Well actually that is good, see easy fix
, just mess around with it a bit. swear,curse at it
it probably is a connection issue somewhere. Could investigate where it is to figure it out for good. Hard to say exactly, could be a flaky component as well. Start checking/inspecting, pushing on the pcb slightly might uncover an intermittent connection or a cracked trace. Giggle some of the wires, it could be one of those wire wrap connections.
At least with it working you can do measurements to figure out what a working unit should measure. A reference point.
Certainly would not hurt to touch up solder joints, inspect for cold solder joints etc.
The ceramic filters are usually thin 3 legged, tan colored, and have a strip of paint on the top usually red to indicate the pass band freq, usually red for 10.7MHz. Usually Murata SFExxx. They maybe also blue too but usually tan. They sit between the Hitachi HA1201 IF amps, in 8 lead black plastic dip package.
Look at the foil picture in the S/M p34, they are just beside the IF i/p from the FE, terminals 8,9 on AWE-040.
If it is working properly, depending where your finger is placed, the capacitance would be shorting the signal out.
Cheers
Rick