Old liquid leakage capacitor - Page 1
Forum section: electronics / repair

author: gtr
author_rank: Contributor
timestamp: January 01, 2020, 10:58:41 pm
content: Hello everybodyThe manual herehttp://pacifictv.ca/schematics/eico460manual.pdfpage 15 and correction herehttp://pacifictv.ca/schematics/eico460addendum.pdfOn the photo the 2 paper capacitors C25 and C26 which are also waxed, there is a liquid between the two which flows and that left a drop in the bottom of the case. It looks a bit like varnish, it's translucent yellow, a little thick, odorless and a little oily. Is it the wax that melts? Yet it does not harden and I do not see any cracks or anything abnormal from the outside. I have desoldered a pin of each capacitor to check their capacitance and it's ok on that side, C25 = 0.09934µf and C26 = 0.1107µf. These are .1µf-1600v.On the other hand the capacitor C28, according to the manual should be a 50µf-50v and that which is there is a 250µf, 35v, -20°+70°C. Is that causing a problem because I thought I would change it to a 47µf, 50v, 85°C.Thank you and happy new year! :-)

author: andy3055
author_rank: Super Contributor
timestamp: January 02, 2020, 04:13:14 am
content: All the 3 paper caps should be replaced as they are old and must be leaking the oil used in them due to heat and old age. They will run dry and short out soon. As for C 28, it looks like someone replaced it some time with what was on hand. Get the correct values for all of them as in the manual.

author: james_s
author_rank: Super Contributor
timestamp: January 02, 2020, 07:08:51 am
content: Worse than that, they absorb moisture. This makes them (electrically) leaky and causes the capacitance to drift way out of spec. I always change those waxed paper capacitors in old gear, sometimes I re-stuff them by heating them to melt the wax and pushing out the old guts then slipping a modern film capacitor inside.

author: gtr
author_rank: Contributor
timestamp: January 02, 2020, 04:41:56 pm
content: Thank you so much andy3055 and james_s!So I'm going to replace them but I'm from Canada and I can't find a place to order this kind of capacitor. I was even suggested to replace the 0.1uf 1600V for 2000V. It would be better?Thank you! :-)

author: andy3055
author_rank: Super Contributor
timestamp: January 02, 2020, 05:46:36 pm
content: Higher working voltage (WV) is better as long as you have the space. Try Mouser/Digikey/Jameco/Newark etc.See this:https://www.mouser.com/ProductDetail/Vishay-Roederstein/MKP1839410134HQ?qs=sGAEpiMZZMv1cc3ydrPrF9JX2l62Mr4r2zRwGrAdkFE%3DSince these suppliers charge shipping, you will be better off making a full list of parts and check availability at each site so that you can order all at one go.

author: james_s
author_rank: Super Contributor
timestamp: January 02, 2020, 07:12:23 pm
content: Try Antique Electronic Supply as well, they specialize in parts for vacuum tube equipment and last I checked had a good selection of high voltage capacitors.

author: floobydust
author_rank: Super Contributor
timestamp: January 02, 2020, 07:52:51 pm
content: Just Radiosis excellent for sourcing replacement vintage parts, especially capacitors. They have big axial electrolytics and 1.6kV film caps. They're in Canada but ship internationally. A small shop, I've ordered from them before and it made the restoration easier with parts that have long leads or fit.

author: gtr
author_rank: Contributor
timestamp: January 02, 2020, 09:23:34 pm
content: Thank you all for your help.I thought I had to replace the paper capacitors with electrolytic capacitors and that's why I had trouble finding them. I think I'll buy them herehttps://fr.aliexpress.com/item/32848166111.html?spm=a2g0w.search0302.3.1.6d5d6988OxNSXc&ws_ab_test=searchweb0_0,searchweb201602_0,searchweb201603_0,ppcSwitch_0&algo_pvid=2fec8e98-ad00-437d-91c0-2c6b36280456&algo_expid=2fec8e98-ad00-437d-91c0-2c6b36280456-0I found this videothat shows exactly what is going on with my condos. It's not as much of an exaggeration in my case but it's the same thing.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 02, 2020, 10:18:17 pm
content: Where exactly are you? I see you linked to the french site, that makes Quebec more likely!

author: gtr
author_rank: Contributor
timestamp: January 02, 2020, 10:21:12 pm
content: Yes I am in Quebec.

author: floobydust
author_rank: Super Contributor
timestamp: January 02, 2020, 11:42:33 pm
content: Solenin Quebec has boutique high voltage capacitors, more for audiophools and a bit pricey, but they also have some inexpensive lines.

author: gtr
author_rank: Contributor
timestamp: January 03, 2020, 12:36:45 am
content: Thank you for the link! It is true that they are expensive!

author: vk6zgo
author_rank: Super Contributor
timestamp: January 03, 2020, 12:59:42 am
content: Quote from: gtr on January 01, 2020, 10:58:41 pmThey are "Waxed Paper capacitors" The stuff which looks a little oily is the wax.It tends to break down chemically over a long time, with heat & other environmental conditions.A brand new capacitor of this type will look a lot more "waxy" on the outside, but old ones have often lost a lot of that surplus wax, leaving the "wax-like" deposit on the bottom of the case.They arenot"oil" capacitors, which are a different breed of beast, altogether.They are replaceable by Polyester, or Polycarbonate capacitors, or probably several other types.The voltage rating will be the problem, as not so many high voltage caps are made these days.A component of the same capacitance with an equal or better voltage rating should be OK.

author: gtr
author_rank: Contributor
timestamp: January 03, 2020, 01:13:47 am
content: Thank you for this information!As mentioned above, I thought to replace them with these capacitorshttps://fr.aliexpress.com/item/32848166111.html?spm=a2g0w.search0302.3.1.6d5d6988OxNSXc&ws_ab_test=searchweb0_0,searchweb201602_0,searchweb201603_0,ppcSwitch_0&algo_pvid=2fec8e98-ad00-437d-91c0-2c6b36280456&algo_expid=2fec8e98-ad00-437d-91c0-2c6b36280456-00.1uf 2000V.

author: tautech
author_rank: Super Contributor
timestamp: January 03, 2020, 08:07:25 am
content: When looking for something a bit unusual I always try Tedss:https://www.tedss.com/Capacitors

author: vk6zgo
author_rank: Super Contributor
timestamp: January 03, 2020, 01:59:23 pm
content: Quote from: gtr on January 03, 2020, 01:13:47 amThey look OK -----most of the "plastic" dielectric caps would do the job as well, or better than the "waxed paper " ones ever did.One "plastic" type which I would shy away from arePolystyrene.They are excellent at low capacitance values, but "highish" values seem to use a different construction which looks quite inductive.Luckily, higher values of this type are rare, these days.That was not always the case, though.Many years ago, at my work, we replaced a defunct 0.47uF "metalmite" capacitor in a video amplifier stage with the same value Polystyrene.The capacitance & stray inductance formed a nice "notch" filter right in the middle of the amplifier's passband.We had to "regress in technology" & use a "waxed paper" cap, which was still "hanging in there" 20 plus years later!

author: gtr
author_rank: Contributor
timestamp: January 03, 2020, 07:36:53 pm
content: Thank you for the link tautech and thank you for this information vk6zgo, I take note!

author: gtr
author_rank: Contributor
timestamp: January 03, 2020, 11:58:11 pm
content: I replace the 0.25uf 400V paper capacitor with 0.22uf or 0.33uf because they don't have 0.25uf here.Thank you!