Philco A547B (1948) fixed - UK Vintage Radio Repair and Restoration Discussion Forum

MurphyNut · 19th Mar 2020, 10:36 am

I have a mental list of radios I’d like for my collection and the Philco A547B for some years was on it.
I’d never seen one in the flesh but from the pictures on the internet it appealed me, it looks solid and purposeful and of course I’m a sucker for anything make of Bakelite.
So it came as a pleasant surprise whist strolling around the big Kempton collectors market I spotted the back of an old valve radio. When I walked around to view it from the front it was the said Philco. I was very surprised at how big this set is; from the images I’d viewed I imagined it much smaller.
This didn’t deter me, I had a good look over it, no damage and nothing missing, we agreed on a price and I proudly carried it back to my car.
Back home, on taking the chassis out from of the cabinet I quickly noticed evidence someone had worked on it, but not much, just an electrolytic capacitor and new mains lead.
On powering it up it did very little, the pilot bulbs came on and a very faint crackle when the wave change switch was selected.
I set about replacing all the wax capacitors and that radiospares electrolytic; this had completely failed and was the wrong value anyway. The smoothing caps were reading spot on so I left them. The wave change contacts were cleaned with Servisol. A few rubber components were replaced and I gave it another go.
I got some sound but not much, just two or three strong stations but very quiet and horribly congested sound.
I was thinking it might be a valve problem, I soon found out most of the valves in this set crop up other sets in my collection. So I found known good ones and tried them in this set. No change at all, so that ruled that theory out!
I wasn’t sure what to do next so I contacted and good friend and experienced radio restorer and he pointed me in the direction of troublesome resistor often found in this model.
He was spot on; the 220K resistor was the culprit. (R18 Trader sheet 890) I’ve since spent time looking up people restorations of this model and on more than one occasion this resistor is mentioned.
It now sounds great, very loud and sensitive; I can even pick up stations without an aerial. Cosmetically it was easy getting it looking good, simply a good polish and it’s now nice and shiny and almost looks like new.
Nice set, I’ve been listening to all the virus doom and gloom on it most of the day!

ronbryan · 19th Mar 2020, 1:19 pm

Clive

Did you mean R14 220k, the triode anode load on Trader Sheet 890, instead of R18, the AF feedback resistor?

Ron

Lloyd 1985 · 19th Mar 2020, 1:50 pm

Nice work and good tip about said resistor, I’ve got 2 of these sets and neither of them work! I’ve not tried any restoration on them, in fact I was looking to part with one to free up some space.

Looks nice all polished up, maybe I’ll have to give one of mine another chance

Regards
Lloyd

MurphyNut · 19th Mar 2020, 4:40 pm

Quote:

Originally Posted by ronbryan

Clive

Did you mean R14 220k, the triode anode load on Trader Sheet 890, instead of R18, the AF feedback resistor?

Ron

Thanks Ron, looks like I got that bit wrong.

Phil G4SPZ · 30th Mar 2020, 8:26 am

Nice work Clive, that’s a fine-looking set.

19th Mar 2020, 10:36 am	#1
MurphyNut Heptode Join Date: Apr 2016 Location: Croxley Green, Hertfordshire, UK. Posts: 979	Philco A547B (1948) fixed I have a mental list of radios I’d like for my collection and the Philco A547B for some years was on it. I’d never seen one in the flesh but from the pictures on the internet it appealed me, it looks solid and purposeful and of course I’m a sucker for anything make of Bakelite. So it came as a pleasant surprise whist strolling around the big Kempton collectors market I spotted the back of an old valve radio. When I walked around to view it from the front it was the said Philco. I was very surprised at how big this set is; from the images I’d viewed I imagined it much smaller. This didn’t deter me, I had a good look over it, no damage and nothing missing, we agreed on a price and I proudly carried it back to my car. Back home, on taking the chassis out from of the cabinet I quickly noticed evidence someone had worked on it, but not much, just an electrolytic capacitor and new mains lead. On powering it up it did very little, the pilot bulbs came on and a very faint crackle when the wave change switch was selected. I set about replacing all the wax capacitors and that radiospares electrolytic; this had completely failed and was the wrong value anyway. The smoothing caps were reading spot on so I left them. The wave change contacts were cleaned with Servisol. A few rubber components were replaced and I gave it another go. I got some sound but not much, just two or three strong stations but very quiet and horribly congested sound. I was thinking it might be a valve problem, I soon found out most of the valves in this set crop up other sets in my collection. So I found known good ones and tried them in this set. No change at all, so that ruled that theory out! I wasn’t sure what to do next so I contacted and good friend and experienced radio restorer and he pointed me in the direction of troublesome resistor often found in this model. He was spot on; the 220K resistor was the culprit. (R18 Trader sheet 890) I’ve since spent time looking up people restorations of this model and on more than one occasion this resistor is mentioned. It now sounds great, very loud and sensitive; I can even pick up stations without an aerial. Cosmetically it was easy getting it looking good, simply a good polish and it’s now nice and shiny and almost looks like new. Nice set, I’ve been listening to all the virus doom and gloom on it most of the day! Attached Thumbnails __________________ Clive

19th Mar 2020, 1:19 pm	#2
ronbryan Octode Join Date: Jan 2003 Location: Guildford, Surrey, UK. Posts: 1,959	Re: Philco A547B (1948) fixed Clive Did you mean R14 220k, the triode anode load on Trader Sheet 890, instead of R18, the AF feedback resistor? Ron

19th Mar 2020, 1:50 pm	#3
Lloyd 1985 Nonode Join Date: Jun 2008 Location: Coningsby, Lincolnshire, UK. Posts: 2,819	Re: Philco A547B (1948) fixed Nice work and good tip about said resistor, I’ve got 2 of these sets and neither of them work! I’ve not tried any restoration on them, in fact I was looking to part with one to free up some space. Looks nice all polished up, maybe I’ll have to give one of mine another chance Regards Lloyd

30th Mar 2020, 8:26 am	#5
Phil G4SPZ Dekatron Join Date: Apr 2005 Location: Bewdley, Worcestershire, UK. Posts: 4,748	Re: Philco A547B (1948) fixed Nice work Clive, that’s a fine-looking set. __________________ Phil Optimist [n]: One who is not in possession of the full facts