Choosing the right Capacitors - Page 1
Forum section: electronics / repair

author: waoj
author_rank: Contributor
timestamp: November 28, 2023, 11:38:34 pm
content: I bought a lovely ATX power supply in 2006 that has kept ticking until now. I remember I chose this one because it came with individual testing and certification paperwork. signed, embossed. And I don't regret it. 17 years. I can't think of much other electronics I have that have lasted that long, in near continuous use unless you count mains cabeling in the walls. Maybe a pole transformer outside, but maybe not honestly....https://photos.app.goo.gl/fGcDj8s1BNUDWjZJ8http://www.pcpowerandcooling.com/Several electrolytic capacitors were bubbling, and I pulled them and found a couple burnt out on bottom. I pulled every one that looked suspect, plus any others of the same dimensions.All in all, I extracted:9x 2200uf 16v sc105degC 12/05 TEAPO green1x 4700uf 16v sc105degC 04/06 TEAPO green2x 3300uf 6.3v sc105degC 08/05 TEAPO green1x 1500uf 10v sz105degC 12/05 TEAPO blueI went on mouser to start picking out the replacements, and I saw "Hours" in their search. but the numbers were conspicuously low. 2000, 5000, 10000. Even 10k is just a year and change. Surely they're made to last longer than a year? The ones I'm replacing lasted about 150k hours before two of them went.The spec sheet even says "Long life, up to 10,000 hours"https://www.mouser.com/datasheet/2/447/KEM_A4010_EST-3316716.pdfDoesn't sound very long to me. I want a damn socket if its going to go out in a year. not worth heating up an iron that often.I just went tohttps://www.mouser.com/c/?q=capacitor%204700uf%2016v&sort=pricing&qty=1and put in Vishay (name cred), radial, high temp. Any more to it than that guys?What recommendations would you have if I want to get another 17 years out of this thing post repair. It didn't even have the 'warranty void' sticker if removed on the case. It's a keeper!How would you source new caps for something like this. I "can't" replace all of them. it's got a super dense riser board set up and I don't know how I could unsolder the riser boards peacefully. but fortunarely everything suspect looking was accessible. Thanks PC Power and Cooloing!One last question. Is is simply age that kills these things, or age while powered on? if I find old (but unused) inventory somewhere, should I avoid it?

author: ataradov
author_rank: Super Contributor
timestamp: November 28, 2023, 11:56:42 pm
content: That life time is for 105 C. And this is a very long life time at that temperature. Usually life time doubles for every 10 C decrease in temperature. So, it would be 40000 hours at 85 C.And how long they practically last is different from what manufacturer guarantees. Things usually last longer, since they would include some margin there.

author: wraper
author_rank: Unknown
timestamp: November 29, 2023, 12:30:25 am
content: Quote from: ataradov on November 28, 2023, 11:56:42 pmAlso it's at maximum ripple current. There are plenty of capacitors rated just for 1000 hours and they usually last for decades when under light load. Original Teapo SC is rated for 3000 hours, SZ for 2000 hours.https://nishioka.com/misc/teapo-sc.pdfhttps://jamicon.teapo.com/upload/Capacitor/Series/SZ.pdfYou don't need more than 105oC capacitors, generally they are for different uses, for example electronic ballasts that run very hot, or automotive. You need high ripple current rating and LOW ESR that are not worse than original. KEMET EST meets ripple current requirement for Teapo SC (not SZ) replacement but ESR is a bit worse, they will work but are not an optimal choice. For example you can use Panasonic FM or FR to replace both types, both are significantly better than original.As of practicality of keeping this PSU, it's questionable. Modern PSUs are much more efficient, even if repair was free, long term most likely you will pay more in additional electricity cost than the cost of a new good quality PSU. Especially if you live in area with high electricity price.

author: waoj
author_rank: Contributor
timestamp: December 01, 2023, 05:15:30 pm
content: well after some more thought, I decided not too fix it. I'll keep the connectors but toss the box and I ordered a new one with a TEN year warranty now. Modular will let me relatively easily build the exact cables I want/need without voiding the warranty, and GPUs use more wires now for whatever reason, so a new PSU will accommodate that better into the future and be more power efficient if I ever start having to pay for power. Today I get to host it at a colo in town in exchange for helping them out with tickets from time to time.

author: Jwillis
author_rank: Super Contributor
timestamp: December 01, 2023, 08:33:36 pm
content: For theKemetyou need to read page 14 of the data sheet. The graph will indicated the varying life expectancy based on operating temperature.You can usually find such information in most capacitor data sheets or use the formula provided on page 14.