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 400uf 12vp Electrolytic Capacitor?
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 Return to top of page · Post #: 1 · Written at 2:14:35 PM on 1 April 2017.
JamieLee's avatar
 Location: Clare, SA
 Member since 27 March 2016
 Member #: 1894
 Postcount: 384

Hello my fellow Radio enthusiasts!

I re-capped my AWA Radiola 809GY Radiogram and have fitted a nice long cotton covered cord.

The Garrard RC72A Record Changer is working a treat, Although It may need an adjustment as some 78's get to the end and the changer doesn't actuate until I manually jog the "start" lever, It seems obvious not all finish in the exact same spot, some not close enough to the centre for the mechanism to trip.. Anyway, the main issue at the moment is the radio, which despite the Phono Amplifier working loud and clear, there is no offering from the radio, it is possibly a resistor high issue, which I will check, however I couldn't quite finish re-capping, as there was one humungous red monster of a Ducon, I snipped out, believing to be a filter cap, but nope! It sits between pin (K) Cathode? On V1 a X61M Valve and Chassis, in parallel with a 150 ohm half watt resistor. I had to solder it back in, because I don't have one of these, I found a 470μF one in an old computer, but that's 70μF too big.. There's one on Ebay, A Sprague, but it's 30v and mine is 400μF 12pv, so I'm at a loss as what to do as I can't find one, so wondering if the Sprague 400μF 30v one would be ok, or do I get Jaycar 100μF 16v ones and pair up 4 in parallel? Or does anybody know a source of these? Maybe I could re-form the original with a 9v battery?

Any ideas welcome. I have the pin voltage chart, so once I'm sure this cap is good, I can go over resistors and pin voltages.


 
 Return to top of page · Post #: 2 · Written at 3:24:28 PM on 1 April 2017.
Gandhn's avatar
 Location: Windella, NSW
 Member since 5 November 2010
 Member #: 770
 Postcount: 267

This cathode bypass cap is not critical as to value, the difference between 400 and 470 mfd is within tolerance at 20% anyway.The actual voltage across it will be probably 12 to 15 V, (I don't have the valve spec here), so allowing for a margin, 25V and up will be fine. If you have a 470 mfd at 25V or greater, use it.
Harold


 
 Return to top of page · Post #: 3 · Written at 11:53:45 PM on 2 April 2017.
Wa2ise's avatar
 Location: Oradell, US
 Member since 2 April 2010
 Member #: 643
 Postcount: 620

+1 The 470μF cap will work fine.


 
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