Ts4d Motorola

[tom.j.fla]

1N4007s' and like diodes generate a lot of noise, they are bypassed by 0.001ufd disc caps. min. of 500 volts wired across the diode . You have another set try subbing V1,V4,V6, and V11 one at a time to see if any thing changes. If no change then start checking layout of A.C. power wiring if to near audio stages move the leads away from the audio wiring. All the best, Tom