[Milsurplus] GO-9, AT-12 - fil choke

[WA5CAB at cs.com]

OK, but several other things need to be mentioned that haven't yet.  First, 
you need to connect the replacement chokes to the four points where the 
original was connected.  The 837 VFO filament is shunted by two 40 ohm 1 watt 
resistors in series.  These up the nominal filament current to the VFO to 826 
mA.  The cathode is tied to the junction of these resistors and to some 
capacitors.  The center-tap of the filament supply winding on T-202 goes to 
ground through a 1000 ohm 20 watt resistor, which is the cathode resistor for 
the VFO.  If you use a 12.6 volt outboard filament transformer, you need to 
include the latter resistor.  I don't know just what effect simply grounding 
the center-tap of the 12 volt winding would have but it isn't likely to be 
beneficial.  And finally, you would need to bypass the 4.5 ohm IPA filament 
resistor.

In a message dated 6/4/2009 10:40:19 AM Central Daylight Time, 
cosmoline at aa4rm.ba-watch.org writes: 
> Hey men.  Get a red-mix T-150 toroid fm Palomar &wind it with small 
> speaker
> wire for the 12.6v delivery for the two 837s.  Let original chokes dangle
> inside
> 
> No v-drop@ 1.4A  with toroid thing
> 
> 

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480