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Post by elorens on May 28, 2020 19:28:46 GMT 12
I’m thinking about re-stuffing this electrolytic on my 1938 Courtenay model 85. Is there a tutorial on this process anywhere? Presumably I begin by prising off the top? But how to make the connections? Tips welcome! Thanks Lawrence — Attachments:
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Post by Philconut on May 28, 2020 21:47:22 GMT 12
Hi Lawrence. If you prize the cap off you have to be sure that you can replace it to your satisfaction. Doing the job this way also presents problems for connecting the new cap. I have taken to cutting the can into two about 30mm from the bottom. Mark across the cut with a felt pen so that you can reunite the two pieces later. Carefully remove the perforated wrap for later use. Remove all the old internals and cut the centre electrode off about 10mm above the remaining can. It's a good idea to check the insulation between the electrode & can before you go any further. Drill a 3mm hole in the centre electrode. Also drill a 3mm hole in the base and countersink it. Fit a 3mm countersunk head screw here and using a piece of hookup wire connect the negative of the new cap using a washer & nut. The screw head should be flush with the can bottom. Attach the positive lead in a similar way but use a round head screw. Replace the perforated wrap in the bottom piece. Three quarters fill the top piece with melted paraffin wax, insert the inverted bottom piece into it. Align the pen mark, bind the joint with masking tape and turn the can upright. When the wax has cooled remove the tape. If you have made a good job of the cut it shouldn't be too visible. There is always the option of making a paper label and wrapping it around the can. The solidified wax, the perforated wrap and the centre electrode will give sufficient strength to the whole unit as there is no mechanical load on it at all. Job done!
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Post by elorens on May 28, 2020 22:36:28 GMT 12
Hi Lawrence. If you prize the cap off you have to be sure that you can replace it to your satisfaction. Doing the job this way also presents problems for connecting the new cap. I have taken to cutting the can into two about 30mm from the bottom. Mark across the cut with a felt pen so that you can reunite the two pieces later. Carefully remove the perforated wrap for later use. Remove all the old internals and cut the centre electrode off about 10mm above the remaining can. It's a good idea to check the insulation between the electrode & can before you go any further. Drill a 3mm hole in the centre electrode. Also drill a 3mm hole in the base and countersink it. Fit a 3mm countersunk head screw here and using a piece of hookup wire connect the negative of the new cap using a washer & nut. The screw head should be flush with the can bottom. Attach the positive lead in a similar way but use a round head screw. Replace the perforated wrap in the bottom piece. Three quarters fill the top piece with melted paraffin wax, insert the inverted bottom piece into it. Align the pen mark, bind the joint with masking tape and turn the can upright. When the wax has cooled remove the tape. If you have made a good job of the cut it shouldn't be too visible. There is always the option of making a paper label and wrapping it around the can. The solidified wax, the perforated wrap and the centre electrode will give sufficient strength to the whole unit as there is no mechanical load on it at all. Job done! Great, thanks very much for this! Do you use a fine hacksaw to make the cut? cheers Lawrence —
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Post by Philconut on May 29, 2020 20:56:18 GMT 12
Yes and a fine file to tidy the edges.
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6A8G.
Society Members
Hard working kiwi soundmixer.
Posts: 69
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Post by 6A8G. on May 30, 2020 9:51:48 GMT 12
A long while ago I saw a post on Youtube about this - sorry I can't remember who it was but he was American. It very fiddly & you use a small screwdriver to gently & patiently prise the lip of metal which is part of the side where it crimps to the underside of the cap. Work slowly around the perimeter until the terminal board is free. Next, put it in a very hot oven or blast it with a painters heat gun. After a while it should be possible to pull the guts out cleanly. Get rid of everything except the contacts & terminal board. Beware, sometimes the internal terminals are aluminium. Drill through from the inside to the underside so you can pop the leads through & terminate them onto the existing underside terminals. (Damn! I wish I'd bookmarked the more interesting radio stuff). On a different tack, check out David Tipton's channel on Youtube. He's Australian (Queensland), self-taught, & very very clever.
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