[exray]

Those Zenith xfmrs do run hot and 20 ohms should have taken you down to a safer voltage range. Many folks have abnormally high house voltage (125+) but if you can get the voltage down to say 110-115 via the resistor then it shouldn't stand out as being hotter than any other radio. Measurements with a meter will tell the story. Shouldn't take as much as 150 ohms, but... It all depends on your starting point whether or not you need to drop that much.