Amek m2500 weird noise

Hi
Last day my console start with this weird noise.
I've changed the broken bridge rectifier on -17.5 and the noise is solved but:
Randomly I have the same noise and with oscilloscope I've seen that when there is noise
on the -17.5v output the ripple go up.
The problem go away with meter disconnected ( led meter).
With meters connette the noise is random...
The psu and console are totaly recapped.
All the meters and console are working fine...
Suggestions?
Thanks!

Could be' a weird regulator Lm338k or the booster transistor mj2955?
Thanks!

Sounds like something is dying in the meters, likely a cap.

Thanks for suggestions....
I've discovered that the problem come randomly form main AC .
I think could be a near Motor...
Thanks!!!