[Hallicrafters] Solid Stating an HT-37

[Glen Zook]

I would still remove both connections from the power transformer (5.0 VAC connections).  Remember that either filament pin can be used for the B+ output and there was no standard as to whether or not it was pin 2 or pin 8 on the rectifier tubes and therefore the rectified B+ can come out on either pin.  If your particular unit uses pin 8 then disconnecting pin 2 will completely remove the B+ from the unit.  The additional current requirements of the filaments in the rectifier tubes are only one reason to go solid state.  The other reason is that you want to completely remove the B+ from the filament winding because the insulation from the 5.0 VAC winding is subject to breakdown over the years from this voltage.  If you leave the 5.0 VAC connected you are still going to have the problem of the insulation breaking down.

Glen, K9STH

Website:  http://k9sth.com


--- On Thu, 6/19/08, Mark K3MSB <mark.k3msb at gmail.com> wrote:

The replacement for the 5R4GY has 3 pins (for pins 8,4, and 2). So,  I need to disconnect only filament pin 2 on the 5R4GY. Is this correct?
 
Similarily, the replacement for the 5V4G has all 8 pins, so which of the filament  connection gets removed?  Filament pins 2 and  8 show no continuity on the replacement.
 
I'm also thinking that I really don't have to disconnect any of the filament pins, although it seems to be recommended.  On benefit of that is that I can use tubes if I needed to.__________________________