jvc rv-nb1 strange noises

hi, ive got a kaboom rv-nb1 and ive managed to replace the cd laser and the belts for cassete drive.
but i got strange noises on radio source and cassette.

if i tip on radio it sounds like näääääää but only if the volume set to 1 or higher on zero there is no noise, if the volume is set higher the noise is on the same value and goes not louder with the volume, the radio station is clear but the noise is everytime in the background

on cassete its the same noise

does some one has a clue where i can find the source of this noise and can help me to find a solution to get rid of it?

Sounds like a reassembly issue. Any chance you have damaged something in the process? Maybe a ground wire has come loose?

Ok, ive now disasembled the BOx again and i have interchanged the CDPlayer+bottom Mainboard Unit from a RV-B99 so all other things in the NB1 seems to be OK because there is now no Noise.

the other thing is if i plug in a headphone into the Noisy Board ther is no Noise over headphone

i hope i have cut down the posibilities where the Noise generator is and some one can advise how to repair it