Adding lower channels to the Browning Mark 3 receiver requires a 31.1 MHz crystal and some rewiring. Gonna use the same module I showed for the Mark 4A.
Adapting the ProgRock module to the Browning Mark 3 receiver is a bit more involved than the Mark 4A receiver. To start, it needs to rectify and filter its own source of DC power. Not a big deal, the rectifier diode taps the 6.3 Volt AC heater power. The filter cap gets the negative lead grounded.
It mounts in one of the vent holes in the deck. Flat washers keep the nut from falling through the hole.
The tricky part is rewiring the front-panel band/crystal selector. The fixed-crystal receive feature gets removed altogether, so it has three tuneable bands.
Gotta dig out a photo model of each Mark 3 receiver version. The first one from 1970 had only one tuneable band and two fixed receive crystal sockets. The later version had two tuneable bands and one fixed crystal socket. The nitty-gritties of the modificaton are not quite the same. Need to shoot pics of each version. Removing the fixed-crystal feature from the Mark 4A is a lot easier. Remove one wire, shorten another and solder it to the foil pad where the removed wire was.
That's the next step, detailed instructions with pics.
No rest for the wicked.
73
Adapting the ProgRock module to the Browning Mark 3 receiver is a bit more involved than the Mark 4A receiver. To start, it needs to rectify and filter its own source of DC power. Not a big deal, the rectifier diode taps the 6.3 Volt AC heater power. The filter cap gets the negative lead grounded.
It mounts in one of the vent holes in the deck. Flat washers keep the nut from falling through the hole.
The tricky part is rewiring the front-panel band/crystal selector. The fixed-crystal receive feature gets removed altogether, so it has three tuneable bands.
Gotta dig out a photo model of each Mark 3 receiver version. The first one from 1970 had only one tuneable band and two fixed receive crystal sockets. The later version had two tuneable bands and one fixed crystal socket. The nitty-gritties of the modificaton are not quite the same. Need to shoot pics of each version. Removing the fixed-crystal feature from the Mark 4A is a lot easier. Remove one wire, shorten another and solder it to the foil pad where the removed wire was.
That's the next step, detailed instructions with pics.
No rest for the wicked.
73