Resistors going high is probably more important to checkout than replacing all the caps.
I'm not in favour of just replacing all the caps anyway.
One may even consider that the engineers who designed these radios at the time used the slight leakage in some caps as
an advantage to a particular circuit.
With experience one learns which ones to throw out, as a preventative maintenance measure.
With resistors, it does not take long to check them. Anything over 100k for sure.
And all cathode resistors.
All caps should be checked, and really all that are connected directly to HT replaced.
Over the years I have repaired many man made faults by persons just replacing a heap of parts for no good reason.
But I love everyones enthusiasm, JJ

Here there are no different standards for a home fix, or a commercial one. The idea with a commercial fix here, unlike many serviceman of old, is to fix it once and not have it continuously coming back as bits fail.

In fifty plus years you do get a feel for what commonly goes wrong with certain models and parts. Sets with early electrolytic caps and those not run for an indeterminate period, should never be powered and the same applies to waxed paper caps & oil filled types.

I will only power a set if the customer brings it in working badly and often that won't happen if I know what the fault is or the wiring is dodgy.

Rarely do I find a radio or piece of valve era equipment with parts that are all in spec. I would never send a radio out without checking resistors.

Nor will it go out without the mains circuits being tested, as per test & tag requirements and made safe (Transformer sets) AC/DC sets are not intrinsically safe when missing bits, or out of cabinets.

Marc

Yes good sound logic Marcc and I guess I can understand Johnny how circuits were designed considering the nuances of available parts at the time, the caps in this radio really looked dodgy although the radio worked fine, I've found 2 6M5 valves on Ebay, so I can wait until they arrive and if it doesn't spring into life, back to the drawing board.. Output transformer etc... It'll have to go on the backburner!
I've replaced all of the caps in four radio's now, which benefitted greatly and work better than before, my resistors have arrived, a kilo or more 85 values! Unfortunately metal oxide not Carbon fillum... Which are apparently the ones I should have got, but they'll have to do as I have more of the damned things than I can poke a stick at... Only problem is I'm colour blind so I'm going to need to beg my wife to help me and I'm still working out how to cross that bridge! With the least "resistance" lol

Use a digital meter for the resistors, thats the easiest way.
I doubt that the 6M5 is faulty, unlike transistors valves are fairly hard to kill.
If the output transformer is OK continuity wise the chances are its OK.Use a 9 volt battery as suggested.
Even when they overheat, they rarely go shorted turns.
Unless of course the plate has been shorted for some considerable time.And its really cooked.But you would smell that.
On my work bench apart from a 10mA earth leakage detector and then isolation transformer, I then have a 100 watt light globe in series
with the socket which the repair plugs into.Then when a radio is normally used the globe doesn't even glow and if there is a fault
or starts to for example draw 100mA then the globe glows. Dead short and the globe is approx 100 watts bright, and the power transformer in the radio does not burn up.A good indicator which allows you to disconnect fast if necessary.
I then have a switch which shorts out the globe when all is good.JJ

That's a brilliant idea Johnny, pardon the pun, better a lit globe than a cooked tranny! I'll make something up, 100w incandescent globes not as easy to come by anymore, but I'm sure I'll find one somewhere! Thanks for the tip mate, cheers.

100w incandescent globes not as easy to come by anymore,

Use two or three smaller wattages. Can even switch them in or out.

One thing that you will find handy is the IC clip. I use them on the meters testing caps etc. as that renders it a no hands needed and less likely to get bit. More importantly I use them in conjunction with an analogue meter to monitor "B" voltage on startup.

There are cases (& I have had one this year) where the cap gets to a certain voltage & lets go, drawing current at a hyperbolic rate as the voltage rises:Perhaps. What should happen on startup is predictable. Filament rectifiers, with no cathode sleeve, solid state diodes & the like will rapidly provide a surge voltage of close to twice EMF, that sags as the heaters start conducting. Heater rectifiers have little surge.

So if you start the set with a monitor, you can take appropriate action (kill), when the voltage perhaps stalls at a low voltage. The last one I had die on start was a allegedly new 500V one that let go at 450V.

Well well well, how good it is having two identical radio's!
Finally decided to get this one sorted once and for all. I opened up both radio's the pink working one, which I successfully re-capped, and this poor set, to find upon a thorough examination, one had a cap soldered to a different point. Of course forgetting which radio was which, I set about correcting the problem to find it no-workey, hmmnnn...
put it back how it was and it was full of life, so corrected the other set, soldering the same cap exactly the same as the workey one and now both workey!
Re-assembled both radio's and now both are working fine, so ends this post!
All good!!!