Hallicrafters SR-150 Operation And Maintenance Manual page 33

RX GAIN ANOMALY CONT.
Now it's back to the initial SR-150. I pulled the control, a rather fun chore. Got on the internet and found that
10kX500K ganged controls aren't readily available. So I disassembled the pot and painted the landing area for
the wiper at both ends of the pot with three thin coats silver paint. The paint is a product developed to repair
printed circuit traces. I re-assembled the pot and retested the rig and what a pleasant surprise. Prior to the pot
repair it took 0.8uv to get 500mw of audio output, now it is 0.4uv. The AGC hit linearity at 25uv before, now it
hits linearity at 3.5uv. The AGC figure of merit holds to 65db over 5uv (spec is 50db over).
I believe the construction of the pot precludes any of the controls from reaching ideal 0 ohms and that the vast
majority of rigs would benefit from some type of corrective action. I bought my ½ troy oz bottle of silver paint
about 5 years ago for $22.00. That same bottle now goes for $42.00. The GC part # is 22-023 and is RoHS
compliant. There is a MG SILVER PRINT CONDUCTIVE PEN product available for $22.95. I have not used
this pen but it should be quite similar. If all else fails then BING "SILVER CONDUCTIVE PAINT".
By Walter Cates WD0GOF (UPDATE 10/30/2013) 33