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Hints, Tips and Solutions (Do NOT post requests for help here) If you have any useful general hints and tips for vintage technology repair and restoration, please share them here. PLEASE DO NOT POST REQUESTS FOR HELP HERE! |
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24th Oct 2009, 9:44 pm | #21 |
Dekatron
Join Date: Sep 2006
Location: Kilmarnock, Ayrshire, UK.
Posts: 5,422
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Re: Electrolytic Taxidermy
Hi
Most collectors don't run their sets for long periods so restuffed caps should be reliable. The example I gave was a radio that is used every day at work and is often left on overnight or even at weekends. I usually use 105 degree caps and avoid ones with obscure names, Panasonic were good but even their quality has dropped since being made in China.# Cheers Trevor
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Cheers, Trevor. MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member |
28th Oct 2009, 1:24 pm | #22 |
Heptode
Join Date: Mar 2009
Location: Fenay Bridge, Huddersfield. UK.
Posts: 673
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Re: Electrolytic Taxidermy
Hi, for members unfamiliar with pipe cutters or wonder what they are I hope this is of use. These are two of mine and their use is to cut copper tube in plumbing. A larger size is needed for electrolytic caps and as an example a 12.7 - 44mm should be ample. These pipe cutters are readily available and with a quick web search I found; http://www.plumbworld.co.uk/pipe-cutters-616-0000 advertising this size at £12.47. Cheaper ones can be bought. They are extremely simple tools to use; the jaws are opened; the capacitor is inserted aligning the cutting wheel at the desired place and the jaws are gently closed to just nip the cap; holding the cap in one hand the pipe cutter is rotated with the other hand, by rotating and applying pressure bit by bit the cut is completed. Applying too much pressure will deform the cap so steady does it. Col..
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2nd Nov 2009, 7:35 pm | #23 | |
Dekatron
Join Date: Sep 2007
Location: Oxfordshire, UK.
Posts: 4,311
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Re: Electrolytic Taxidermy
Quote:
Unfortunately I can't tell how long this cap worked for, but clearly the people who made it thought that this was a "sound" thing to do. On the other hand this is a low value capacitor, so presumably subject to relatively low ripple current, and I note that the whole thing is only rated to 60 C. Maybe they were covering themselves . As you can see, this is a screw-terminal capacitor so I don't have the option of pipe-cutting it and hiding the trauma with a clip. I've therefore fairly carefully "unpeened" the bottom end and removed the bakelite terminal and the internals that way. Whether I can get away with re-peening (?) it remains to be seen, but at least with this design the peened surface is pulled hard down to the chassis and will be hidden. Cheers, GJ |
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10th Nov 2009, 3:46 am | #24 | |
Retired Dormant Member
Join Date: Feb 2008
Location: Auckland, New Zealand
Posts: 631
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Re: Electrolytic Taxidermy
Quote:
I do wonder a bit about the wisdom (and value) of capacitor stuffing, especially since the under-chassis is not likely to be revisited very often. Very few radios that have seen normal service have all original parts anyway and most repairs have seen replacement parts from the stock shelf, not the manufacturer. Subsequent owners of restored equipment are very likely to assume that the old caps are just that and replace them again. Pasting a note inside the cabinet or on the inside of the back advising that they have been restuffed might be a good move. Cheers Billy |
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10th Nov 2009, 11:33 am | #25 | |
Heptode
Join Date: Mar 2008
Location: Camberley, Surrey, UK.
Posts: 805
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Re: Electrolytic Taxidermy
Quote:
Brian. |
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10th Nov 2009, 4:16 pm | #26 |
Dekatron
Join Date: Sep 2007
Location: Oxfordshire, UK.
Posts: 4,311
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Re: Electrolytic Taxidermy
Given how much space was wasted inside the can I also think it's quite funny that in their adverts (see the attached one from a 1955 Practical Wireless) TCC made a big deal of how much space this design could save. Of course they did need to find some way of keeping people's fingers away from the second electrolytic, whose can is at half the HT voltage. So I guess they had little choice. And I'm sure they were right when they said that the result would be smaller than a similarly rated paper-in-oil unit.
I'll be re-stuffing mine with modern plastic-cased polypropylene motor-run caps. They're "only" rated at 475V AC (3000 hrs) which corresponds to 670V DC. But that's plenty for my application and they shouldn't be nearly as lossy or degrade nearly as quickly as electrolytics. Cheers, GJ |