[Boatanchors] Navy RAL Questions

[Joe Connor]

Guys, I have a question -- probably the first of many -- on a Navy RAL that I picked up at a swapmeet today. 
When I got it home and took it out of the case, I found that it had been the home to a family of mice who left many calling cards. Quite a mess. I figured there was no way I would ever get this set working again, but I figured what the hell and hooked it up to a good Navy power supply. Damned if it didn't work. Go figure.
Here's my question: my filament voltage is low, about 4.8VAC. The power supply is putting out more than 6VAC, and I used 16-gauge wire for the filament hook-up. As I look at the schematic, there's not much in the filament chain. There's an AC voltmeter (not working at this point), but disconnecting it didn't increase the voltage. I disconnected the two leaky AC bypass caps, and that gave me an added 0.2VAC. The B+ and screen voltages are good. 
Any ideas? Might dirty tube pins do it? I haven't run into this before; usually filament voltage is the one voltage you can count on to be right. 
I've attached the link the manual, and the schematic is on p. 56.http://bama.edebris.com/manuals/rca/ral/

As always, thank you for your guidance.

                                 Joe Connor