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Post by drc on Aug 27, 2012 22:18:36 GMT -5
Anyone know of a good supply source for those old Atlas Oil caps?
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Post by 2600 on Sept 2, 2012 22:02:35 GMT -5
Like looking for good, original tires for your Ford Model A.
Modern-day plastic-film capacitors are the most popular replacement for so-called "oil" capacitors. The oil is soaked into a sheet of paper that separates the two sides of the capacitor. The paper lasts a long time so long as the rubber seals on the capacitor's metal can stay sealed. But rubber ages and fails eventually humidity from the ambient air leaks in, the paper degrades and the capacitor fails.
Are you trying to restore some piece for originality? If so, you can probably find old-stock parts. But if your intent is to make an effective repair, the more-modern film type capacitors are the better bet by far.
73
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Post by drc on Sept 4, 2012 23:13:06 GMT -5
Yea, I know what you mean. This is a cap that's under the radio, so no one will ever see it. My problem is I like to try to keep things as original as possible. I may look around a bit for an original, but I have a feeling I'll have to get a new one.
We'll see......
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Post by Rumrunner on Sept 7, 2012 20:51:59 GMT -5
I've found the few I was looking for on that "EPLACE", lol. But I strongly suggest you consider 2600's advise. If you want it to look original cut whichever side is hidden on the old cap, clean it out, replace the innards with the new cap, soldering the leads to the connections. Hope this helps! '73 from the swamp - Rumrunner........
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Post by drc on Sept 12, 2012 22:35:10 GMT -5
O.k., sorry for the lame question. This is only the second time I've ever had to cut into a radio. What kind of cap do I use to replace this with? Attachments:
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Sandbagger
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Post by Sandbagger on Sept 13, 2012 6:09:42 GMT -5
O.k., sorry for the lame question. This is only the second time I've ever had to cut into a radio. What kind of cap do I use to replace this with? I use 600V mylars. They seem to work well. |
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Post by drc on Sept 13, 2012 7:39:36 GMT -5
Thanks Sandbagger. Now I just need to find a source!
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Post by cbrown on Sept 13, 2012 8:31:41 GMT -5
Try Mouser Electronics.
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Post by drc on Sept 13, 2012 8:46:28 GMT -5
Hey thanks cbrown! I've been looking online for a source and I'm gonna be late for work! I'll spend more time looking after I get home. I went looking for a cap at several local places last weekend, but no luck.
Again, thanks for pointing me to that web page... looks cool!
drc
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Sandbagger
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Post by Sandbagger on Sept 13, 2012 19:48:29 GMT -5
Hey thanks cbrown! I've been looking online for a source and I'm gonna be late for work! I'll spend more time looking after I get home. I went looking for a cap at several local places last weekend, but no luck. Again, thanks for pointing me to that web page... looks cool! drc Yea, Mouser is a great place for parts. They have a ton of stuff and their prices are reasonable. |
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Post by drc on Sept 14, 2012 8:29:40 GMT -5
Well, I found a hole-in-the-wall electronics place here in a bad part of town that actually had the cap I needed, so I got it and put it in late last night. Turned the radio on and after several minutes guess what? Another old cap blew it's wad all over the inside of the radio. Off to the store again! I hope there isn't something else wrong with the radio.....
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Post by cbrown on Sept 14, 2012 8:53:09 GMT -5
Just assume that all the old caps are bad and replace them all. It'll save you a huge headache later on.
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Post by Marc on Sept 14, 2012 9:53:03 GMT -5
Just assume that all the old caps are bad and replace them all. It'll save you a huge headache later on. Brown Has the right idea the cascade effect cam be a real drag!! |
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Post by drc on Sept 17, 2012 19:07:20 GMT -5
Just assume that all the old caps are bad and replace them all. It'll save you a huge headache later on. I'll second that! I replaced the one known bad one, and less than ten minutes later another one blew and left me with a gooey surprise. A pain to be sure, but I do enjoy learning about fixing these relics. |
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Sandbagger
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Post by Sandbagger on Sept 18, 2012 6:25:04 GMT -5
Just assume that all the old caps are bad and replace them all. It'll save you a huge headache later on. I'll second that! I replaced the one known bad one, and less than ten minutes later another one blew and left me with a gooey surprise. A pain to be sure, but I do enjoy learning about fixing these relics. When dealing with a 40+ year old radio, there are two kinds of electrolytic caps in there. Those that have failed, and those about to. I know it's tempting (and I'm guilty of it myself) to try to save a few bucks and only replace the ones that are known to go bad first, and try to "get by" with the others. This might work for a while and if you don't mind having to yank the cover off everytime the radio acts up, it's probably ok. But if you want something that is as reliable as the day it was made, then all of the parts that deteriorate should be replaced. |
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Post by bluemax on Apr 2, 2018 8:27:45 GMT -5
O.k., sorry for the lame question. This is only the second time I've ever had to cut into a radio. What kind of cap do I use to replace this with? found this on a search...don't know where to find it. But this looks like my Robyn T123b that recently introduced me to "magic smoke". After doing some reading, it appears to me that these foil caps are part of an audio circuit, and may not be absolutely necessary to the basic function of the radio. Since I have more pressing issues to attend, I would like to proceed with other repairs. Will these caps affect any transmit/ receive function or harm the radio's basic function if left defunct? please leave a trail for this posting or a message to me. BlueMax |
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Sandbagger
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Post by Sandbagger on Apr 2, 2018 16:05:57 GMT -5
O.k., sorry for the lame question. This is only the second time I've ever had to cut into a radio. What kind of cap do I use to replace this with? found this on a search...don't know where to find it. But this looks like my Robyn T123b that recently introduced me to "magic smoke". After doing some reading, it appears to me that these foil caps are part of an audio circuit, and may not be absolutely necessary to the basic function of the radio. Since I have more pressing issues to attend, I would like to proceed with other repairs. Will these caps affect any transmit/ receive function or harm the radio's basic function if left defunct? please leave a trail for this posting or a message to me. BlueMax The .1 uF electrolytics that usually pop like firecrackers in the Panasonic chassis radios are part of the -82V bias circuit. This is necessary for the squelch to function as well as providing cutoff bias to the final to keep it from oscillating while on receive. So you really can't ignore them. |
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Post by bluemax on Apr 3, 2018 8:48:17 GMT -5
OK, I know this will make some of you cringe cause it's really bogus. I'm not a very good guy to do really fine solder work in tight spaces. (I've "almost" seen the size of some of these new ceramic caps)
I have cleaned out the cartridge of the bad cap. The points that it connect to are almost invisible and VERY close to a dozen other wires and joints. I would like to leave the existing "can and cap" in place and solder the new cap to the existing leads since they are well exposed and held fairly stationary. It might not look good, but it SHOULD function. If I take all the rest of the stuff off I need to make working room, this thing will be scrap. I figure that getting it operational is more important than historic preservation. If I get it all up and running, I can then decide how beautiful it needs to be.
Thoughts?
(parts are on the way)
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Sandbagger
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Post by Sandbagger on Apr 3, 2018 21:34:39 GMT -5
OK, I know this will make some of you cringe cause it's really bogus. I'm not a very good guy to do really fine solder work in tight spaces. (I've "almost" seen the size of some of these new ceramic caps) I have cleaned out the cartridge of the bad cap. The points that it connect to are almost invisible and VERY close to a dozen other wires and joints. I would like to leave the existing "can and cap" in place and solder the new cap to the existing leads since they are well exposed and held fairly stationary. It might not look good, but it SHOULD function. If I take all the rest of the stuff off I need to make working room, this thing will be scrap. I figure that getting it operational is more important than historic preservation. If I get it all up and running, I can then decide how beautiful it needs to be. Thoughts? (parts are on the way) Well, consider me cringed... But yea, if you can make an effective repair that way and it doesn't short out to nearby parts, it should "work". |
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Post by bluemax on Apr 4, 2018 7:54:37 GMT -5
I gave this more thought last evening, and the fact that I now have two dangling halves of a former component really does raise insulation issues, and I "assume" that a short not only negates the operation of the cap, but jeopardizes other circuitry. I'll check to see if a clean cut at both end of the existing can and lid leave me some decent pigtails to attach the new parts. That might keep me far enough away from the old joints. None of the new caps I investigated had long tails, but that may not be so bad if I leave some of the old ones in place.
One last question...for now. My Dad's old Nordmende Hi Fi was in a wooden case with the standard non-polarized AC plug. No way to tell( without test meter) if the board was hot or neutral each time it was plugged in, but as long as the case was all closed you couldn't touch anything. These Robyns are metal cases with metal chassis, and I don't see any insulation between the two. But since the plug is not polarized, how is it that we don't get shocked or worse? Especially guys who work in the basement on damp concrete floors without GFI outlets!! How is this board never hot when either AC leg could be hot or neutral?
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Deleted
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Post by Deleted on Apr 4, 2018 7:58:34 GMT -5
Yea, I know what you mean. This is a cap that's under the radio, so no one will ever see it. My problem is I like to try to keep things as original as possible. I may look around a bit for an original, but I have a feeling I'll have to get a new one. We'll see...... You can restuff the original cap can with a polyester (Mylar) or polypropylene cap. You have a new cap, but the cover or can is the old cap. Google restuffing capacitors. BTW, most modern film caps are superior to any oil caps. |
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Sandbagger
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Post by Sandbagger on Apr 4, 2018 18:36:04 GMT -5
I gave this more thought last evening, and the fact that I now have two dangling halves of a former component really does raise insulation issues, and I "assume" that a short not only negates the operation of the cap, but jeopardizes other circuitry. I'll check to see if a clean cut at both end of the existing can and lid leave me some decent pigtails to attach the new parts. That might keep me far enough away from the old joints. None of the new caps I investigated had long tails, but that may not be so bad if I leave some of the old ones in place. One last question...for now. My Dad's old Nordmende Hi Fi was in a wooden case with the standard non-polarized AC plug. No way to tell( without test meter) if the board was hot or neutral each time it was plugged in, but as long as the case was all closed you couldn't touch anything. These Robyns are metal cases with metal chassis, and I don't see any insulation between the two. But since the plug is not polarized, how is it that we don't get shocked or worse? Especially guys who work in the basement on damp concrete floors without GFI outlets!! How is this board never hot when either AC leg could be hot or neutral? Old tube table radios often used "transformerless" power supplies, which pretty much grounded the line voltage neutral to the chassis, while the "hot" side used a half wave rectifier, and appropriate filter caps, and usually was able to develop 150V to power the plates of the tubes, which was plenty for a small radio. Of course, if you defeated the polarized plug, and reversed the plug's proper polarity, the chassis became "hot". Instant shock hazard.Which is also why most of those radios completely enclosed the metal chassis inside a bakelite cover, to prevent someone from making contact with the chassis. BUT, this doesn't apply to our tube CB radios. They all have transformers in them which effectively isolates the chassis from line voltage and the shock hazard that occurs. But on many radios, there is a 10 Megohm resistor from one side of the line to chassis ground. And that is enough to sometimes give you a little bite if you touch an ungrounded chassis and another grounded object. Because the resistor value is so high, the current will be very low and all you should feel is a tingle. Not enough to electrocute you. |
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Post by bluemax on Apr 5, 2018 7:35:17 GMT -5
Alright, then it sounds like with any amount of sanity and common caution, I don't need to rewire these things with three prong plugs. All my equipment is behind me when I'm near the sink, and all GFI protected; a precaution that was designed into the layout of my room.
Thanks, AGAIN. And, no, my electrical interference issue hasn't yet been corrected. I suppose the crews are too busy with winter storms. As the weather is getting warmer, the trouble is again increasing. So I'm only on the air on COLD days, or evenings after dark when the temps are down around 35 or less.
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