I recently picked up a model 90 cathedral. Original finish and clean except for bypassed electrolytics and 3 older caps on Bakelite blocks. It needed new tuning capacitor bushings which I replaced this past weekend.
Is there a risk of playing it too much without a full re-cap? I've read a number of differing opinions from, play it till something goes wrong and then fix the issue, to recap the entire set from the beginning. I'm planning to re-stuff the original cans along with the Bakelite blocks this summer. It plays well now but I haven't played it much.
Hi Paul,
I probably wouldn't play it. It looks like three of the blocks have been bypasses w/those orange foil/paper caps (1940's or 50's) and the electrolytic caps are from the 1980's.
For me the recap isn't very time consuming maybe a hour or hour and a half once I have all the parts and tools at the ready.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
I'd say, restuff the backelites - it's not hard, and reserve the tubulars for future projects where you need some caps to look naturally.
Or if you choose not to restuff (it's not very dirty job but could be somewhat dirty if you do it for the first time and have not read how other folks learned to not get dirty - there is a thread here about that) - bite off the wires coming from inside of them to the lugs and then use them as solder posts to place new tubular caps over. Don't simply parallel the new caps to old.
The tin can caps are easy to do, but again - if you choose the easy path, you could just use new ones and cut off the old ones.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
(This post was last modified: 03-28-2018, 07:13 AM by morzh.)
I would say that it depends on how the original capacitors were bypassed, and also what circuit they are in. If they simply connected to new capacitors across the old, and left the old ones in circuit then I would not play it as it is. Replacement caps from the 80's are probably new enough not to be a problem in and of themselves, but if they were smart with the electrolytic filter caps then they would have disconnected everything from the old positive terminals and left only the negative, or can side, connected. You can use the negative side of the cans as tie points for the new filter caps but you should never connect the new filters across the old. The molded paper caps, well they might be somewhat functional, some of the Solar brand ones will still work, but they are living on borrowed time, I think that they may be coupling caps and the bypass caps are the ones in the tin boxes, but if they are bypass caps between B+ and ground I would not trust them. The ones in the tin boxes are really easy to restuff, I think they are lined with paper so you don't even have to melt out any tar, just pull them open.
Regards
Arran
(This post was last modified: 03-28-2018, 11:36 PM by Arran.)
I actually enjoy re-stuffing bakelite blocks. Have a small vice bolted to the front of my bench and some handy tools for the job. Same with the wax caps. Funny you mention that Mike. I've got a drawer of re-stuffed caps. They clean up nicely when heated and look almost new when done. I'm not one to bypass anything in this hobby.
I was also surprised at how clean it was Terry. The collector I bought it from is downsizing and only had his sets repaired to working condition, not a full recap.
I've read a few posts where some have cut the terminals off the bottom of the e-caps, leaving the original connections in tack, and use it as a tie point for replacements. Thoughts?
Thanks all for your valuable input. It's very much appreciated.
Paul
>>cut the terminals off the bottom of the e-caps, leaving the original connections intact, and use it as a tie point for replacements.
Not sure how it is: if you cut the terminals, there's nothing to solder to anymore. If you keep it, well, then you are paralleling good cap to bad.
To me the single way to use the electrolytic cap as tie point is to gut it.
But if you gutted, meaning cut it, gut it, glue it together - then why not re-stuff it?
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
You could also solder in a short terminal strip to the positive terminal under each electrolytic, one with three terminals with the center one being the one with the bracket used to attach the strip to a chassis. But if this model 90 has the original Mershon or Sprague cap cans still in place I would restuff them.
Regards
Arran
I restuff the Bakelite capacitors on every Philco that I restore. It's not hard, and is less work than installing terminal strips in their place; modern capacitors are small enough to fit inside. Watch out for the occasional Bakelite cap that has two inside, or one cap and a resistor. The tone control capacitors can also easily be rebuilt.
