Marshall valvstate issues

[theycallmebrown]

so i got an issue with my amp here and i was hoping for some help. when i plug my guitar into my marshal avt 150h i got a very low sound output. i cleaned all the connections with electrical cleaner and bought a new preamp tube and still get a sound with no power behind it. ive tried several differnt guitars and cables. when i move the input jack around ill get loud noises and when i have the distortion channel on it gets real loud but its not playing the sounds the guitar makes, its all just random static noise. i think it has something to do with the chip that the input jack sits on. has anyone had this problem or know where i can order that chip from?

[FastEddy]

Gotta poke around in there with a volt meter and see of the power supply side has any meat and potatoes ... and you might ask the kids over at the "musical instruments" part of this forum.

Is it worth taking to the shop?