Simple Audio Modifications for the Johnson Viking Ranger
Warning: Some who have performed these mods have noticed a rise in the resting modulator current, apparently due to ultrarsonic oscillation in the modulator section. If this happens to you, try replacing the 0.02 uF across the modulation transformer with a 0.001 and 0.01 uF and/or the 0.005 across the driver transformer with a 0.001 or 0.002 uF. If the condition persistists replace the original 0.02 and 0.005 uF units.