Re: Capacitor Discharge Rate Testing!

Thanks Momaka for that excellent (how to) on reforming, in my case 43 year old caps. You could well be right! I'm sure it will go on to help others out
I thought the same about the mains voltage switch, but it was on the right 230 volts. Unless it was switched over after, but I doubt it.

But I was impatient and had a look around online for replacements and they seem to be cheap enough to just not take the chance of doing further damage. And I've seen online at least 1 other person had a problem with them here [URL="http://rfscientific.eu/sites/default/files/articleextra/tektronix_485_repair.pdf"]http://rfscientific.eu/sites/default/files/articleextra/tektronix_485_repair.pdf[/URL]...

Re: Capacitor Discharge Rate Testing!

The suspect caps on these 485 scopes are the under voltage rated tantalum caps supposedly.

Re: Capacitor Discharge Rate Testing!

Haven't seen the dreaded Rifa caps in this unit yet. It is dated from 1980 though, going by an etched IC on the PCB, so it is possible I suppose. I need to get at the crt transformer board buried in the middle of the scope. But I doubt I'll find any on that board.

Re: Capacitor Discharge Rate Testing!

Haven't got that far yet. Hope that's not the problem. Visually it looks fine though. It was well packed, so survived the shipping intact. Looks like it originally came over from America to the UK, and now Ireland. Going by the original receipt that came with it.
It was last calibrated in 92 the sticker on the outside says

Re: Capacitor Discharge Rate Testing!

Yea, dunno. Maybe I'm probably better off changing them out.
Might give the reform a try first just to see if it makes a difference though.
Thanks for all the interesting advice anyway guys, much appreciated

Bought this Tektronix 485 scope on ebay, it looks like it was out of action for a long time. Needed a good clean. The units mains glass fuse was vaporized. So something is bad. Checked for shorts on the inverter pcb, but nothing really looks wrong. One thing that did look dodgy was the board connectors, some...

Hi, I have 2 identical capacitors from an old scope I'm trying to get running.

Both caps measure ok in ESR and Capacitance values imo.
Data sheet says tolerance spec is -10 +50%. And these are way under that.
Both of there original values are marked as (430uf 200vdc).
After ~40 years, they now measure 485uf and 465uf. Well under the +50% tol.

Anyway I charged them up to 24 volts dc and discharged them slowly down to 10 volts using a Digital Multi Meter. Funny thing was one of them just took over 4 minutes to discharge down to 10 volts. And the...

Re: TX-P50UT30B Dead - No Standby light.

Thanks I'll have a look tomorrow.

Hi, haven't been on the forum for a while. But I thought I'd ask here incase this has already been solved.

Anyway, I have this Panasonic TX-P50UT30B. It's completely dead, no red standby light, nothing. I took off the back and had a look at the fuses. All of them are intact. No shorts when testing the mosfets of the Power supply either.
And the capacitors look fine also.

I'm guessing it's a main board issue. But I don't really know tbh. Maybe a corrupt firmware flash, dunno.

Re: LG 26LC2R - ZJ Bulging SAMWHA caps on psu

Just to update on this,got the Nippon KY and Rubycon RX30 caps.Installed them and its up and running fine ; )

Re: LG 26LC2R - ZJ Bulging SAMWHA caps on psu

Here's the sizes of the caps if you're interested,they're no where near the sizes on the data sheet! Maybe that U4A is some kind of date code,4 meaning 2004,dunno!

SAMWHA 1000uf 35v = (12.5 x 25)

SAMWHA 1000uf 25v = (10 x 24)

Re: LG 26LC2R - ZJ Bulging SAMWHA caps on psu

Thanks for all the help guys Just measured the caps,i think im fine with 12.5 diameter max on both.Cause the test caps i put in to replace the 25v samwha were 12.5 dia.Ok after all that consideration checking around,i went with the best bang for me buck,lol.Ya,im a cheap skate Well im fixing this for someone else,so i dont want to charge them a lot,especially if it breaks down again later.I wouldn't care if it was mine.Well heres my choice,with all your help of course

[URL=http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110442637743&ru=http%3A%2F%2Fshop.ebay.com%3A80%2F%3F_from%3DR40%26_trksid%3Dp4712.m38.l1313%26_nkw%3D110442637743%26_sacat%3DSee-All-Categories%26_fvi%3D1&_rdc=1]1000uf...

Re: LG 26LC2R - ZJ Bulging SAMWHA caps on psu

Heres two not so good images of the removed caps



Btw,there was 4,but i hacked it open to have a look at it

Re: LG 26LC2R - ZJ Bulging SAMWHA caps on psu

Ya pcbonez,these are the same VA series,forgot to put that down earlier.Also
i had a look around all those sites krankshaft,but i couldn't find any Nippon Chemi-Con KY or KZM,they must be tough caps to get hold of!
What about the Panasonic FC series,does it matter if they're bi polar caps?

Re: LG 26LC2R - ZJ Bulging SAMWHA caps on psu

Just finished putting in caps i had lying around (two 1000uf 35v-one old cap other new) and (two new1000uf 16v).I know i needed two 25v caps,but i thought i'd just give it a try! powered it up and to my surprise it works now
Im not going to leave these in,this was just to test if it worked.Now im definitely going to get new caps to replace these.So wheres a good site to get these nippon chemi - con caps?

Re: LG 26LC2R - ZJ Bulging SAMWHA caps on psu

Ya,i've never seen them either until i did a bit searching for these.They're out there,but not a huge selection.Heres some 130C Rubycon series RX30 i've found,whats your thoughts on these?

[URL=http://ie.farnell.com/jsp/search/productdetail.jsp?id=8126593&Ntt=RUBYCON-35RX301000MEFG12.5X25-CAPACITOR,1000UF,35V]Rubycon RX30[/URL]Re: LG 26LC2R - ZJ Bulging SAMWHA caps on psu

Ya,i've never seen them either until i did a bit searching for these.They're out there,but not a huge selection.Heres some 130C Rubycon

Re: LG 26LC2R - ZJ Bulging SAMWHA caps on psu

Thanks japlytic ; ) Are Nippon Chemi-Con available in the same spec ie 130*C,or can i use lower values in temperature with these caps.Its the 130*C thats throwing me off a little,they're not the easiest caps to find.Btw if you could post a link for these,i'd appreciate it.

Hi,i've got this lg lcd tv that powers up,but doesn't display anything on screen.I've opened it up and found 4 SAMWHA caps bulging on the psu.Im thinking if i replace these i might get it going again,dunno.Only problem is im not sure what to replace them with! You guys are the experts here on caps,so i was hoping you could point me in the right direction.Ok,heres the stats of these 4 caps,2 of each,

SAMWHA
1000uf 35v (+-20%)
U4A PET 130*C

SAMWHA
1000uf 25v (+-20%)
U4A PET 130*C