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Replacing CapCan Electrolytics with economic Radial lead caps

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  • Replacing CapCan Electrolytics with economic Radial lead caps

    After having replaced the three-section 200V/60-60-40uF Cap Can just recently, using a somewhat clumsy approach (that did work), cutting a copper square that I soldered first to the twist-tab ring terminals that I salvaged from the aged CapCan, then soldered the cleaned-up copper to the plated steel chassis, I didn't have any blank non-copper clad G10 or FR4 1/16" Fiberglass sheet material that I could have cut to be mounted onto the chassis.

    Having purchased the swagging tools to work with the discrete turret terminals on a recent build (Hiwatt DR201 Bass Amp clone), I had in one location on the power tube turret board, installed a pair of those turrets to allow the lead wires of the radial cap I used 220uF/450V to pass thru the thru-holes of the turrets, and added a touch of RTV on the bottom of the cap, and soldered the lead wires into place.

    Click image for larger version  Name:	Power Tube Turret Board-7.jpg Views:	0 Size:	1.60 MB ID:	967362 Click image for larger version  Name:	Power Tube Turret Board-2.jpg Views:	0 Size:	1.42 MB ID:	967364

    I have a Tektronix R5031 Dual Beam Storage Scope that probably has a bad capcan that finally shut down on me last year, and I haven't gotten back to that restoration project yet. I just checked McMaster-Carr to see what they had in G10 Fiberglass board (unclad), and perhaps FR4 (Fire Retardant version of G10). They didn't list the FR4 being available, but a 12" x 12" square of the G10 1/16" material was only a touch over $9 (plus tax/shpg).

    On this Altec 316A I had just recapped, I had selected three 68uF/200V Radial Electrolytic Nichicon UVK series caps, 13mm dia & 5mm L/S. I just checked the turret terminals, and see the base dia of these turrets are also 5mm, so I can't use them on 5mm mtg centers, but could at 7.5mm centers. (The Lead Spacing would need to comply with minimum spacing for voltage potential to prevent arc-over).

    In the example shown above, those are 10mm centers. So, that does seem like a better way of placing Radial Lead caps onto a fitted fiberglass board into the space where the cap can had been installed, and carefully placing swagged-in turrets to have solid lead mounting for solder connections. I had selected those 68uF/200V parts to potentially place them within the inside dia of the original can that was being replaced. I didn't know until later that can was a solid-filled part with the capacitor sections imbedded in the goop. The plan was to have the three caps clustered together. I hadn't yet thought about the fiberglass plate and swagged-in turret terminals. They would have fit within that ID of the can.

    Click image for larger version  Name:	Altec 316A-Recap-12.jpg Views:	0 Size:	1.26 MB ID:	967366

    I'll post the results on the next retrofit trying this method.
    Attached Files
    Logic is an organized way of going wrong with confidence

  • #2
    Neat idea using the turret board! I've seen some people use a new PCB for radial caps in old SVTs as a drop in replacement in lieu of the multi-section can. The turret board is a nice idea for when terminal strips won't work. I'll have to file this one away for later

    https://www.youtube.com/watch?v=yKNETsDAZNo

    ^ a video of Psionic Audio's drop in filter board for vintage SVTs.

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    • #3
      20 years ago, i used to sell those Mallory FP caps on eBay, don't know if people are still buying them.

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      • #4
        Originally posted by GoldtoneWorkshop View Post
        https://www.youtube.com/watch?v=yKNETsDAZNo

        ^ a video of Psionic Audio's drop in filter board for vintage SVTs.
        I've seen it, Lyle's done impressive work here. Looking forward buying some boards from him, I hope he gets 'em into circulation.

        This isn't the future I signed up for.

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