HT-44 tune up issue

[N4RMT]

Hey guys.

I have a Hallicrafters HT-44 that tunes up wonderfully on 40 and 80.  20 and 15, however, not so much.  When I try to tune for 15,  as soon as I begin to advance the driver tune, the rf output needle virtually pegs, and then if i try to correct it, it dances all over, and I can hear a sizzle sound.  Is this oscillating?  I've cleaned the band switch with contact cleaner, but the behavior didn't change.  Once again, the rig tunes up nicely on 40 and sounds good according to on the air reports.  The tubes are all labled "Hallicrafters", so I'm sure they're the originals.  I don't have a tube checker (God I'd kill for a Hickok 600!).

[Pete, WA2CWA]

The sizzle could be a short; it could a tube audibly oscillating; could be a bad or poorly soldered connection. Find someone to test the tubes. Diddling with tube boatanchors, and not having a tube tester, is like walking in the dark. Given its age, leaky or shorted caps could be a problem. Resistors out of tolerance could be a problem. A scope can be very useful in isolating the problem. Check all the voltages and resistances on the tube pins.

[N4RMT]

I went through and did a more thorough cleaning and inspection.  Made an order for caps and resistors, although most checked out to be within spec.  The thing acts fine now, but I'm gonna replace these components anyway.  Especially the caps.  Bought a tube tester too.