Filter cap selection

[John M Iverson]

A-K 55   there is a "quality" cap in the output tx can, this is the one
on the right  looking from the front. these short out and you will get
little audio or none.  it is hard to measure as it is acros the p-p
winding.  All of those have been easy to fix.  take the top off the can
and see if you can see a lead in the tar. now comes the fun--- you have
to very carefully pick the tar off the lead and verify that it goes to
the cap and not the tx. when you are sure it is the cap lead, cut it.
then check the reistance plate to plate of the output tubes, if you did
it right  there will be continuity.  the new cap will mount under the
chassis  soldered plate to plate of the 45s. I have many of the filters
that you need, I bought a lrge quanity of speaker cross over caps that
were rejected as being out of cap tolerance,  the 55s love'em.  happy
holidays    jack
Jack Iverson    K0EWU    jackiv at juno.com

On Fri, 1 Jan 1999 12:35:54 PST Gary Pewitt <gpewitt at EXECPC.COM> writes:
>Gang, while looking through the DigiKey catalog for caps
>to use in repairing a couple of old receivers for a friend
>(Atwater Kent 55C and Philco 40-180) I saw most of the caps
>were rated for DC working voltage.  Since I don't know the
>voltage ratings on the original caps I just picked 400v caps
>as close to the original capacity rating as possible.  Usually
>a bit higher if I couldn't get the exact value.  What concerns
>me is the power supply filter caps.  The AK does not seem to
>use electrolytic caps, at least there is nothing to indicate
>that it does in the Ryder sheets.  I've seen references on
>the list about ratings for AC.  Do the power supply caps
>(2.0, 2.3, and 2.3 mfd) need to be selected for AC handling?
>I had picked out some Panasonic E series metalized polyester
>caps at 2.2 mfd and 400v for all three.  I didn't see any
>orange drops in the catalog.  Should I use something else?
>I had bought a spare AK chassis for parts and it had the
>main power transformer melted down (tar all under the chassis)
>but the filter capacitor can's wiring did not seem to have
>overheated while the filter choke can's wiring had.  I never heard
>of a shorted choke doing this sort of thing.
>I am going to add a fuse near the power switch, should I try to
>fuse anything else?  Enlighten me please, it's been a -long-
>time since tech school at Keesler.
>Thanks  and 73  Gary   gpewitt at execpc.com
>
>-------------------------------------
>Name: Gary Pewitt N9ZSV/KT
>      6120 W. Calumet Rd. Apt 204
>      Milwaukee, WI  53223
>      414 355 8147 Home 414 297 4307 Work
>E-mail: gpewitt at execpc.com
>Date: 01/01/99
>Time: 12:35:54
>
>
>----------------------------------
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