Why's it do that? (EE question)

I picked up a 1950's vacuum tube radio a few weeks ago (Traviata AF-610). Works very well (pulls in distant AM signals better than my "real" radios). But it does have a quirk. The volume tends to fall off fairly quickly at about 15 minute intervals. Generally, all I need to do is walk to within about 2 feet of the receiver and it fires right back up; sometimes I have to tap the volume nob (virtually the only metal contact protruding from a lucite frame).

So, why's the volume falling off? Is it just losing the signal and needing me to be a temporary antenna to find it again? Inquiring minds and all that.



Post Edited (09-04-03 13:15)

I don't know the answer although I would try to clean the volume control with tuner or contact cleaner........but continuing this off topic thread:

I bought an amazing antenna that may help me pick up WHCU this season. It was on close out at Radio Shcck for about $10. It is catalog 15-1853. I think that similar loop antennas usually sell for $50 to $90. This is a knock off of the expensive antennas. It was a bargain at its normal price of $30!

Hmm, I wonder if I should try to pick up WHCU bounced off the ionosphere down here. I guess it would probably need to broadcast at higher power to get a decent flux this far away, though.