Golborne Vintage Radio

I felt I needed something to keep me "out of trouble" over the Christmas break so I purchased this little PYE47X bakelite radio that appeared in a local charity shop for the princely sum of £7.50. It looked a wee bit sad for itself but the case was (under all the grime) intact. The plastic window had become loose & was almost opaque, oddly yellow but that was our old friend cigarette smoke/kitchen fumes. It had obviously been repaired at some point in the past but a long time ago. All the waxy's over 0.1uF were leaky/blown up/pre-bubbled. Most of the resistors were way out of their 20% tolerance as well, oddly there were two 1M's that were 'intermittent', out of circuit they would measure about 1M but if their leads were stressed this figure would drop to about 200K! Most odd. The valve line up was standard apart from the output valve, this was supposed to be a 35L6GT, in this one there was a 50L6GT, same valve but different filament voltage. After the usual clearing out of the accumulated dust/dirt/spider remains & cobwebs it was looking fairly ok. This set differs from most in that it uses variable permeability tuning & reflex IF rather than capacitive to tune different stations, quite a novelty in some ways. After application of switch cleaner to the volume pot & wave change switch it was time to apply some power. This, for me at least, is always a nerve wracking moment! It doesn't seem to matter how many times I check I ALWAYS check again, just to make sure. As this is an AC/DC set I decided to use the lamp limiter, all appeared well initially. After about 30 seconds or so there was feint noise from the speaker, with an aerial attached it successfully pulled in a few local MW stations. Then I notice smoke! Heck! Where was that coming from? And why did it smell of talcum powder?!? It was, of course, the dropper burning off years of accumulated dust & moisture. Over several cooling/heating cycles this has now stopped but that dropper gets mighty hot, I may have to re-visit that just for my own peace of mind. As to where the set will go now I have no idea, no doubt a place will show itself, eventually.........
One note before I forget, although the trader sheets for the PYE47X & Invicta200B are very similar there ARE some subtle differences, R2 being one of them!

The Trader index says sheet 858 for the Pye 47X but the sheet itself says Invicta 200. Could you please clairify? Is there another sheet that's specifically for the Pye?

That dropper has a lot of dropping to do. There's only 94V on the heater chain so for 230V mains in a 150mA chain that's over 20 watts. A capacitor dropper would work out at around 2.2uF. Perhaps a smidge higher because you've got a 50L6GT in there but it's not going to be that critical.

As devout coward, and mainly playing with TVs rather than radios, I believe in getting the heater chain working first, before gently applying HT. Perhaps not so vital for a radio.

PS: I hope that the charity shop was selling the set for display only with the mains lead cut off. It wouldn't be legal to do otherwise unless it's properly safety tested which would mean signifcant resotoration too.

I was working from the PYE radio servicing documentation which agreed with my example. R2 is 330R to V1 in the service sheet whereas the trader sheet has R2 as a 47K in the aerial circuit. The service sheet agreed with my example therefore I used that. Yes, I did think the dropper would be working quite hard & did consider the capacitive dropper option, perhaps when I get time to re-visit it. Right now I've got a Defiant MSH902 on the bench & very little information about it!

The component numbering is usually different when you compare a Trader sheet with the manufacturer's own data. I don't know why Trader not only redrafted circuit diagrams but also changed the component numbering. I can understand redrafting to make it fit a Trader sheet but not renumbering.