Boss TU-2 Input shielding

[gutsofgold]

Working on a Boss TU-2 tuner that hums whether bypassed or on. I noticed that the input jack, which is the typical Boss enclosed style, has copper shielding around it. It sort of has something to do with the hum problem. Is that to keep out frequencies that the digital circuit that controls the LEDS and Screen on the front might cause?

[JasonG]

I know people have had problems with the shielding shorting out the jacks. It could be the problem.

[gutsofgold]

Could you explain "shorting out"? Like the shielding (which touches the input jack plug, acting as a ground) touching the circuit somewhere?

[JasonG]

I think the post I read meant it was shorting out the tip and sleeve . I never had any problems with my tu-2 when I had one so I can't speak from experience.