with voltage applied also became conductive and corrosive. So, what Mitsubishi, as well as a few other RPTV manufacturers did, instead of desiging the pressure relief (bladder) correctly, the installed gutters in the sets because it was found that if the coolant leaked on parts of the board woith higher voltage and current, like the horizontal or high voltage, it could cause a fire. Think of what the lawyers would have said ! AQctually I have seen units in which the board actually caught fire but in those cases it did not burn the whole house down. If it had, the road men would have noticed something funny during the initial service call. They're observant that way... As such, even though it is well known all over the industry not to use that type of glue, I am confident that some manufacturers will use that type of glue. Think of what the accountants would say. |
#19
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Y'know, there is no way in hell those things need a 100 volt rating.
Unless they use something like an old iconoscope tube or something. No way. |
#20
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![]() "(PeteCresswell)" wrote in message ... Per dave: Is this an electrolytic? Polarized? I can't find any indication of polarity. I'm not sure what constitutes electrolytic, but when they failed a brownish goo leaked out and solidified. Here are a couple of pix: http://tinyurl.com/manvbbg http://tinyurl.com/n82vgpj -- Pete Cresswell That 'leaked goo' is just glue that the manufacturer has used to stick a radial cap down to the PCB so that it 'pretends' to be an axial type. What checks have you done to establish that the cap is faulty ? ESR ? This is the main check that you always have to do on any suspect electrolytics. Value ? Usually of secondary consideration to ESR. Physically short circuit ? If you are basing your belief that the cap is faulty on what you perceived to be something that had leaked out from within, then there's a very good chance that you are mistaken. Arfa |
#21
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On Monday, April 7, 2014 1:34:13 PM UTC-4, (PeteCresswell) wrote:
Per dave: Is this an electrolytic? Polarized? I can't find any indication of polarity. I'm not sure what constitutes electrolytic, but when they failed a brownish goo leaked out and solidified. Here are a couple of pix: http://tinyurl.com/manvbbg Ahh it looks like one lead of the cap is not soldered into the pcb... (or maybe the solder is only on the other side.) George H. http://tinyurl.com/n82vgpj -- Pete Cresswell |
#22
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Per Arfa Daily:
That 'leaked goo' is just glue that the manufacturer has used to stick a radial cap down to the PCB so that it 'pretends' to be an axial type.... If you are basing your belief that the cap is faulty on what you perceived to be something that had leaked out from within, then there's a very good chance that you are mistaken. Ok, that cuts it. Forget about DigiKey. I'm in this way waaaaay over my head. Just trash these things and buy two more. -- Pete Cresswell |
#23
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scribbled thus:
Did anyone notice that the picture location was displayed on Google Maps !!! On Monday, April 7, 2014 1:34:13 PM UTC-4, (PeteCresswell) wrote: Per dave: Is this an electrolytic? Polarized? I can't find any indication of polarity. I'm not sure what constitutes electrolytic, but when they failed a brownish goo leaked out and solidified. Here are a couple of pix: http://tinyurl.com/manvbbg Ahh it looks like one lead of the cap is not soldered into the pcb... (or maybe the solder is only on the other side.) George H. http://tinyurl.com/n82vgpj -- Pete Cresswell -- Best Regards: Baron. |
#24
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On Tue, 08 Apr 2014 09:16:56 -0400, "(PeteCresswell)"
wrote: Per Arfa Daily: That 'leaked goo' is just glue that the manufacturer has used to stick a radial cap down to the PCB so that it 'pretends' to be an axial type.... If you are basing your belief that the cap is faulty on what you perceived to be something that had leaked out from within, then there's a very good chance that you are mistaken. Ok, that cuts it. Forget about DigiKey. I'm in this way waaaaay over my head. You can fix it with a pair of pliers. The yellow/brown goo becomes conductive after it's been baked for a while. I haven't found a good solvent that softens it yet, that also doesn't destroy components, solder mask, or the PCB. My guess(tm) is that the yellow goo is shorting out something on the PCB under the goo. Do whatever it takes to remove the stuff and see if the camera recovers. If you break the capacitor, I think you can afford these: http://www.ebay.com/itm/321317467092 $3.19 plus $1.00 shipping. Just trash these things and buy two more. http://www.ifixit.com/Manifesto Tossing repairable devices should be a capital crime. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#25
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Jeff, forget about solvents, the best way to get rid of it is like a dental pick.
Then it shoots across the room never to be found UNLESS it is in your house in which case you will find it next time you go to the workshop barefoot. Then the language gets interesting, like - "MOFOUNGAWASKAKMAKYA !". In which case the Enlish translation is "There it is, and now, where is that ****ing AK47 I had stashed around here somewhere ?". For a sp[lit second your mind wants to go kill the guy who brought that infestatious mother****er into your sweet abode. Roaches would be better. And I actually necver saw the movie "Falling Down". |
#26
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To add here, sometimes you get just the right bite on that **** with the pliers and the whole big goop of it comes off nice and clean. Just hope you see nice green copoper under it...
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#27
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On Wed, 9 Apr 2014 20:45:58 -0700 (PDT), wrote:
To add here, sometimes you get just the right bite on that **** with the pliers and the whole big goop of it comes off nice and clean. Just hope you see nice green copoper under it... Yeah, that's how I usually end up doing it. If the yellow/brown goo is stuck mostly to a PCB covered with green solder mask, the solder mask will typically flake off and go with the goo. However, if the goo covers components, wires, or bare PCB, chances of destroying everything under the goo is highly likely. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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