[Boatanchors] Capacitor for Hallicrafters SX19R

[Bruce Long]

Hi David:
Sounds like a multi-section power supply electrolytic capacitor.  This should not be too hard to replace nor should it be sensitive at all to exact capacitance value nor are the voltage rating critical assuming the voltage rating of the replacement cap is sufficient.

First off do you have a schematic for the radio?  If so how about scanning it and sending it as an attachment ( if the list server permits that).  That way we can exactly identify the component and decide what is needed to replace it.

If indeed I am correct in assuming this is a multisection capacitor, you have essentially zero likelihood of replacing it with  a new part.   And if you are extremely likely to find an exact equivalent NOS ( New old Stock) part it is certain to be bad as well.   These type and vintage capacitors do not age well.   Failure rate after several decades is just about 100% - doesn't matter if they where used or sat unused as a replacement part.

So what you need to do is to replace this capacitor with 4 (?) separate capacitors.
For the 20 uF/350 vdc, the 80 uF/350 vdc and the 100 uF/50 vdc, all you have to do is to replace these with modern new capacitors having the same or somewhat greater capacitance and the same or greater voltage rating.

For the four capacitor for which you cannot read the value, let us have a look at a good schematic.  The value and voltage rating is almost certainly  recorded there.   If not we can deduce a reasonable value and voltage rating from its location on the schematic and its function in the radio.

I assume this sprauge capacitor is in a metal can and has 4 leads out the bottom?  Please correct me if  wrong  I am wrong.

If you can send me a schematic I will help you locate suitable replacements.  I might even have what you need in my junk box.

Some collectors who wish to preserve a particularly rare or valuable receiver in original condition will carefully open up the alum cap, remove the contents and clean out the can, then place the modern replacement caps inside the can.  This usually works out as modern caps are on the whole significantly smaller than vintage caps.  Google Capacitor stuffing for more details


good luck

Bruce  KJ3Z








________________________________
 From: DAVID <dnapier at bellsouth.net>
To: Boatanchors at puck.nether.net 
Sent: Friday, April 20, 2012 1:02 PM
Subject: [Boatanchors] Capacitor for Hallicrafters SX19R
 
Hello to everyone!,I've never posted anything here to this point,but have
always read the posts that others have made,But now I hope to get some
help!! I'm in the process of trying to restore a Hallicrafters SX19R
receiver,replacing all the paper caps and resisters that need raplacing,I've
come to the Alum Capacitor that is mounted inside the cabinet it is a
"Sprague model number 6943J with these values on the label-" first value is
unreadable,the others are as follows,20MFD AT 350VDC-80MFD AT 150VDC AND
100MFD AT 50VDC," I Have looked high and low for this Capacitor,even for a
replacement.to no avail!! This being first time I ever tried restoring a
receiver,has been no help either!! I was wondering if somebody on this list
could help me,point me in the right direction,suggest a replacement or
whatever!! Any and all help is deeply appreciated!! Sincerely David/Ka4zuc

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