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 Mica caps for the IF cans.
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 Return to top of page · Post #: 16 · Written at 12:32:24 PM on 18 January 2016.
Brad's avatar
 Brad
 Administrator
 Location: Naremburn, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 7395

All fixed this morning. Tongue


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 17 · Written at 5:17:17 AM on 22 January 2016.
Wa2ise's avatar
 Wa2ise
 Location: Oradell, US
 Member since 2 April 2010
 Member #: 643
 Postcount: 831

Most American radios used IF transformers like these

A common failure of these are leakage paths that form on the mica wafer used to create the capacitors

More details halfway down my page http://www.wa2ise.com/radios/repair.htm
 
 Return to top of page · Post #: 18 · Written at 10:17:10 AM on 22 January 2016.
Marcc's avatar
 Marcc
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5389

What is to be realised is that American Mica caps suffered a lot from Silver migration and were nowhere as reliable as the ones here. I have never replaced an Australian IF transformer cap for anything other than breakage in 50 years.

"Micamold" anything is another US brand to watch. Most caps are not Mica as implied and there reliability is on par with the worst Wax paper & oil filled types.

Marc
 
 Return to top of page · Post #: 19 · Written at 8:52:47 PM on 22 January 2016.
Gandhn's Gravatar
 Gandhn
 Location: Cameron Park, NSW
 Member since 5 November 2010
 Member #: 770
 Postcount: 409

I am with Marcc in that I have never had to replace a capacitor in an IF transformer. Maybe I have been lucky, but they are never stressed, with only a few volts across them at most.
Harold
 
 Return to top of page · Post #: 20 · Written at 10:55:03 PM on 22 January 2016.
Tallar Carl's avatar
 Tallar Carl
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 2174

Yes I am beginning to think that the problem is a valve in the radio section going off as it heats up.
 
 Return to top of page · Post #: 21 · Written at 2:27:28 AM on 23 January 2016.
Wa2ise's avatar
 Wa2ise
 Location: Oradell, US
 Member since 2 April 2010
 Member #: 643
 Postcount: 831

Here's a mica wafer set of caps with the leakage path:

You can get thunderstorms of noise with these leakages.
 
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