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#11
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Capacitors on graphics cards...
On Wed, 27 Aug 2008 16:02:12 +1200, "~misfit~"
wrote: Somewhere on teh intarweb "kony" typed: On Wed, 27 Aug 2008 00:34:41 +1200, "~misfit~" wrote: Ok, so I have a couple Leadtek WinFast A280 LE AGP 8x VIVO 128MB GeForce ti4200's. I bought them for my machine and my girlfriends (back when I had one) and they cost over NZ$300 each new. They were a significant investment at the time, costing twice as much as the T'bredB Athlon XP CPUs they ran with. My ex's card failed before we split and I put it on the shelf and bought her a 7600GS to replace it. Mine failed not long afterwards and also went on the shelf. I couldn't bring myself to throw them away considering what they cost. Actually, only one is VIVO, the other didn't need to be VIVO and was ~$40 cheaper. The other day I was having one of my periodic clean-outs and I had a good look at them. One of them had a capacitor that was lifting off it's plug. I replaced it and now it'll boot in a machine but periodically the machine crashes. I'm considering replacing all 7 of the non-solid caps and am seeking opinions. Generally those between the 'fets and the load are the more likely to fail, I'm not sure which ones they are. I've uploaded some pics, mainly of the PCI card to see if those things that I think are conductive polymer caps really are. The little ones on the PCI card are electrolytic not polymer. However, there's a pic of the ti4200's there, can you tell me which caps are most likely to be the ones? I can only see what looks like one power MOSFET and it's surrounded by caps. I'd replace the following as pictured, if you don't have enough spare caps on hand to do them all then I'd replace them in waves by number, trying the card after each wave (finishing one card before trying to start the second). http://69.36.166.207/usr_1034/Bugs026-numbered.jpg However, if none of them look even slightly bulged or leaky, I'm less confident that replacing them will make a difference. The yellow one on the card on the left looks like someone already repaired it, it's quite rare to see a manufacturer do what they did putting a larger cap between one original cap's positive pin and another's negative. I've done repairs like that before but never saw it as an original cap placement. I'd replace those first if you have a few spare capacitors lying around or that you could cannibalize off of something else like a dead motherboard (though with known good caps still). I've always been a bit wary of re-using caps as I don't have a multimeter cpable of testing capcitance and, IME, bad caps are the biggest reason for failure for most electronics. True they're one of the most likely causes but usually vent out the top or bottom if they're bad enough to matter. I wouldn't use some ancient socket 7 board for the donor caps though, would tend to stick with Japanese well known brands. There are five 1500uf 6.3V caps on each graphics card and I have a (dead) Asus mobo with seven Nichicon caps on it of the same value. However, the caps on the graphics cards are 8mm diameter with 3.5mm lead spacing and the ones on the mobo are 10mm / 5mm and have very short leads. Maybe I can get them to fit... Maybe. If the leads are very short I doubt you'll be able to make the 5mm spaced ones fit in the 3.5mm locations. Look on the back of the card, sometimes manufacturers put both lead spacings so they have the option of using either cap size. Don't worry so much about the values though, if the original cap is rated for 16V be sure to use a replacement rated for 16V but with any others, use anything rated for 6V up to around 16V and at least 1000uF, if worst came to worst you might even try 470uF caps if they're 10V or 16V. Reusing old parts, and having video cards that don't work, all you're really losing out on is time if you don't want to buy new caps by mail-order. Sometimes even given the best effort there really was something else on the card that was damaged and you have to give up, but having two cards and one at least showing some signs of life, it seems fair odds you can get at least one to work. Something else you might try is taking the solid caps off one if you can't get it to work and putting those on the other one. It's much less likely the solid ones failed. As for the smaller caps, I don't have exact matches in my box of bits although I can get close (albeit with bigger components) but the caps are of unknown quality. If by the smaller ones you mean those with the turquiose band, those are polymer and shouldn't need replaced. The other smaller ones at the top of the picture were like the one you said failed, right? If so they are definitely suspect and again you don't necessarily need exact matches. Generally a manufacturer doesn't use some value because it's all that important, they're trying to strike a balance of reliability and low cost. Just recognize that they seldom use a 16V cap unless the circuit point is at least 12V, unless they had used 16V caps in very many locations and had just wanted to reduce the parts count. Otherwise everywhere else with lower than 16V caps can use a 6V which is the most common you'd find on many old motherboards. Bigger components are fine, so long as you get the leads in the holes with a good solder attachment and they're not touching another part's leads, not so tall that you then can't use an adjacent motherboard slot if you'd needed to. A significantly larger sized higher ESR cap can sometimes be used as a substitute for a smaller low-ESR cap in an emergency, and in those cases it is generally better to use a higher voltage value (within reason, moving to 100V is probably unreasonable) than going with more than triple the capacitance value unless the original cap was a lower-uF polymer type then you may have more margin to use double, 6X the value. It's hardly a science as we don't know the original circuit parameters as built and if the cap doesn't have a significantly lower ESR than the original then a higher uF value may not cause significant enough addt'l surge to matter. Interestingly, it seems that Leadtek must have been going through a rough patch when these cards were produced. Leadtek enjoy a large market presence in New Zealand so consequently I have a few of their cards around from over the years. The oldest is a PCI S3 Trio64V+ with 1MB RAM on-board. The newest is a 7800GT with 256MB RAM. I also have a Leadtek GeForce 2 MX400, an FX5600 and an FX5700. Here's the interesting bit. The old (and I mean 15 years old) PCI card has all solid conductive polymer (CP) capacitors. The GF2 has all ali can (AC) 'wet' caps but was made before the great capacitor swindle at the end of last millenium and is still going strong in daily usage. Are you sure those are solid, conductive polymer capacitors on the old card? In that era they tended to be mostly tantalum (small rectangular yellow surface mounted) or small electrolytics which may or may not have been surface mounted without any vent slits so they did look like solid polymers but often had a black stripe instead of colored to quickly identify which they were. I'm not sure, they just look like it. I've uploaded pics he http://s308.photobucket.com/albums/kk349/misfitnz/ They're electrolytic, as is practically everything with a black strip or that old in an aluminum can. Both of the ti4200's have a mix of CP and AC caps but, interestingly, the mix varies from one card to the other. (They were bought 4 months apart, right after the public furore over the bad caps scandal.) Also interestingly, one of them has two caps replaced by one, bridging from the +ive of one cap stencil to the -ive of the other. (There are two caps on the other PCB.) All three of the later cards I have are fitted with all CP capacitors. Now, I'm thinking that, with the ti4200's, it might be worth replacing the AC caps with new ones and hoping that the cards are fixed. Correct me if I'm wrong but it's unlikely that any other components would have failed causing the cards to fail. They've always been in well ventilated cases and have never been overclocked. Am I right? Silicon gates and resistors should still be fine, chances are, if I replace the AC caps then the cards will work and become reliable again? If the cards were pulled out of the systems the moment they ceased to stay stable there is a good chance they are ok besides the capacitors, but it is still possible that other parts were damaged because without the caps functioning properly the card starts using more current and with ever higher ripple, that can cause the regulation to go out of control. Both cards were pulled when they were failing but working and all other components *appear* to be fine... They seem like good candidates for recapping, it's just that they're old enough at this point that the cost and time weighs against it. Generally what I do when ordering caps for some project is get extras, like a bunch of 8mm and 10mm diameter in 10-12mm size and 20+mm size, then I have extras for other projects so it's not so costly to order exactly what I'd need each time. I would try replacing the caps if it can be done cheaply or at no expense. I could probably do one card using caps I have lying around, salvaged from other components. However, they're all an unknown quantity. Quality, you can search for the brand and model at badcaps.net, or maybe find their spec sheets. You can also look at where they were in the old equipment you pulled them out of, for example if they were in the CPU or memory switching regulation circuits they are probably the right type, and reasonably assumed still viable if they haven't vented... and yet, the same could've been said about the caps still on the video cards that don't look vented so you can only try and see how it goes. $20 seems a bit much unless prices are a lot higher down there and you have to mail-order them. Both actually. We're a small country and economies of scale come into it. Also I have to mail-order or travel a fair distance to a store which may or may not have the caps I require. :-( You could always call them and ask, and see if they'd throw a handful in an envelop for regular postal service delivery to cut down on costs? Sometimes if you say you're a student they might be more accomdating. I'd see if I had an old motherboard lying around with something close enough, that'll fit in the available space. This might be my best option, try it with one of the graphics cards anyway. That's what I usually do on anything that isn't of high value anymore, then I started getting too big a stack of cannibalized motherboards and started using a small torch to pull lots of parts off and throw them into a few plastic containers so I could throw the boards away. Back when I first started replacing caps on mobos I re-used caps on a board I really wanted to keep (a Gigabyte 440BX Socket 370, Coppermine-capable board that had a Promise RAID controller on-board and would run at 133/33MHz FSB/PCI) but I couldn't get it to run stably. I ended up replacing some caps with salvaged caps a few times until I destroyed the board. That put me off re-using salvaged caps. Sometimes there's more than one problem. Failed caps plus slight board or surface mount component cracks then handling the board to fix the caps can make it even worse. Motherboards in particular can be a real lottery, I've tried to keep at least one backup board from every era just in case I need a spare for myself or someone I'd sold a system to. Probably half or more of them now have dead batteries. My general rule of thumb on replacing with new caps is, don't spend the money if a performance upgrade would matter or if the cost exceeds half the value of the equipment, or if the part wouldn't show any signs of life anymore if there aren't any caps horribly deformed or vented, or if you don't really need the part to work... for example I don't know the market down there but I can generally pick up a used video card from some shop or online from a hardware enthusiast FS/FT forum for under $20 if they're not trying to gouge on postage. They're quite fully-featured cards, with monitoring chips on them that tell Speedfan on-die temp, a thermistor between GPU and HS temp and fan speed. They also have a series of three LEDs that tell if they're running in 4x or 8x mode and if there is an AGP slot problem. They've also got some pretty impressive lumps of aluminium on both sides of the cards and the fans are still working and not excessively noisy. So... What do you think? It's not *so* much about the money really, it's more about keeping them out of a landfill somewhere and also justifying the outlay in, ummm, 2002 or so. I'd be quite bummed out if i mail-ordered the caps, fitted them and still had a dead card (or two, the postage on the caps means it'd be more sensible to buy enough for both...) Cheers, and TIA for any input. I don't think it's worth the time, money, and uncertainty of success to try it today. If I already had the caps lying around or that could be cannibalized off a motherboard/etc in a couple minutes time then I might try it... unless you really need a couple AGP video cards and would end up actually spending the $20+ on one if you don't get either of them to work. I don't *need* them per se, although it's always handy to have spares around. I might tinker with one in a day or two using salvaged caps and see how it goes. Thanks for the input mate, You might also pull the heatsinks off to be sure the original thermal material hasn't cooked away over time. |
#12
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Capacitors on graphics cards...
In article , ~misfit~
writes I've always been a bit wary of re-using caps as I don't have a multimeter cpable of testing capcitance and, IME, bad caps are the biggest reason for failure for most electronics. You aren't just testing for capacitance, but need to test for ESR (equivalent series resistance). Failing caps develop high ESR in addition to reduced capacitance, causing them to heat up. This becomes a vicious circle until the capacitor fails. The reduced capacitance results in increased ripple and this is what cooks the MOSFETs and coils. It's not worth buying an ESR meter just to test a few caps. Just swap out all the electrolytics. I wouldn't even bother with the PCI card - that goes to landfill. The ti4200s are worth saving for the sake of half an hour's work, and you'll have the satisfaction of a successful fix. There are five 1500uf 6.3V caps on each graphics card and I have a (dead) Asus mobo with seven Nichicon caps on it of the same value. However, the caps on the graphics cards are 8mm diameter with 3.5mm lead spacing and the ones on the mobo are 10mm / 5mm and have very short leads. Maybe I can get them to fit... Why re-use caps from a motherboard? They are an unknown quantity, and the caps in switching power supplies on mobos have a hard life. Get the right caps new. The 10mm dia ones are 36 pence each on http://rswww.com, part number 449-0851, and the 8mm dia ones are 24 pence each, p/n 526-0954. I'd expect prices to be similar in NZ. I think RS has an Australian presence - worth checking. |
#13
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Capacitors on graphics cards...
Get the right caps new. The 10mm dia ones are 36 pence each on
http://rswww.com, part number 449-0851, and the 8mm dia ones are 24 pence each, p/n 526-0954. I'd expect prices to be similar in NZ. I think RS has an Australian presence - worth checking. RS Australia http://australia.rs-online.com/web/ |
#14
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Capacitors on graphics cards...
On Wed, 27 Aug 2008 11:51:08 +0100, Mike Tomlinson
wrote: In article , ~misfit~ writes I've always been a bit wary of re-using caps as I don't have a multimeter cpable of testing capcitance and, IME, bad caps are the biggest reason for failure for most electronics. You aren't just testing for capacitance, but need to test for ESR (equivalent series resistance). Failing caps develop high ESR in addition to reduced capacitance, causing them to heat up. This becomes a vicious circle until the capacitor fails. The reduced capacitance results in increased ripple and this is what cooks the MOSFETs and coils. It's not worth buying an ESR meter just to test a few caps. Just swap out all the electrolytics. I wouldn't even bother with the PCI card - that goes to landfill. The ti4200s are worth saving for the sake of half an hour's work, and you'll have the satisfaction of a successful fix. There are five 1500uf 6.3V caps on each graphics card and I have a (dead) Asus mobo with seven Nichicon caps on it of the same value. However, the caps on the graphics cards are 8mm diameter with 3.5mm lead spacing and the ones on the mobo are 10mm / 5mm and have very short leads. Maybe I can get them to fit... Why re-use caps from a motherboard? They are an unknown quantity, and the caps in switching power supplies on mobos have a hard life. Get the right caps new. The 10mm dia ones are 36 pence each on http://rswww.com, part number 449-0851, and the 8mm dia ones are 24 pence each, p/n 526-0954. I'd expect prices to be similar in NZ. I think RS has an Australian presence - worth checking. The reason to try reusing capacitors from a motherboard a 1) Capacitors from a motherboard don't generally fail below the needed threshold for the video cards if they aren't visibly vented. 2) Capacitors from a motherboard tend to be larger sized lower ESR than the originals so even if they have had a somewhat hard life, their parameters still tend to fall within that required by the circuit after accounting for aging, unless there were a defective formula that would self-destruct before their expected lifespan had ended. 3) Buying new capacitors is easily worth the cost of one entire video card as misfit has already priced them out at $20 per card. That seems high to me but being in the US I really can't say, I've heard of other areas having significant addt'l expense sourcing other electronic components so it wouldn't be surprising. By trying motherboard caps it may be possible to determine if a capacitor replacement will revive a card and if so, easier to deem whether it is worth buying the capacitors. Further it has been noted that another used card can be purchased for about the same price, so while it would be rewarding to get it working again the path towards one goal seems surer by buying another card the owner claims does work. 4) I suggested it because I do it all the time with good results. The one caveat is that this is almost always when I'm replacing a cap that was visibly vented already, since the others on these two cards have not vented it leaves some uncertainty about the real cause since even a cap that isn't functioning very well would have a signficantly lower filtering requirement with the card just posting and running in 2D mode long enough to see if the card worked at all, versus operating in 3D mode like when gaming. Also, if one has reasonable soldering skills and an ohm-meter doesn't indicate a near short on any caps, the original caps need not necessarily be removed from the card at all, the proposed second cap can be placed on the opposte side of the card and it's leads carefully soldered to the exposed portion of the original cap's leads. Pretty it isn't, but if the original simply isn't a suitably low ESR or capacitance value anymore, the second will tend to be enough to offset that plus it's usually quicker and easier to just tack down a second cap on the rear of the card then desolder it after testing the result. Another thing ~misfit~ might try is fitting the PCI card in a board, setting the board bios to consider PCI the primary video, then installing the AGP card and seeing if the card is detected by nvflash or equivalent. If it shows up it might be worthwhile to try flashing a bios to it to see if it had the EPROM contents corrupted and that is why one, not the one that is just instable but rather the other one, isn't functioning. |
#15
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Capacitors on graphics cards...
Please bear with me, this is getting long but I'm finding it useful. ;-)
I'd selectively snip but I want to save the post for future reference and it will be easier all together. Somewhere on teh intarweb "kony" typed: On Wed, 27 Aug 2008 16:02:12 +1200, "~misfit~" wrote: Somewhere on teh intarweb "kony" typed: On Wed, 27 Aug 2008 00:34:41 +1200, "~misfit~" wrote: Ok, so I have a couple Leadtek WinFast A280 LE AGP 8x VIVO 128MB GeForce ti4200's. I bought them for my machine and my girlfriends (back when I had one) and they cost over NZ$300 each new. They were a significant investment at the time, costing twice as much as the T'bredB Athlon XP CPUs they ran with. My ex's card failed before we split and I put it on the shelf and bought her a 7600GS to replace it. Mine failed not long afterwards and also went on the shelf. I couldn't bring myself to throw them away considering what they cost. Actually, only one is VIVO, the other didn't need to be VIVO and was ~$40 cheaper. The other day I was having one of my periodic clean-outs and I had a good look at them. One of them had a capacitor that was lifting off it's plug. I replaced it and now it'll boot in a machine but periodically the machine crashes. I'm considering replacing all 7 of the non-solid caps and am seeking opinions. Generally those between the 'fets and the load are the more likely to fail, I'm not sure which ones they are. I've uploaded some pics, mainly of the PCI card to see if those things that I think are conductive polymer caps really are. The little ones on the PCI card are electrolytic not polymer. OK, thanks. The only caps I've noticed that look like those before are polymer. Usually IME 'lytics look more like... well, 'lytics really. However, there's a pic of the ti4200's there, can you tell me which caps are most likely to be the ones? I can only see what looks like one power MOSFET and it's surrounded by caps. I'd replace the following as pictured, if you don't have enough spare caps on hand to do them all then I'd replace them in waves by number, trying the card after each wave (finishing one card before trying to start the second). http://69.36.166.207/usr_1034/Bugs026-numbered.jpg However, if none of them look even slightly bulged or leaky, I'm less confident that replacing them will make a difference. Ok. Looking at the card on the right on your pic, the cap that has an arrow pointing to it situated near the connectors is one I soldered in. The original, same specs and brand as the cap you've numbered 1 (330uf, 6.3V), was the only cap on either board that showed any visible signs of deterioration. It had lifted off it's plug to the extent that I'm surprised the plug is still holding in there. As that cap failed and the cap that you've put as number one to replace were identical it wouldn't surprise me if, although visually fine, the other (#1) is way out of spec. They're GSC brand, as are all the other 'lytics, a name I've seen lots of times on caps I've had to replace. The replacement I fitted is a 25V Jenpo. I went with matching the capacitance as long as the voltage was the same or higher and it's all I found in my small collection of caps. I've only bothered keeping caps if either they came out of quality equipment (IBM servers for instance that were 'retired' due to obsolescence, nothing wrong with them) or if I recognise the brand of cap as being a good one such as Nichicon or Rubycon. The yellow one on the card on the left looks like someone already repaired it, it's quite rare to see a manufacturer do what they did putting a larger cap between one original cap's positive pin and another's negative. I've done repairs like that before but never saw it as an original cap placement. I bought that card like that, as a new graphics card in a sealed anti-static bag inside a sealed box. I didn't notice at the time, I was just keen on getting it in my machine to replace the GF 2 MX that I had been using up until then. It wasn't until recently that I even noticed it. I've just examined the other side of the board and it looks like there has never been anything soldered through the other holes so I'd say it came out of the factory like that. Looking at the back of the board they don't appear to be wired in parallel but I suppose they must be. The card worked fine like that for 2 years. That yellow cap is a 680uf/.6.3V component. The two in the same place on the other card are 560uf/4V (polymer) and 330uf/6.3V ('lytic). I'd replace those first if you have a few spare capacitors lying around or that you could cannibalize off of something else like a dead motherboard (though with known good caps still). I've always been a bit wary of re-using caps as I don't have a multimeter cpable of testing capcitance and, IME, bad caps are the biggest reason for failure for most electronics. True they're one of the most likely causes but usually vent out the top or bottom if they're bad enough to matter. I've replaced seemingly perfect caps on non-working mobos (in the VRM area) before and had them work perfectly afterwards. I wouldn't use some ancient socket 7 board for the donor caps though, would tend to stick with Japanese well known brands. No. As I said above, I only keep caps that I think have a good chance of being in spec. There are five 1500uf 6.3V caps on each graphics card and I have a (dead) Asus mobo with seven Nichicon caps on it of the same value. However, the caps on the graphics cards are 8mm diameter with 3.5mm lead spacing and the ones on the mobo are 10mm / 5mm and have very short leads. Maybe I can get them to fit... Maybe. If the leads are very short I doubt you'll be able to make the 5mm spaced ones fit in the 3.5mm locations. Yeah, I've had that problem more times than I care to remember. Look on the back of the card, sometimes manufacturers put both lead spacings so they have the option of using either cap size. LOL, already did, no luck. The irony is, the Asus mobo with the Nichicon caps that I'll probably use as a donor? It has double-spacings to take 8mm or 10mm caps and is fitted with the 10mm ones. Actually I've just found a couple VRM modules out of an IBM Netfinity that have 10mm/1500/6.3 caps on them but appear to be hand-made. There are longer leads, bent over on the back. I might unsolder those as the leads are longer. The single biggest problem I've had, that I often have with replacing caps, is getting them small enough to fit. Just about all replacements I see for sale are physically larger. Don't worry so much about the values though, if the original cap is rated for 16V be sure to use a replacement rated for 16V but with any others, use anything rated for 6V up to around 16V and at least 1000uF, if worst came to worst you might even try 470uF caps if they're 10V or 16V. Reusing old parts, and having video cards that don't work, all you're really losing out on is time if you don't want to buy new caps by mail-order. Sometimes even given the best effort there really was something else on the card that was damaged and you have to give up, but having two cards and one at least showing some signs of life, it seems fair odds you can get at least one to work. I hope so. Both cards will boot but with lines through the BIOS screen (then I turn the PC off). Interestingly, they both show *exactly* the same thing, groups of three vertical green lines in six places across the screen in exactly the same place. Actually, that's a worry. Something else you might try is taking the solid caps off one if you can't get it to work and putting those on the other one. It's much less likely the solid ones failed. Yeah. I'll try to get the VIVO card going first, even though it's the one with the bridged cap. As for the smaller caps, I don't have exact matches in my box of bits although I can get close (albeit with bigger components) but the caps are of unknown quality. If by the smaller ones you mean those with the turquiose band, those are polymer and shouldn't need replaced. OK, I didn't realise that. Isuppose the fact that they're rated at 4V should have been a giveaway. Most lytics I see are 6.3V. They're Sanyo too. The other smaller ones at the top of the picture were like the one you said failed, right? If so they are definitely suspect and again you don't necessarily need exact matches. Yep. As I said above (I should have read down a bit). I'll try to find suitable replacements. It's hard when they're so small though. I'll find some caps somewhere. Generally a manufacturer doesn't use some value because it's all that important, they're trying to strike a balance of reliability and low cost. Just recognize that they seldom use a 16V cap unless the circuit point is at least 12V, unless they had used 16V caps in very many locations and had just wanted to reduce the parts count. Otherwise everywhere else with lower than 16V caps can use a 6V which is the most common you'd find on many old motherboards. Bigger components are fine, so long as you get the leads in the holes with a good solder attachment and they're not touching another part's leads, not so tall that you then can't use an adjacent motherboard slot if you'd needed to. A significantly larger sized higher ESR cap can sometimes be used as a substitute for a smaller low-ESR cap in an emergency, and in those cases it is generally better to use a higher voltage value (within reason, moving to 100V is probably unreasonable) than going with more than triple the capacitance value unless the original cap was a lower-uF polymer type then you may have more margin to use double, 6X the value. It's hardly a science as we don't know the original circuit parameters as built and if the cap doesn't have a significantly lower ESR than the original then a higher uF value may not cause significant enough addt'l surge to matter. All good info, thanks. Interestingly, it seems that Leadtek must have been going through a rough patch when these cards were produced. Leadtek enjoy a large market presence in New Zealand so consequently I have a few of their cards around from over the years. The oldest is a PCI S3 Trio64V+ with 1MB RAM on-board. The newest is a 7800GT with 256MB RAM. I also have a Leadtek GeForce 2 MX400, an FX5600 and an FX5700. Here's the interesting bit. The old (and I mean 15 years old) PCI card has all solid conductive polymer (CP) capacitors. The GF2 has all ali can (AC) 'wet' caps but was made before the great capacitor swindle at the end of last millenium and is still going strong in daily usage. Are you sure those are solid, conductive polymer capacitors on the old card? In that era they tended to be mostly tantalum (small rectangular yellow surface mounted) or small electrolytics which may or may not have been surface mounted without any vent slits so they did look like solid polymers but often had a black stripe instead of colored to quickly identify which they were. I'm not sure, they just look like it. I've uploaded pics he http://s308.photobucket.com/albums/kk349/misfitnz/ They're electrolytic, as is practically everything with a black strip or that old in an aluminum can. Ok. Both of the ti4200's have a mix of CP and AC caps but, interestingly, the mix varies from one card to the other. (They were bought 4 months apart, right after the public furore over the bad caps scandal.) Also interestingly, one of them has two caps replaced by one, bridging from the +ive of one cap stencil to the -ive of the other. (There are two caps on the other PCB.) All three of the later cards I have are fitted with all CP capacitors. Now, I'm thinking that, with the ti4200's, it might be worth replacing the AC caps with new ones and hoping that the cards are fixed. Correct me if I'm wrong but it's unlikely that any other components would have failed causing the cards to fail. They've always been in well ventilated cases and have never been overclocked. Am I right? Silicon gates and resistors should still be fine, chances are, if I replace the AC caps then the cards will work and become reliable again? If the cards were pulled out of the systems the moment they ceased to stay stable there is a good chance they are ok besides the capacitors, but it is still possible that other parts were damaged because without the caps functioning properly the card starts using more current and with ever higher ripple, that can cause the regulation to go out of control. Both cards were pulled when they were failing but working and all other components *appear* to be fine... They seem like good candidates for recapping, it's just that they're old enough at this point that the cost and time weighs against it. Yeah. Time isn't an issue for me as I'm an invalid and have nothing but time. That makes the cost an issue though. :-( Generally what I do when ordering caps for some project is get extras, like a bunch of 8mm and 10mm diameter in 10-12mm size and 20+mm size, then I have extras for other projects so it's not so costly to order exactly what I'd need each time. Yeah, I've done that to a certain extent. It's really hard to get caps here though. It seems that all manufacturers source their components offshore which leaves hobbyists high and dry as far as locally sourced components go. I was after some caps a couple years ago to repair a mobo and simply couldn't get any suitable anywhere I looked here. I contacted the NZ Rubycon agent and asked. They said they'd get back to me by email. I got an email a week later saying that they didn't have stock in NZ and there'd be a 2 month lead-time for stock ex-Japan. I said OK, I want some. They replied a week later saying it'd be a minimum order of 1,000 units payable in advance. I said, OK, how much would that cost me? I never heard back, despite re-sending the email weekly for a month. In the end I got a handful from Badcaps.net, sent to a friend in the US as they wouldn't post to here and he sent them on to me. Bloody expensive. I would try replacing the caps if it can be done cheaply or at no expense. I could probably do one card using caps I have lying around, salvaged from other components. However, they're all an unknown quantity. Quality, you can search for the brand and model at badcaps.net, or maybe find their spec sheets. You can also look at where they were in the old equipment you pulled them out of, for example if they were in the CPU or memory switching regulation circuits they are probably the right type, and reasonably assumed still viable if they haven't vented... and yet, the same could've been said about the caps still on the video cards that don't look vented so you can only try and see how it goes. Cheers. $20 seems a bit much unless prices are a lot higher down there and you have to mail-order them. Both actually. We're a small country and economies of scale come into it. Also I have to mail-order or travel a fair distance to a store which may or may not have the caps I require. :-( You could always call them and ask, and see if they'd throw a handful in an envelop for regular postal service delivery to cut down on costs? Sometimes if you say you're a student they might be more accomdating. It seems that even the places that cater to hobbyists are getting gouged. Anywhere that stocks them seem to charge a minimum of a buck a cap, going up to 3 bucks and have a minimum frieght price. That's why I enquired about getting a batch from Rubycon. I figured I could either re-cap some boards to make my money back or advertise some of the surplus in the local comp group.. I'd see if I had an old motherboard lying around with something close enough, that'll fit in the available space. This might be my best option, try it with one of the graphics cards anyway. That's what I usually do on anything that isn't of high value anymore, then I started getting too big a stack of cannibalized motherboards and started using a small torch to pull lots of parts off and throw them into a few plastic containers so I could throw the boards away. Heh! I had a big cleanout a while back, kept a stack of boards to cannabalise but got sick of it after a short time. I don't have a torch and it was tedious removing them with my 30W soldering iron. Back when I first started replacing caps on mobos I re-used caps on a board I really wanted to keep (a Gigabyte 440BX Socket 370, Coppermine-capable board that had a Promise RAID controller on-board and would run at 133/33MHz FSB/PCI) but I couldn't get it to run stably. I ended up replacing some caps with salvaged caps a few times until I destroyed the board. That put me off re-using salvaged caps. Sometimes there's more than one problem. Failed caps plus slight board or surface mount component cracks then handling the board to fix the caps can make it even worse. Motherboards in particular can be a real lottery, I've tried to keep at least one backup board from every era just in case I need a spare for myself or someone I'd sold a system to. Probably half or more of them now have dead batteries. I keep a few spares too. I'm not "in the business" but I've sold a few second-hand systems and built a few new systems to order for folks. I try to keep a few spares on-hand. I guess that's part of the motivation behind trying to fix these graphics cards. Handy to have a reasonably-powerful spare card or two on hand. My general rule of thumb on replacing with new caps is, don't spend the money if a performance upgrade would matter or if the cost exceeds half the value of the equipment, or if the part wouldn't show any signs of life anymore if there aren't any caps horribly deformed or vented, or if you don't really need the part to work... for example I don't know the market down there but I can generally pick up a used video card from some shop or online from a hardware enthusiast FS/FT forum for under $20 if they're not trying to gouge on postage. I just paid NZ$45 on the local version of ebay (trademe.co.nz) for an FX5700 in good condition, all polymer caps and with original box, manual, driver CDs etc. GF2's still regularly fetch $25 each. You can get cheaper if you're prepared to buy items where they say "untested, working when stored, no warranty" but I know of people who sell duds that way and can't afford to gamble. They're quite fully-featured cards, with monitoring chips on them that tell Speedfan on-die temp, a thermistor between GPU and HS temp and fan speed. They also have a series of three LEDs that tell if they're running in 4x or 8x mode and if there is an AGP slot problem. They've also got some pretty impressive lumps of aluminium on both sides of the cards and the fans are still working and not excessively noisy. So... What do you think? It's not *so* much about the money really, it's more about keeping them out of a landfill somewhere and also justifying the outlay in, ummm, 2002 or so. I'd be quite bummed out if i mail-ordered the caps, fitted them and still had a dead card (or two, the postage on the caps means it'd be more sensible to buy enough for both...) Cheers, and TIA for any input. I don't think it's worth the time, money, and uncertainty of success to try it today. If I already had the caps lying around or that could be cannibalized off a motherboard/etc in a couple minutes time then I might try it... unless you really need a couple AGP video cards and would end up actually spending the $20+ on one if you don't get either of them to work. I don't *need* them per se, although it's always handy to have spares around. I might tinker with one in a day or two using salvaged caps and see how it goes. Thanks for the input mate, You might also pull the heatsinks off to be sure the original thermal material hasn't cooked away over time. Already done. :-) Cheers, -- Shaun. DISCLAIMER: If you find a posting or message from me offensive, inappropriate, or disruptive, please ignore it. If you don't know how to ignore a posting, complain to me and I will be only too happy to demonstrate... ;-) |
#16
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Capacitors on graphics cards...
Somewhere on teh intarweb "kony" typed:
On Wed, 27 Aug 2008 18:30:50 +1200, "~misfit~" wrote: Somewhere on teh intarweb "Phil Weldon" typed: '~misfit~' wrote, in part: I could probably do one card using caps I have lying around, salvaged from other components. However, they're all an unknown quantity. _____ Write down the identification letters and numerals on a capacitor. Enter this as a search string in Google. You will likely get some hits that will identify the capacitor type, maximum working voltage, and capacitance. Only the electrolytic high capacitance (200 micro-farad or more) units in a switching voltage converter/regulator are likely to have gone bad. The proper replacements must be low ESR (Equivalent Series Resistance) parts. If the ESR is too high for the purpose an electrolytic capacitor will overheat, the electrolyte will expand, and the top will pop (or at the least the internal structure will rupture and the the capacitor will open or short.) Thanks Phil. I've done a few capacitor replacements on motherboards and always get Low ESR parts. I've always thought that there was really only three other things that I needed to know to match them up (besides size) being capacitance, voltage and temp rating. True, but those don't necessarily need to match. On any decent low-ESR cap it will be 105C temp rated or higher, that's almost automatic. Voltage, generally you have a tiny penalty going to significantly higher voltage than needed, but practically speaking it doesn't matter, rather what size it is would. Keep in mind that often when an electrolytic is used, they use a certain uF value not because it needs that, they use that uF value because a smaller uF value cap has higher ESR (assuming still within the same family of capacitor). This can often be seen when a manufacturer has substituted a solid polymer for an electrolytic or vice-versa, that the electrolytic is always a higher uF value if they had any hope of it remaining a functional circuit. So basically, with a low ESR electrolytic cap that is rated for 16V or less, you could get away with trying anything small enough to fit, the larger the better since you wouldn't be able to get one to fit if it were so large to create excessive inrush current. For example if one were a 6V, 2200uF value, you could probably get away with using a 16V, 1000uF, a 10V 1500uF, or higher uF per voltage. Depends on the cap, and design since some caps may be in parallel. As for voltage, if you have an old board lying around (with an AGP slot of course) put the card in, turn the system on, and measure the voltage across the cap leads. Most will be below 6V so 6V caps are a practial value to use. Some might be at 12V but When I said "unknown quantity" above I meant that I don't know if they're still within spec as they're salvaged components taken from used, usually non-working circuits. I mean, I know that, if they're Rubycon, Nichicon, Sanyo or Teapo that they're likely to be fine but other than that I have no way of testing them Usually caps do vent if they're a failure point in the circuit. At worst you make your best guess about which replacements are ok, solder them in, probe their leads for continuity to be sure there isn't a short (observing polarity, meter will beep for a moment as the cap charges), then put in a non-valuable motherboard to test the result. Thanks for the info, all good. :-) Cheers, -- Shaun. DISCLAIMER: If you find a posting or message from me offensive, inappropriate, or disruptive, please ignore it. If you don't know how to ignore a posting, complain to me and I will be only too happy to demonstrate... ;-) |
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Capacitors on graphics cards...
On Thu, 28 Aug 2008 00:32:18 +1200, "~misfit~"
wrote: They're GSC brand, as are all the other 'lytics, a name I've seen lots of times on caps I've had to replace. The replacement I fitted is a 25V Jenpo. I went with matching the capacitance as long as the voltage was the same or higher and it's all I found in my small collection of caps. I've only bothered keeping caps if either they came out of quality equipment (IBM servers for instance that were 'retired' due to obsolescence, nothing wrong with them) or if I recognise the brand of cap as being a good one such as Nichicon or Rubycon. Being GSC, I'd expect to have to replace all of those for longer term use. Generally what I do when ordering caps for some project is get extras, like a bunch of 8mm and 10mm diameter in 10-12mm size and 20+mm size, then I have extras for other projects so it's not so costly to order exactly what I'd need each time. Yeah, I've done that to a certain extent. It's really hard to get caps here though. It seems that all manufacturers source their components offshore which leaves hobbyists high and dry as far as locally sourced components go. I was after some caps a couple years ago to repair a mobo and simply couldn't get any suitable anywhere I looked here. I contacted the NZ Rubycon agent and asked. They said they'd get back to me by email. I got an email a week later saying that they didn't have stock in NZ and there'd be a 2 month lead-time for stock ex-Japan. I said OK, I want some. They replied a week later saying it'd be a minimum order of 1,000 units payable in advance. I said, OK, how much would that cost me? I never heard back, despite re-sending the email weekly for a month. In the end I got a handful from Badcaps.net, sent to a friend in the US as they wouldn't post to here and he sent them on to me. Bloody expensive. I suppose it depends on how many you need, how you need them shipped, but I thought I vaguely recalled our US Postal Service will deliver a large envelop for a little under $10 USD. A better (cheaper) place to get some other good brands (just not Rubycon) might be electronics houses like Digikey or Mouser. Depending on what the cap size is, sometimes they're still around a dollar a piece (in Qty. 10+) for the larger ones I've sometimes used in power supplies, though probably closer to $0.25 each per 10 in the smaller sizes you're dealing with. You could always call them and ask, and see if they'd throw a handful in an envelop for regular postal service delivery to cut down on costs? Sometimes if you say you're a student they might be more accomdating. It seems that even the places that cater to hobbyists are getting gouged. Anywhere that stocks them seem to charge a minimum of a buck a cap, going up to 3 bucks and have a minimum frieght price. That's why I enquired about getting a batch from Rubycon. I figured I could either re-cap some boards to make my money back or advertise some of the surplus in the local comp group.. I'd see if I had an old motherboard lying around with something close enough, that'll fit in the available space. This might be my best option, try it with one of the graphics cards anyway. That's what I usually do on anything that isn't of high value anymore, then I started getting too big a stack of cannibalized motherboards and started using a small torch to pull lots of parts off and throw them into a few plastic containers so I could throw the boards away. Heh! I had a big cleanout a while back, kept a stack of boards to cannabalise but got sick of it after a short time. I don't have a torch and it was tedious removing them with my 30W soldering iron. I can imagine it would be. I've used an iron for something now and then that was still on a board but usually just heat a big area with a torch and slap the side of a board against a piece of plywood and a bunch of stuff falls off. I don't care much if I get everything because I've had a source of dead boards from some shops so it's really more about putting the least amount of work possible into doing it. Plus it really sticks when the board is heated by a torch, has to be done outside. I just paid NZ$45 on the local version of ebay (trademe.co.nz) for an FX5700 in good condition, all polymer caps and with original box, manual, driver CDs etc. GF2's still regularly fetch $25 each. You can get cheaper if you're prepared to buy items where they say "untested, working when stored, no warranty" but I know of people who sell duds that way and can't afford to gamble. I have to keep reminding myself that converts to less, about 1:0.7 IIRC, in US:NZ dollars... so the latter would only be $17.50 USD which is not so bad, almost getting to the point where the shipping cost approaches half the card cost. |
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Capacitors on graphics cards...
Somewhere on teh intarweb "Mike Tomlinson" typed:
In article , ~misfit~ writes I've always been a bit wary of re-using caps as I don't have a multimeter cpable of testing capcitance and, IME, bad caps are the biggest reason for failure for most electronics. You aren't just testing for capacitance, but need to test for ESR (equivalent series resistance). Failing caps develop high ESR in addition to reduced capacitance, causing them to heat up. This becomes a vicious circle until the capacitor fails. The reduced capacitance results in increased ripple and this is what cooks the MOSFETs and coils. It's not worth buying an ESR meter just to test a few caps. Just swap out all the electrolytics. I wouldn't even bother with the PCI card - that goes to landfill. The ti4200s are worth saving for the sake of half an hour's work, and you'll have the satisfaction of a successful fix. There are five 1500uf 6.3V caps on each graphics card and I have a (dead) Asus mobo with seven Nichicon caps on it of the same value. However, the caps on the graphics cards are 8mm diameter with 3.5mm lead spacing and the ones on the mobo are 10mm / 5mm and have very short leads. Maybe I can get them to fit... Why re-use caps from a motherboard? They are an unknown quantity, and the caps in switching power supplies on mobos have a hard life. Get the right caps new. The 10mm dia ones are 36 pence each on http://rswww.com, part number 449-0851, and the 8mm dia ones are 24 pence each, p/n 526-0954. I'd expect prices to be similar in NZ. I think RS has an Australian presence - worth checking. Ok, thanks. I have the NZ rs-online bookmarked: http://newzealand.rs-online.com/web/ Also I actually have their new (April '08 - March '09) ~3,000 page printed catalogue next to my desk. I've been registered with them for years but have found it seems that I have too little knowledge to find the parts I need. Hence, although I get their emails regularly and a couple weeks ago requested their catalogue (hoping it'd be easier to find the parts I need) I've never ordered from them. The thing that's been confusing me is that I've been unable to find "Low ESR" caps and both of those you mention don't say that they're low ESR. How am I supposed to know? In their catalogue they list various electrolytics as being suitable for hifi crossovers and other various uses but none of their catgories say "low ESR" or "suitable for computer components". Oh, NZ$1.46 and $1.09 each respectively in lots of 5+. (About right considering the exchange rate.) Fright (LOL, typo for freight, quite apt) is a whole other ballgame. I really need to order a large bunch to make it viable. However, I also need to know that what I'm ordering are the correct parts. As mentioned previously, I'm poverty-stricken (otherwise I wouldn't be tinkering with these old cards) and can't afford mistakes. Cheers, -- Shaun. DISCLAIMER: If you find a posting or message from me offensive, inappropriate, or disruptive, please ignore it. If you don't know how to ignore a posting, complain to me and I will be only too happy to demonstrate... ;-) |
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Capacitors on graphics cards...
Somewhere on teh intarweb "Robert McMillan" typed:
Get the right caps new. The 10mm dia ones are 36 pence each on http://rswww.com, part number 449-0851, and the 8mm dia ones are 24 pence each, p/n 526-0954. I'd expect prices to be similar in NZ. I think RS has an Australian presence - worth checking. RS Australia http://australia.rs-online.com/web/ Thanks Robert, I have the NZ site bookmarked. See my reply to Mike. Cheers, -- Shaun. DISCLAIMER: If you find a posting or message from me offensive, inappropriate, or disruptive, please ignore it. If you don't know how to ignore a posting, complain to me and I will be only too happy to demonstrate... ;-) |
#20
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Capacitors on graphics cards...
On Fri, 29 Aug 2008 12:20:05 +1200, "~misfit~"
wrote: The thing that's been confusing me is that I've been unable to find "Low ESR" caps and both of those you mention don't say that they're low ESR. How am I supposed to know? Usually, low-esr is a prominent feature of a cap and will be mentioned. If a daft seller doesn't describe it well enough you are left going to the cap manufacturer's website and consulting the spec sheet. If the manufacturer doesn't have an online presence or spec sheet, or if that doesn't mention low-ESR, you may assume it isn't. |
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