I notice when I turn my little AWA Champ 4 on it instantly starts a low level hum but no distortion when the station comes on. I did notice however that the top left hand side is quite a bit hotter than the other side. I'm Thinking maybe I need to replace some of the resistors after all. I will be doing this on sunday or monday so any suggestions . It may well be the resistor associated with the electros that were installed backwards. Its sound is awesome but I just want to be sure. I do have hundreds of resistors suitable for this old girl so I will give it a whirl.

I don't consider hotter one side to be much of a guide. How claustrophobic is the cabinet? Manufacturers delight in putting the two hottest valves together in a place where they will cook something: Often the cabinet. They are often together at one end (Rectifier & OP)

What is significant is the condition of the components, in particular all of the electrolytics. At startup the set will be unstable, however transformers tend to rattle growl & cause hum if overloaded. Dodgy filters & leaking caps cause overload.

What is needed is a photo of the inside of the pan. We need to know history, if it still has wax paper caps & very old electrolyitics it will need more than the resistors, that may not actually be the problem.

I check the resistors as I go in any set that I am changing caps in. That saves rework (and possible damage) as you do not have to then go chase them down, when one brings the set down.

Lets think about this before we jump, both feet into the deep end.

Along the lines of what Marc said, as the rectifier and output valve, especially the classic 5Y3G and 6V6G combo are placed close together there can be issues. The Radiola in question features a sealed cabinet and even though there are big air holes on the back, there's no cross-breeze through the radio to adequately cool the air inside. These two valves can easily give off twice the heat of the remainder. Nothing can be done about it really. It's just the way they were made. You could try placing a small fan near the back of the radio to force cool air through but it is often inconvenient.

That said, as the cabinet is a brown one. Significant issues with the Bakelite is unlikely.

I think I will have a go at changing the resistors. As when I first powered it up one of them got very hot and this was before I discovered the electros about face. It should not be a big job. All electros have been replaced and when I said a resistor got hot it actually smoked but I was told not to worry about it. The top of the cabinet gets quite hot but not to the point that you cant handle it.

Check to be sure you didn't install a new electrolytic backwards. They get rather unhappy that way, and will draw current and get hot.

If you are worried about the heat even after you have changed out everything you could always fit a 12v computer fan to stir the air. Various sizes available from old computer power supplys or video boards etc.

A simple diode from the panel light supply would get it running without making to much noise. I'm not sure if it would cause any interference noise though.

Just a thought, at least you would know that the air was moving when the radio is running without having to remember to put a fan next to it.

Given the voltages we are dealing with here I am surprised they didn't go 'pop'. That said, for the sake of reliability, I would change any that were in reverse for new ones.

Not much in the specifics here, so I'm guessing that the "smoking resistor" is the one in the filter, between the 2 electrolytic filter caps. That would indicate that there is excessive B+ current flowing.

Normally caused by a leaky capacitor, or a valve conducting excessive current due to a biasing problem.

I would put it to you that the reason that a resistor got hot is not that it was faulty, it was caused to get hot from working outside its rating. So what is needed, is to ascertain what is causing the overload?

Changing the resistor may be like talking Panadol for a cold & having it clear up in 7 days, or taking nothing & have it clear up in a week.

Marc