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 Ducon polyester capacitors
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 Return to top of page · Post #: 1 · Written at 8:24:09 PM on 9 March 2016.
Samt's Gravatar
 Location: Hobart, TAS
 Member since 6 May 2013
 Member #: 1337
 Postcount: 73

Hi, I'm currently restoring a 1962 Rock-Ola jukebox. It was made in Australia by Goddard Novelty Co and it has an Australian built valve amplifier. I have replaced the selenium full wave rectifier with a silicon bridge rectifier and I have also replaced the electrolytic capacitors. The remaining capacitors in the amplifier are blue Ducon polyester capacitors.
How reliable are the Ducon polyester capacitors? They still test with the correct value on my capacitance meter, however I'm not sure due to their age if they will fail under high voltage.
Thankyou, Sam


 
 Return to top of page · Post #: 2 · Written at 9:20:34 PM on 9 March 2016.
Robbbert's avatar
 Location: Hill Top, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 2011

If they look alright, they probably are ok.

I leave selenium rectifiers in unless they have failed. Sometimes they can give off an awful stink when failing.

Do you have photos? What valves does it have?


 
 Return to top of page · Post #: 3 · Written at 9:26:40 PM on 9 March 2016.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6678

If you are referring to the clear Styroseal type, I have found them to be pretty good, other than a couple that had cracked open.


 
 Return to top of page · Post #: 4 · Written at 9:57:53 PM on 9 March 2016.
MonochromeTV's avatar
 Location: Melbourne, VIC
 Member since 20 September 2011
 Member #: 1009
 Postcount: 1179

I know the type you are referring to.

They are a bluish/green tubular axial capacitor, the same dimensions of the earlier wax paper types, that were around in the 1960's. I have a restored Kriesler 11-99 with them in untouched.

I believe they are reliable and would leave them alone.


 
 Return to top of page · Post #: 5 · Written at 11:06:32 PM on 9 March 2016.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

Polyester, is good, Styroseal's don't like a lot of soldering heat.

Waxed paper, oil filled tubular axial, old electrolyics and anything with "Micamold" on it are the caps that cause big problems.

American Mica caps can be bad news, but ours don't fail that often (That does not mean not at all)


 
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