[captainslack]

I've started restoring the 48-1256 I got last month.  Was making an inventory of capacitors that needed replacing when I noticed the one in the center of this pic:


[Image: http://i.imgur.com/juiKNdgl.jpg]

I'm still learning when it comes to electronics and I've never seen a capacitor with a wire wrapping before.  According to the documentation I've gotten (thanks Squire!), it's a .2uf 400v cap used for line isolation and says to wind the same number of turns around the replacement.  The Service Bulletin describes it as "condenser and choke assembly resonate at 455kc."  

What's this cap for and why the wire wrapping?  What's the best route for me to go in replacing it?  I'm pretty sure the new one is going to be a lot smaller and I'm pretty sure it's not going easy to replace the wrapping.

[Squire]

Glad I could help you out! I've been informed that these wrapped caps were used to filter out interference from a maritime broadcast band that is no longer in use. Just replace it with a normal modern .2 cap and all should be well. I did just that when I restored a "Hippo" and just recently in my 46-1203 with good results! I can't speak for my 48-1256 because it's decided to give me trouble! I've gone through the caps and resistors and have the amp working but I get no radio, just a hum. Probably time to start my own thread and ask for help!

[captainslack]

I replaced the power cord & the 50X6 on mine. Got the tubes to light finally, but I'm only getting hum as well. Hopefully new caps will fix whatever is going on with mine.

[Radioroslyn]

So your the other collector in Clayton. I've got some kin in Chapel Hill and Mebane. The hum will probably go away when you replace the filter condensers C-101 102 and 103. Polarity is important the 50X6 tube is use as a voltage doubler. Most AC/DC sets use a half wave rectifier and only develop about 120vdc for the high voltage. Your set is not truly an AC/DC set as the voltage doubler requires AC for it to double the DC output. It will develop about 225vdc so it is also important that your replacement condenser are rated at 250v or better. It also sports an AC motor the the turntable.

Terry N3GTE

[mikethedruid]

Captain, when I encountered this situation on the 48-482 I restored, I just used a modern 600V yellow poly cap of the right value, wrapped it with some paper with white glue on it until it was just about the same diameter as the original cap, and then wound the inductive winding on that. Look at how the wire was wrapped and begun and ended on the original cap, as well as the number of turns, and try to replicate it. It is fairly easy, and not rocket science critical. Have fun, and good luck !

[Eliot Ness]

If you want to keep the original appearance you could re-stuff that original capacitor tube with a modern capacitor and reuse the same wire for the winding.  In fact, if you're careful you could possibly melt out the old cap without disturbing the inductive winding on the outside.  I think those combination capacitor/inductors are pretty cool looking and not extremely common.

On-the-other-hand, as Squire said, it would probably work fine eliminating it entirely and just using a modern capacitor by itself. 

Some like to restuff, some others don’t, and for some it depends on the set they’re working on.  In fact, Kirk started a whole thread about the subject a short time back:

http://www.philcoradio.com/phorum/showth...?tid=12943

[captainslack]

Terry: Thanks for the tips! I'll make doubly sure to get a cap of the correct voltage when I start working on this thing.

John: I probably will just take Squire's advice and not bother with the wrapping. One less thing to worry about! ;)