I have a Philco 51-930, it just hummed, so I replaced the electrolytics. The schematic shows a 30,40,40, but the one in the radio was a 40,40,40. I replaced it with three 47's. Now it comes on but after a few seconds it starts to squeal. What could be wrong?

:I have a Philco 51-930, it just hummed, so I replaced the electrolytics. The schematic shows a 30,40,40, but the one in the radio was a 40,40,40. I replaced it with three 47's. Now it comes on but after a few seconds it starts to squeal. What could be wrong?
: I just discovered that when I take the back off, which has the antenna attached, & move it away from the radio the squealing stops.

just leave the back off?

::I have a Philco 51-930, it just hummed, so I replaced the electrolytics. The schematic shows a 30,40,40, but the one in the radio was a 40,40,40. I replaced it with three 47's. Now it comes on but after a few seconds it starts to squeal. What could be wrong?
:: I just discovered that when I take the back off, which has the antenna attached, & move it away from the radio the squealing stops.
:
:

Is that the only way? It will look a little strange with the back off.
:just leave the back off?
:
:::I have a Philco 51-930, it just hummed, so I replaced the electrolytics. The schematic shows a 30,40,40, but the one in the radio was a 40,40,40. I replaced it with three 47's. Now it comes on but after a few seconds it starts to squeal. What could be wrong?
::: I just discovered that when I take the back off, which has the antenna attached, & move it away from the radio the squealing stops.
::
::
:
:

Is the shield on the 14B6 tube ?

:Is the shield on the 14B6 tube ?
:
There isn't a shield on 14B6 or any of the tubes.
Thanks