Well I waved the white flag and gave up after finding way too many things that had been tinkered with. I dumped the unit but kept the chassis speaker and dial in the hope I find another one day! For the meantime il keep listening to my ever reliable Krieslers!

100 Watt 240V globe in series with mains, valves removed, turn it on!
Then measure AC at the rectifier socket and filament voltage.
Anything seriously wrong will firstly cause no harm and be indicated by the globe.
Please report back, I'm sure people here can talk you through a total fix.
Let it run for an hour or so in this condition, everything should stay basically cold.
JJ

I will definitely use that strategy to fire up my next project! The more I looked at this the more I can see has been interfered with and the latest problem was a broken valve socket that I hadn't noticed before.

If the radio was in good nick I'd have pressed on but I know it was becoming too difficult - I'd rather put that amount of time & money into one worthwhile.

I kept the important bits of this one and going to try and find another - then i'll have an assortment of spare parts!

Black inside a valve is not an indication of a fail, more the reverse. If its a brilliant white or a light brown, then you are likely to have an issue: Gassy.

There is not a really good way without equipment to tell if a transformer has problems when dead. You can use an ohm meter initially to check continuity and then remove the rectifier to disable B+.

I normally Insulation test the primary windings per Tag & Test (500VDC), but also extend that to all windings and winding to winding. If one has burnt into the other, that hopefully shows. Not withstanding that if RCD's are fitted & primary leakage is excessive, power will be removed rapidly.

The only thing after that lot is to apply volts & measure all the ac volts (Rectifier still removed). Shorted transformers often "Growl". If its shorted it will get seriously hot. The insulation on many of those transformers was hard & will not support combustion. One of the worst transformers I have seen is fitted to my Philips 132L and several other models. Its wrap material is flaky and often the winding exits the side of it.

I normally fire up a radio (or similar e.g. BC-221-N is not a radio) with a voltmeter on the "B" . If things are not going to plan, I hit the kill switch.

Marc

Well I waved the white flag and gave up

I think you gave up too soon. Many 6AQ5's are totally black, there's normally no problem. Also a bit of wax does not necessarily spell the end of a transformer.

Yes I agree, you gave up too soon.

The series 240v lamp approach is highly recommended.

Do it 1st with all valves removed, the lamp should not light. If it does, transformer is stuffed. If not, next step.

Plug in the rectifier. The lamp should light dimly for a few seconds then go dimmer. After about 2 or 10 or 15 seconds depending on the rectifier type it will get brighter again as the rectifier warms up. It should then fade back to its intermediate brightness.

If the radio has not been powered for a very long time, the lamp may fade very slowly. In this case, unplug the 100w lamp and replace it with a 15 or 25 watt lamp. This will reduce the current and let the electros re-form without exploding. This may take many hours, even a day or so. But you are safe, if anything goes wrong the lamp will light and save you from fire etc. You may not even have to replace the electros.

Sounds like your radio has chassis-mount electros, they must be there somewhere....

If the lamp does NOT fade at all, you probably have a B+ short circuit.

Hope this helps.