The small PCB takes the redundant 12V heater winding from the HT transformer, voltage doubles and rectifies it to provide power for the soft start relay, the 28V coax relays and the TX/RX changeover relay. The board is mounted on top of the heater transformer. I use a seperate heater transformer so I can run the heater and blower for 2 minutes before applying HT to the GS31b.
|