Fender "THE TWIN" Red Knob Twin Ground hum or loop eliminated by touching guitar bridge

[Jquijano]

My Fender 1990 Red Knob Twin was finally fixed by a certified technician. Nevertheless i am experiencing a loud hum that is reduced whenever i touch the guitar strings or bridge. Is this an acceptable hum? Is there a way i can eliminate this? Anyone? I dont have this problems with my 1989 Marshall JCM 800 50 Watter or my 1991 Fender Twin Reverb. Same house and same electric current. Anyone?

[The Dude]

You already posted this question in another thread, but did not reply to the question posed there. Why start another thread?

https://music-electronics-forum.com/...ucial-problems