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Author Topic: leave it in, take it out, leave it in...............  (Read 1733 times)
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wb3eii
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« on: November 30, 2014, 05:16:10 PM »

OK, here's the scenario, solid stating the power supply on the mod deck of my t-3.
I'm looking at the easy way, which is to just jump a diode at pins 4 and 6 to pin 8 at all of the 5r4wga sockets.
 I'm also looking at the harder way, which is lifting the filament wires at the socket and at the transformer. Second method will allow me to take the d.c. voltage off the filament transformer, and possibly save me some grief if the 5 volt transformer ever decides it doesn't like the high voltage running through it.
So do I leave the filament transformers in, or take them out?
Is there really a need to run my dc voltage out through the center taps?
 Solid stating this supply is really necessary, as there is a big wire wound pot at he primary of the filament transformer that has a habit of opening up, I found a new pot, I don't want try to find one again.73 Ed.
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KA2DZT
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« Reply #1 on: November 30, 2014, 05:35:15 PM »

Disconnect the filament xfmrs but leave them on the chassis.  If the dc voltage is above 400 volts you should use two 1KV piv diodes (in series) in each leg.

Fred
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steve_qix
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« Reply #2 on: November 30, 2014, 05:38:05 PM »

Yes, disconnect the transformers but might as well leave them in.

If it's a full wave center tapped type of configuration, the diodes will need to be 2.8 X the RMS voltage of the transformer (RMS voltage being 1/2 the full secondary voltage - AKA center tap to one side of the secondary).  That's the minimum.  I'd make it 4x the RMS to be safe.  Diodes are real cheap these days. 

Regards,  Steve
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