[R-390] My Lesson in Carrier Meter Problem - Never Overlook the Obvious

[Barry]

After rebuilding FL101, replacing CR801, and installing dropping resistors for the Antenna Relay and Break-in Relay, I powered up the R390 only to find that not only is the B+ 5 volts low (different thread), the Carrier Meter would not drop below about 2/3 scale.  I could monitor the AGC voltage with an HP410C and verify it was working; however, after checking the pertinent tubes and their voltages and resistances I still could not determine why the meter was reading so high.  As I recall, before doing work on it, it seemed to be working correctly and was thinking I had fouled something up in the process of the work I'd done and since I hadn't touched the CARRIER LEVEL ADJ pot, I should leave it alone.

I finally decided that all things must to be pointing to the CARRIER LEVEL ADJ pot.  Sure enough, it appears to have developed some high resistance at the wiper and exercising it allowed me to set the meter zero point as it should be.  For whatever reason, I just couldn't convince myself to make that adjustment until I finally did.  Lots of wasted time when I should've gone with my instinct.  Lesson learned I suppose.

Thanks,
Barry - N4BUQ