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 1931 'potted' power supply
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 Return to top of page · Post #: 16 · Written at 11:21:07 AM on 2 September 2020.
STC830's Gravatar
 Location: NSW
 Member since 10 June 2010
 Member #: 681
 Postcount: 1253

"The laminations of the transformer are not bolted together"

So the pitch would be needed to stop lamination buzz. Wonder if it is also there as interlamination insulation as well.


 
 Return to top of page · Post #: 17 · Written at 8:06:46 PM on 3 September 2020.
Brad's avatar
 Administrator
 Location: Naremburn, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 7290

Photos uploaded to Post 15.


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

 
 Return to top of page · Post #: 18 · Written at 9:17:09 PM on 3 September 2020.
Robbbert's avatar
 Location: Hill Top, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 2011

Hydra condenser - cut off one head and two more shall appear.

That black pitch is really messy, luckily it's restricted to roads now.

Those resistors etc in the heater supplies were to minimise hum. Some radios had a tiny adjustable resistor under each valve, so you could tune out the hum.


 
 Return to top of page · Post #: 19 · Written at 9:58:38 PM on 3 September 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

In the 70 series Lyric, I mounted the caps on board diagonally, avoiding the need for pitch (lined the can).

The humdingers are quite normal the ones on the OP tube are also incorporating the self bias. Probably more effective if the chassis is grounded.

One may be able to put balsa wood blocks under the laminations: Would need to see how it is arranged & Acid free Silicon (Roof & Gutter) is a wonderful GP space occupier & glue and used wisely can help air circulation & cooling. Albeit with a few things I have wrapped it with cling wrap, or stuck it in a plastic bag & pumped in some expanding foam. It does not like Acetone.

I would use new wire with the same colour code as necessary. Do note, if you can make a clean inline splice, shrink tube is your friend.

Marc


 
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