[Milsurplus] AR-88LF Oscillation

[Joe Connor]

I'm working on a nice AR-88LF with Royal Canadian Air Force markings. Any help would be greately appreciated. 

I ran into something strange in the first AF stage that I need help with. R-38 (1.5 MEG) had been removed from the circuit and replaced with a 4.7 Meg resistor. When I put a 1.5 Meg unit back in, I got a low frequency oscillation. With some trial and error, I eliminated it by changing C-112 from .25 mfd to .05 mfd. With the .05 mfd in the circuit, the voltages in the 1st AF seem fine and the set plays very nicely.

Any idea what's going on? Should I leave the .05 in place?

                              Joe Connor