I’m finally getting around to working with my SW-3 receiver (type 36 & 37) and it doesn’t use the normal 4 pin “plug & play” supplies. Looking at the schematic tells me there is 135v and 67v labeled B+ blue and green. There is the 6v filament on two leads with a 5th lead labeled yellow that appears to ground the 67v B+ voltage supply through some supply resistors. It’s labeled B- so I’m assuming it is connected to both negative B+ or is connected to the 135v high side if I’m using a dropping resistor to get my 67v.?
Does all this sound right or am I headed to a smoke escape event?
Thanks,
Tom N5AMA
