Problems with Zenith K731

[gdunlapsd]

Hi,

My name's Greg and I'm new to this forum.

I recently acquired a Zenith K731 radio via ebay and am trying to get it up and running. It was "working" when I got it, both AM and FM, but had a loud hum and barely any sound from the stations. I just recapped it with 3 electrolytics to replace the multi section can and film caps to replace the paper caps, and the improvement was remarkable.

However, when I installed a 1N4007 diode with a 68-Ohm 2watt dropping resistor, as soon as I turned it on the resistor started to smoke! Of course I immediately switched it off. I wired the selenium rectifier and stock dropping resistor back in and it worked fine again. Triple-checked my work, no shorts, tried the diode and new resistor again, same result. Resistor measures good, tried another one anyway, same result. For now I'm back to using the selenium rectifier, which is, for now working. I'm quite puzzled - where did I go wrong? I've read of others using the same diode/resistor combination successfully. The chassis on mine is the 7K07.

Another issue - FM was working though quieter than the AM side, was listening to a station for a while when it suddenly seemed to cut out - now FM's really quiet, does work but I have to crank up the volume. AM is still nice and loud. Even before it went quiet there was slight distortion (not horrible but I could hear it on the Ss's) and treble wasn't too good (AM actually sounds much better). Some low hum on FM as well - doesn't seem so much on AM, but there's a lot of AM noise around where I live anyway so it's hard to tell for sure.

What should I look for first? Bad tube, resistor, cap? Unfortunately I don't have any tube testers or much else in the way of diagnostic equipment - just a Rat Shack multimeter.
Any tips on what I should look for would be greatly appreciated!