When I initially checked the carrier balance awhile back it looked like this pot (R21) was set correctly. Today, I attempted to do the filter match alignment (Sec 5.9 in the instruction manual). The instructions call out rotating this pot to max CCW. However, the shaft continuously rotates with no mechanical stop. I then noticed that the resistance value did not change as the shaft was rotated. I disassembled the pot to see what was wrong. The problem seems to be that the bearings don't rotate when the shaft rotates, and since the armature is connected to the shaft via the bearings, the resistance does not change. I have never seen a pot like this and wonder what it is about this circuit that required such an unusual pot? I assume that the preload needed to turn the bearings no longer exists, but I don't see any way to adjust that. Am I missing something? Can I just replace this pot with a standard 200-ohm pot (without the bearings)?
--
Bill N0CU
