[grandntl]

Hi everyone, I have a Philco 91-121 that has the electrolytic and bakelite block capacitors replaced along with many new resistors; I bought it that way. ( The blocks were bypassed so I can see the capacitor values).  My signal generator is not currently working so I  found that the oscillator was running at 268 khz above  a received station using a digital radio and I peaked the IF transformers for maximum narrowing of the working shadow meter on several stations . All seemed well except that when I removed the one piece tube shield all stations came in significantly stronger with no squeals etc. With the shield in place and I touch the grid cap of the 36 detector/oscillator the reception also improves. What is causing this and thanks in advance for responding.
Bob