MMM problem

[BrianG]

Originally Posted by J57ltr

It's amazing how many parts Castle uses that we also use at work. We have a lot of problems with the Tant. caps shorting out. Next the Electrolytics will start pooching out.

We have a switching power supply that is made by another manufacturer and after 6 months to 2 years they fail. They are all low ESR. Jamicon and Hermei are the ones we have the most problems with, and switched to Nicholsen(sp) and stopped having problems. There are 3 470 uf 1 1000 uf and a 2200 uf that always fail at the same time. Although we still have a bunch still come in for repair that used the old caps before we found the problem. In the last 2 years we have yet to have a repaired board come back (with a problem), at least I don't consider a blown fuse with the spare right on the board a problem since it fuses the output of the power supply itself, so if it's blown it's another card and it's usually a Tant. cap or one of the other surface mount caps that are shorted.

Jeff

That is reminiscent of the problems with computer motherboards several years back. I forget the full details, but was related to the electrolyte formula being "bad" or something. Would work fine at first, but would fail fairly soon. Motherboard caps would start puffing or even pop (and that stinks).

[J57ltr]

Originally Posted by BrianG

(and that stinks).

Like peanut oil


Yup,

And what got us was that all of a sudden we had a rash of power supplies come back, then it was 10 to 15 a week. After reaserching it we couldn't figure it out the ones used were the same MTBF and temp rating (5K hours @ 105C IIRC) as the ones we use now. When we first started getting them in most were out of warranty, so we would replace the whole PS and send them back (to the customer) then we started getting them after 6 months or less. Then it was back and forth with our source and finally decided to use the other cap.

I remember having a couple of computer power supplies Pop on me, took them apart and had one that the case had completly came out and was rattling around with the "streamer" of the plates and paper in it.

My Daughters Barbie DVD player started acting weird and acting up so I took it apart and found a pooched cap 16V 1000uf (and her "Enchanted" DVD the only one she has ever "lost", not bad for a 4 year old), so I replaced it and it's working great now.

I haven't had a motherboard (cap related problem), but I don't upgrade my computer every 30 minutes either. Plus I usually build it myself using an Acer or my last one was a popular brand from Frys (can't remember the name).

I do a lot of tech support calls so I always ask the customers tech to check the power supply if I suspect it's the problem and ask if the top of the caps are flat or domed and if they see anything leaking fron the slits on top, although sometimes I have seen them with the rubber plug where the leads come out actually push the shell up over the rubber part.

Jeff

[himalaya]

Actually I saw no reason why CC still uses tantalum caps in its products, they can be replaced by MLCCs or multi layer ceramic capacitors, which to my experience is far more reliable, they contain no liquid, no poly material, just ceramic and metal. They seem never fail unless you beat it with a hammer.