[Swan] Swan 1200Z bias circuit

[Bob Letts]

Hi Dan Did u get any info the bias for 1200z? I have a 1200x with 8950s and
had to do a little repair on the bias circuit. Hope u made out ok.
Bob VE7RRL
----- Original Message ----- 
From: "K2VY" <dan at k2vy.net>
To: <swan at mailman.qth.net>
Sent: February 22, 2005 10:37 AM
Subject: [Swan] Swan 1200Z bias circuit


> Hello fellow Swan fans,
>
> I have searched the entire archive for threads relating to the 1200Z
> amplifier and only found info about the 1200X. Since nothing was found,
> I am posting the following:
>
> Swan model number:  1200Z
> Swan serial number:  156
> Tubes:  6MJ6 (x4)
>
> Question about the bias circuit:
>
> The schematic shows R19 (5K pot), R22 (3.3K, 2W) and R23 (1K, 2W) as the
> bias circuit. This is what is presently in my amplifier, which agrees
> with the schematic. My manual, which I believe is original, shows the
> same parts in the parts list, but the bottom view of the chassis shows
> R19, R20, CR11 and Q1. However, the parts list also includes CR11
> (1N4005) and Q1 (MJE521), but does not include R20. R20, CR11 and Q1 do
> not show up anywhere on the schematic.
>
> Does anyone know what the "correct" bias circuit is?
>
> Thank you very much for your help and 73.
>
> Dan, K2VY
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