Capacitor markings

[krazzzzykay]

I hope I have posted this in the right section.

I am replacing a bad cap on a advent 9115 mobo,this is my first cap replacement.
I have removed the cap from the board and I'm going about the process of sourcing a new one.

My problem is that the cap I'm replacing is an OSCON and after doing some research I have come to the conclusion that to replace this cap with anything other than an OSCON cap would be a mistake.

Radionics is the only place locally that supply caps, and do not supply the one I need. although I did find a different cap with the same voltage and uf marking but it was not an OSCON. - http://radionics.rs-online.com/web/s...571947&x=0&y=0

The closest OSCON they have is a 330uf - http://radionics.rs-online.com/web/s...883165&x=0&y=0

I assume I cant use either of those ?

I'm looking for a SANYO OSCON SP 390uf 6.3v!

I found a supplier on eBay - http://cgi.ebay.ie/ws/eBayISAPI.dll?...#ht_3807wt_973 with one issue which I need answering.

The picture on the eBay suppliers site say 105c 81 and the one I removed from the board has written on it 105c 99.

what are the 81 and 99 meanings ?
I assume they have something to do with the operating temperature ?
can I use the one on eBay in place of the one I removed from the mobo?

[yyonline]

Re: Capacitor markings

It doesn't necessarily have to be another OSCON cap, but definitely replace with another solid polymer cap.

Don't use the 390uF Panasonic FC. It's a reliable capacitor, but not suited for replacing the OSCON.

330uF is close enough in value that it shouldn't cause any issues. Generally, you want to stay within +- 20% of the original value. 330 is within 20% of 390 (312-468), so it's probably ok to substitute that.

Watch out for counterfeit products on eBay... Sanyo is one of the brands for which there are a lot of fake products out there.

http://cgi.ebay.com/4-NCC-PS-6-3V-39...item45ef55950c
I've bought items from that seller before, and all were legit. Chemicon PS series would be a suitable replacement for OSCON SP. However...the PS series has thick leads, so make sure the holes on the board are large enough to fit the leads through.

88 and 99 are probably manufacturing/date codes of some sort.

[yyonline]

Re: Capacitor markings

That said...why has the OSCON gone bad? Those are solid polymer capacitors, and very unlikely to fail unless physically damaged.

[krazzzzykay]

Re: Capacitor markings

I was having intermittent power problems with the laptop and then it just wouldn't turn on and didn't seem to be charging.

At first I thought it was a bad DC jack as there was an electric sound coming form the DC jack when moved. (the jack seems to damaged also and is being replaced)

I took the board out of the casing and found a brown crusty substance on the casing and the board, at first I thought my friend had spilled coke or something similar on the board. but after some research online I discovered this could be a bad cap leaking electrolite.

One of the caps on the board had a lot of this brown stuff on it.
I got the multi meter out and tested 2 other caps on the board of the same value and the results differed from the damaged cap (I'm no expert with a multi meter).

I think that the leaked electrolite may have damaged the board causing the DC jack to short, but am hopping it did not damage it so much that I can not repair it.

thanks for the info

[yyonline]

Re: Capacitor markings

Any chance you could post a picture?

The OSCON capacitors do not have liquid electrolyte, therefore, there is nothing to leak out of them. So, this residue you're seeing is either something else, or could be electrolyte from a different non-OSCON capacitor.

For identifying it, a picture would be most helpful.

How did you test the capacitors with a multimeter? What and how did you measure? Capacitors can't be tested with an ordinary multimeter, but some specialized high-end ones can.

[krazzzzykay]

Re: Capacitor markings

Just after taking a second look at the casing and its possible there was something spilled on the laptop, I'm guessing this could have then caused the damage to the cap?

It is likely the mobo could be completely useless now, but if there was something spilled on the laptop it did work for a period after, so I will continue with my repair attempt and hope that it was just the cap that was damaged.

[krazzzzykay]

Re: Capacitor markings

I cant post a picture right now but will try get some up later

I tested with the multi meter measuring in ohm's - http://www.repairfaq.org/sam/captest.htm

after testin the cap now out of the board my results differ form what they were when the cap was in the board.

2 undamaged caps on the board went to zero and then moved up to 1 when tested in revers polarity.

the bad cap jumped straight to what I believe is called infinity. and stayed there in revers polarity.

After testing with correct polarity the 2 undamaged caps jump to infinity

The one I suspect of being damaged, while in the board went to infinite and stayed there, but now that it has been removed from the board it jumps to zero and then moves up to 1k.

The results themselves were not what led me to believe I had a bad cap because I don't really know how to use a multi meter, but the fact that I got 2 caps that looked fine giving me the same result and then a cap of the same value that looked like there was stuff leaking from it giving me a different result.

The under side of the cap were the lead's protrude, the negative lead appears to be were something has leaked, but seen as you say there is nothing to leak I'm guessing this might just be were the liquid that was spilled on it has settled.