02-12-2009, 01:48 AM
Hello Micro. As far as bypass-caps values, vintage tube Radios are very forgiving in exact values of uf's as long as same voltage-ratings are met or exceeded. If you have successfully replaced your B+ filter-caps with proper ratings, then you can usually go by any similar schematic ( with same tube lineup) and sub in necessary new by-pass caps ( to replace the old wax condensers/caps) without any major worries. As long as all your tubes filament voltages are close,monitored by your vtvm, & your HV plate Rectifier tube voltages are in the close ballpark voltage ratings for plates HV's,go ahead and sub your new bypass caps one at a time. Anytime a old field-coil type spkr is replaced with a pm type, ( if not original), a suitable size wirewound pwr resistor can be used following schematics. If your spkr is original, no worries! If you have a variac, keep it "fused" with a 1-amp fast blo fuse, protects your ac trans when repairing sets with a ac trans,or ac/dc type chassis & YOU too while servicing your set! Im really not sure the differences between your code 121 & code 122 chassis design, but replacing wax- bypass caps are very forgiving!