[Heathkit] SB 220 transformer substitution

[Carl]

It requires a DPDT switch to select the primary taps of the 2 windings. 
Each winding has 3 connections, a common and 2 options. I dont understand 
the problem?  Perhaps if you redraw the circuit to understand better.

Carl
KM1H


----- Original Message ----- 
From: "John King" <k5pgw at yahoo.com>
To: <heathkit at mailman.qth.net>
Sent: Monday, December 21, 2009 8:23 AM
Subject: [Heathkit] SB 220 transformer substitution


>
> The power transformer went bad in my SB 220 that I have now owned since 
> new and is now 35 years old. Been a GREAT amplifier!!
>
> I
> have an outboard Drake L4B power transformer on it that I put on it
> about 10 years ago.  The way the outboard transformer is connected only
> gives me 1900 volts in the SSB position. If I remember correctly, I
> just taped up the leads from the CW/tune switch and did not connect
> them to the L4B transformer.
>
> Since my L4B has a CW/tune switch
> and a SSB switch, I  would like to use the SB 220 that way and get 2700
> vdc on SSB and the 1900 vdc on CW/tune. The schematic of the Drake L4B
> isn't clear to me what transformer connections would provide both
> voltages to the SB 220. Has anyone on the list done this outboard
> transformer swap? If so, can you tell me the manner in which you
> connected to get the two voltages? The benefit of your experience and
> knowledge will be greatly appreciated. Thanks and 73, John, K5PGW
>
>
>
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