[TonyDuell]

Firstly, let me say that I wish all 'first posts' were like this. You have given enough information -- model of the radio, possible faults, and so on -- that we have a good idea what you are doing.

And let me guess that the supplier you mention is Cricklewood Electronics. A lot of us use them and they are generally reliable.

As for the smoothing capacitor can, electrolytic capacitors are never close tolerance components. The 33uF would be a perfect replacement for the original 32uF. And you can always fit replacements with a (sensibly) higher working voltage. 450V ones will be fine here.

You have to connect the -ve leads of the new capacitors together (as you suggest) _and_ connect that to the radio chassis. The original capacitor had the -ve terminal connected to the metal can, and thus to the chassis. Some people here re-stuff the old capacitor, they extract the innards from the can and fit (here) 2 new capacitors inside. It's up to you.

As for the other capacitors, the one you must replace is the one from the anode of the UBC41 to the grid resistors of the UL41. It's C18 on the Trader Sheet (1161) if you are working from that. After doing that, replace the other capacitors one at a time and check the set after each one. Then if you make a mistake you'll know which capacitor you mis-connected.

You might want to remove the capacitor across the mains input (C22 on the Trader Sheet) for the moment, If it shorts the result is spectacular and messy! Replace it with a class X2 capacitor.

In general capacitors under 1nF (= 0.001uF, 1000pF) do not need to be changed. In fact changing them is a bad idea, many of them are used to tune various parts of the circuit and if you replace them you will have to do a full realignment of the radio. This is not impossible, but probably something you don't want to have to do.

A couple of other points about this set. Firstly, it is a 'live chassis' design. There is no mains transformer, the high voltage for the valves is obtained by rectifying the mains directly (that's what the UY41 valve does). The metal chassis of the radio is directly connected to one side of the mains, it might be the live side. So do not touch any part of the insides when it is plugged in, unless you are using an isolating transformer.

Secondly, the valves used in this set have what are known as B8A rimlock bases (that's what the '4' in the valve type number implies). They can only be plugged into their sockets the right way round due to a little bump on the glass that goes into a groove on the metal skirt of the socket. There is a spring ring round the top of the skirt that is supposed to hold the valve in position. Unfortunately it often breaks off the glass 'bump' I mentioned when removing or inserting a valve which ruins said valve. I recommend you remove these spring rings. The valves will not fall out.