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| Thread ID: 53965 | 2005-02-01 03:38:00 | Capacitor Source | linw (53) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 320060 | 2005-02-01 11:19:00 | Motherboards end up on the scrap heap for a variety of reasons, not all because of capacitor failure, and certainly not because of old age, mostly they have just been superceded by a newer model and replaced by the owner. I know that all equipment has an M.T.B.F (mean time before failure) but you will find by just examining the power supply rail in question with an oscilloscope, whether or not the E.S.R is low enough to do the job by the amount of ripple. By putting capacitors in parallel you can lower the overall E.S.R, the only reason not to do this is because of physical size restraints. So if you can't get the correct capacitor, this solution will work in the interim. If the capacitor E.S.R is too high the capacitor will get hot and the resulting pressure, bulging and venting of electrolyte will further lower the E.S.R in a runaway effect resulting in the failure that you have already seen exhibited. You can compare similar capacitors on the board to check the temperature is acceptable. The reason I have posted this information is because I have done a fair amount of design work on switching regulator power supplies and I am fairly confident of my knowledge in this area. Of course the ideal would be to get the correct part, but there are other acceptable solutions. |
zqwerty (97) | ||
| 320061 | 2005-02-01 11:30:00 | More here: forums.pcworld.co.nz |
zqwerty (97) | ||
| 320062 | 2005-02-01 11:56:00 | N.B. M.T.B.F. for electrolytic caps should be approx 64kh @ 55C, this would be about 7 years running 24 hours a day. This time reduces considerably the closer the running temp is to 105C (2kh). |
zqwerty (97) | ||
| 320063 | 2005-02-01 11:59:00 | get the low esr caps from jaycar. I replaced 18 bung caps on a motherboard that was given to me, and now it goes hard once more. Bung socket A mobo - free Soldering skills - earnt over time (Dad started me early) Replacement caps from jaycar - $10.30 One and a half hours of my time - free Getting a super solid mobo for essentially ten bucks - priceless dont worry if the values dont match exactly, so long as the uF rating is AT LEAST the original rating and not completely overboard (eg you wouldnt replace a 10uF cap with a 1F cap ;)), and the voltage rating doesnt matter, so long as it is equal to or higher than the original rating. For example I was replacing 1500uF 6.5V caps, in the end I got 1500uF 10V caps... |
whetu (237) | ||
| 320064 | 2005-02-01 11:59:00 | Well this guy (www.rawiriblundell.com) used some capacitors from JayCar to fix up a dead motherboard. | Jeremy (1197) | ||
| 320065 | 2005-02-01 18:33:00 | He's just blown his own trumpet :-) | PaulD (232) | ||
| 320066 | 2005-02-01 18:51:00 | i would just get them from rs or farnell, both of them should stock those components or be able to source them for you for a price | Budda (2736) | ||
| 320067 | 2005-02-01 19:28:00 | I'd throw out the M/B and buy a new one. Jack |
JJJJJ (528) | ||
| 320068 | 2005-02-02 03:09:00 | Thanks for input . I have had a closer look at my board and noticed that the 7 X 1500UF CPU ones are Panasonic so I won't touch them . The rest are GSC . Only the one 3300UF 6 . 3V has crapped out . There are two other 3300's so I will probably just change these 3 and keep a close eye on the others . Farnells have 3300 at 10V (panasonic) $3 . 39 + GST each . Unfortunately, Jaycars don't have a 3300 one . (But my subbed 2200 is still working fine!) . Cheers, Lindsay . |
linw (53) | ||
| 320069 | 2005-02-02 03:20:00 | Good thinking. They will have come from the same batch. You've got the board out, it's as easy to do three as one. | Graham L (2) | ||
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