So you acquired an SB-104A...

[N8YX]

Better still, a pair plus a number of spare modules.

What kind of mods are possible? Anyone ever convert the rigs to the WARC bands, add a DDS, get a set of HW-101 concentric knobs and suitable ganged pots then incorporate a front-panel notch filter, RIT or similar improvements?

Discuss...

[wa6mhz]

One thing I did to mine, out of neccessity, but is a highly valuable mod, is to replace the clunky regulator circuits with a better one. It was quite easy infact.

I pulled the 2 pass transistors for the +11V and +5V supplies and replaced them with a pair of LM350Ks. The only addition needed is a 240 ohm resistor and a 5K pot for each, along with a suitable electrolytic cap just for good measure. The 2 voltage regulators are set up for the precise voltage before hooking them up to the circuit, and then again touched up after loaded. The pots are then torque sealed so they won't be messed with again. The LM350K provides far better regulation and current capability than the original MFC6040 Ic circuit.