[bridkarl]

For resistors I try to check them first. 20 percent is fine. 
Assuming you get the radio working - I sometimes do everything else, get the radio running, let it run for an hour or two and then check the resistors.

I think these carbon resistors sometimes absorb water - especially if stored poorly like a basement - so running the radio heats it up and drives the water out. 

It may be an old wives tale, but I’ve measured out of spec resistors before and after and sometimes the resistor goes to its proper value. Lots of times they’re too far gone but sometimes this seems to work.