My first restoration project. Emerson Model 503. - UK Vintage Radio Repair and Restoration Discussion Forum

ct92404 · 10th Dec 2015, 7:12 am

Hi group,
I've been here for a little while now. First of all, I'm actually in the United States but I found this website a short time ago on a Google search and I really became hooked.

I especially enjoy reading the posts where someone has taken an antique radio or television that was neglected and falling apart and looked totally hopeless, and managed to restore it and get it working again. It's truly amazing what some of you guys have been able to do!

I've always been fascinated with old vacuum tube radios. They were well before my time, but I love antique electrical and mechanical things in general. A couple of weeks ago, I bought an Emerson Model 503 tube radio from an antique shop. It was in REALLY sad shape. The case is made out of wood, and there were chips and gouges in many different areas. It was also completely filthy, and was missing the antenna coil and rear cover. Still, I fell in love with this thing because it just looked incredibly old. Also, even though it was in bad condition, it did seem to have all the parts in the chassis, and I felt that I might be able to fix it.

http://i45.photobucket.com/albums/f8...psuie9qopq.jpg

http://i45.photobucket.com/albums/f8...psygltpsaq.jpg

I looked up this radio, and I found out that this model was made in 1946! I have a collection of a few other antique tube radios and this is now the oldest one I have. But in order to save it, it was going to need a LOT of work. It was a major project. I've never tried to fix an antique to this degree. I've only replaced filter capacitors before that that's about the most I've done. When I plugged in the radio and switched it on, it did power up and the tubes lit up. But of course it didn't work, and there was a very loud hum. I started by taking the chassis out and thoroughly cleaning it and the wooden case. The chassis had a little bit of rust and probably decades of dust and grime on it. I then replaced the electrolytic filter capacitor. That got rid of the hum. But of course the radio still couldn't pick up any signals because it didn't have an antenna coil. I had to make one. I've never made a coil for an AM radio like this before, so I really wasn't sure exactly what gauge wire to use, what length or how many turns, etc. I had to experiment with many different coils I made. But finally I made a long coil with 28 gauge magnet wire (American Wire Gauge, I'm not sure how you guys categorize it). That worked, and now the radio has great reception.

The next step was to restore the wood case. That was a HUGE amount of work too. I patched up the areas that had chips with wood putty, and some corners also had big gouges where the corners had to be reformed. Then I sanded it, filled more with putty, sanded again to make it as nice and smooth as I could. Then I painted it. Because I had to use putty to repair the case, I couldn't use varnish. So I used paint that was as close to the original color as I could get.

It's not perfect, but I think the radio sure looks a HECK of a lot better than it did!

http://i45.photobucket.com/albums/f8...psjz76ztby.jpg

http://i45.photobucket.com/albums/f8...psucxsibhz.jpg

http://i45.photobucket.com/albums/f8...psctkn7inq.jpg

I decided to make the rear cover smaller just so plenty of air could get inside to keep the radio cool. I might make a different cover later, but for now I think it's okay. You can see the homemade antenna coil I made.

The radio works VERY well now. I can pick up AM stations very loud and clear...in fact, it actually sounds better than some of my other radios which I have never had to fix! I'm really happy with how it turned out. There is one part in the front where the paint or varnish came off and so I'll have to see about repainting the front later. You might be able to see that in the bottom left corner. But overall, my first restoration project seemed to go well!

joebog1 · 10th Dec 2015, 7:32 am

I agree with that !!!
NICE job
regards
Joe

raditechman · 10th Dec 2015, 9:27 am

Well done.
I hope you checked the coupling capacitor on grid of V4 the audio output tube.(50L6GT?)
This is fed from the plate of the preceding tube and if it goes leaky puts +ve on the grid.(not healthy!)
I think in your set it is C13 and .02mfd.
This is sometime called "that capacitor" on this forum. It is important to check and replace.

John

Peter.N. · 10th Dec 2015, 12:24 pm

Nice restoration that. I have an affinity for pre war USA radios as we had quite a lot over here in the '50s fitted with resistive 'line cord' to 'lose' the other 110 volts. They were mostly very compact, much smaller than most UK radio's of the time.

Peter

ct92404 · 11th Dec 2015, 1:33 am

Thanks for the replies everyone!
And no, John, I did NOT check that capacitor...I didn't even know about it! I'm still pretty new to all this. I do have a little experience with electronics, but I'm still new to working on these old tube radios and I have a lot to learn. I will look for that capacitor and check it. Thanks for the advice! So could it actually cause damage to the tube if it is leaky?

- Chris

joebog1 · 11th Dec 2015, 2:50 am

Its one of "those" capacitors !!! If it leaks it will reduce/change/apply a different DC potential to the grid. That will cause the valve to cunduct too much current.
Normally the distortion would give an experienced person the hint, that something was not well. As you are just beginning on one of the best hobbies you will ever have, its one of the best places to start. If it needs replacing its cents only, but at worst it could fry both the valve AND the output transformer, and perhaps because of the extra large current draw, take out the rectifier, AND the mains transformer. This is of course, WORST scenario.
BUT you will find it fun to do. BE VERY careful of high voltages!!!!!
Death is permanent!!
I think first you will need find the circuit diagram that we can all look to. That way you will have many questions asked by us, as well as you asking many questions of us "why" ?

Best regards
Joe

ct92404 · 11th Dec 2015, 4:07 am

Yikes, okay I'm definitely going to look for that capacitor then. And it's called the "coupling capacitor"? I looked it up online and coupling capacitors are used to pass alternating current, while blocking DC, is that right?

Now that we're talking about this, what would a radio sound like if that coupling capacitor was going bad? I have another antique tube radio, a Zenith model F508L radio, that seems like it might have some kind of distortion going on. It's just a small plastic desktop radio. It works well, but I have noticed that it sounds a little "crackly" if that makes any sense. There's like a faint high frequency hissing in the background. I always thought that was just normal for some old tube radios, but could a capacitor be a problem?

joebog1 · 11th Dec 2015, 5:52 am

May very well be !!
You really need a reasonable multimeter, AND read the manual for it.
A modern digital is OK, its NOT as nice as an old Simpson or similar, a VTVM being the best for valves.
Modern digital stuff keeps counting and counting and counting, UNLESS the voltage/signal/measurement point is as stable as the rock.
An analogue meter moves as much as the digital does, BUT its much easier to read "about" 10.5 volts rather than 10.723546 10.4678465 10. 41482489 etc etc.

Joe
I read LOTS of adds from USA about ex-military, NASA disposal stuff that I positively DROOL over. BUT added to USA post, and the weight of "old decently built" stuff its prohibitively expensive,
especially fer an old f*rt like me. I worked for NASA in the past and the quality of the test equipment is second to none ( hint hint) You can always ask here for opinions before shelling out $$$ on something that may not be suitable.
jb

10th Dec 2015, 7:12 am	#1
ct92404 Pentode Join Date: Sep 2015 Location: San Bernardino, California, USA. Posts: 101	My first restoration project. Emerson Model 503. Hi group, I've been here for a little while now. First of all, I'm actually in the United States but I found this website a short time ago on a Google search and I really became hooked. I especially enjoy reading the posts where someone has taken an antique radio or television that was neglected and falling apart and looked totally hopeless, and managed to restore it and get it working again. It's truly amazing what some of you guys have been able to do! I've always been fascinated with old vacuum tube radios. They were well before my time, but I love antique electrical and mechanical things in general. A couple of weeks ago, I bought an Emerson Model 503 tube radio from an antique shop. It was in REALLY sad shape. The case is made out of wood, and there were chips and gouges in many different areas. It was also completely filthy, and was missing the antenna coil and rear cover. Still, I fell in love with this thing because it just looked incredibly old. Also, even though it was in bad condition, it did seem to have all the parts in the chassis, and I felt that I might be able to fix it. http://i45.photobucket.com/albums/f8...psuie9qopq.jpg http://i45.photobucket.com/albums/f8...psygltpsaq.jpg I looked up this radio, and I found out that this model was made in 1946! I have a collection of a few other antique tube radios and this is now the oldest one I have. But in order to save it, it was going to need a LOT of work. It was a major project. I've never tried to fix an antique to this degree. I've only replaced filter capacitors before that that's about the most I've done. When I plugged in the radio and switched it on, it did power up and the tubes lit up. But of course it didn't work, and there was a very loud hum. I started by taking the chassis out and thoroughly cleaning it and the wooden case. The chassis had a little bit of rust and probably decades of dust and grime on it. I then replaced the electrolytic filter capacitor. That got rid of the hum. But of course the radio still couldn't pick up any signals because it didn't have an antenna coil. I had to make one. I've never made a coil for an AM radio like this before, so I really wasn't sure exactly what gauge wire to use, what length or how many turns, etc. I had to experiment with many different coils I made. But finally I made a long coil with 28 gauge magnet wire (American Wire Gauge, I'm not sure how you guys categorize it). That worked, and now the radio has great reception. The next step was to restore the wood case. That was a HUGE amount of work too. I patched up the areas that had chips with wood putty, and some corners also had big gouges where the corners had to be reformed. Then I sanded it, filled more with putty, sanded again to make it as nice and smooth as I could. Then I painted it. Because I had to use putty to repair the case, I couldn't use varnish. So I used paint that was as close to the original color as I could get. It's not perfect, but I think the radio sure looks a HECK of a lot better than it did! http://i45.photobucket.com/albums/f8...psjz76ztby.jpg http://i45.photobucket.com/albums/f8...psucxsibhz.jpg http://i45.photobucket.com/albums/f8...psctkn7inq.jpg I decided to make the rear cover smaller just so plenty of air could get inside to keep the radio cool. I might make a different cover later, but for now I think it's okay. You can see the homemade antenna coil I made. The radio works VERY well now. I can pick up AM stations very loud and clear...in fact, it actually sounds better than some of my other radios which I have never had to fix! I'm really happy with how it turned out. There is one part in the front where the paint or varnish came off and so I'll have to see about repainting the front later. You might be able to see that in the bottom left corner. But overall, my first restoration project seemed to go well! Last edited by ct92404; 10th Dec 2015 at 7:17 am.

10th Dec 2015, 7:32 am	#2
joebog1 Banned Join Date: Jun 2015 Location: Mareeba, North Queensland, Australia Posts: 2,704	Re: My first restoration project I agree with that !!! NICE job regards Joe

10th Dec 2015, 9:27 am	#3
raditechman Heptode Join Date: Feb 2007 Location: West London, UK. Posts: 867	Re: My first restoration project Well done. I hope you checked the coupling capacitor on grid of V4 the audio output tube.(50L6GT?) This is fed from the plate of the preceding tube and if it goes leaky puts +ve on the grid.(not healthy!) I think in your set it is C13 and .02mfd. This is sometime called "that capacitor" on this forum. It is important to check and replace. John

10th Dec 2015, 12:24 pm	#4
Peter.N. Dekatron Join Date: Jul 2008 Location: Charmouth, Dorset, UK. Posts: 3,601	Re: My first restoration project. Emerson Model 503. Nice restoration that. I have an affinity for pre war USA radios as we had quite a lot over here in the '50s fitted with resistive 'line cord' to 'lose' the other 110 volts. They were mostly very compact, much smaller than most UK radio's of the time. Peter

11th Dec 2015, 1:33 am	#5
ct92404 Pentode Join Date: Sep 2015 Location: San Bernardino, California, USA. Posts: 101	Re: My first restoration project. Emerson Model 503. Thanks for the replies everyone! And no, John, I did NOT check that capacitor...I didn't even know about it! I'm still pretty new to all this. I do have a little experience with electronics, but I'm still new to working on these old tube radios and I have a lot to learn. I will look for that capacitor and check it. Thanks for the advice! So could it actually cause damage to the tube if it is leaky? - Chris

11th Dec 2015, 2:50 am	#6
joebog1 Banned Join Date: Jun 2015 Location: Mareeba, North Queensland, Australia Posts: 2,704	Re: My first restoration project. Emerson Model 503. Its one of "those" capacitors !!! If it leaks it will reduce/change/apply a different DC potential to the grid. That will cause the valve to cunduct too much current. Normally the distortion would give an experienced person the hint, that something was not well. As you are just beginning on one of the best hobbies you will ever have, its one of the best places to start. If it needs replacing its cents only, but at worst it could fry both the valve AND the output transformer, and perhaps because of the extra large current draw, take out the rectifier, AND the mains transformer. This is of course, WORST scenario. BUT you will find it fun to do. BE VERY careful of high voltages!!!!! Death is permanent!! I think first you will need find the circuit diagram that we can all look to. That way you will have many questions asked by us, as well as you asking many questions of us "why" ? Best regards Joe

11th Dec 2015, 4:07 am	#7
ct92404 Pentode Join Date: Sep 2015 Location: San Bernardino, California, USA. Posts: 101	Re: My first restoration project. Emerson Model 503. Yikes, okay I'm definitely going to look for that capacitor then. And it's called the "coupling capacitor"? I looked it up online and coupling capacitors are used to pass alternating current, while blocking DC, is that right? Now that we're talking about this, what would a radio sound like if that coupling capacitor was going bad? I have another antique tube radio, a Zenith model F508L radio, that seems like it might have some kind of distortion going on. It's just a small plastic desktop radio. It works well, but I have noticed that it sounds a little "crackly" if that makes any sense. There's like a faint high frequency hissing in the background. I always thought that was just normal for some old tube radios, but could a capacitor be a problem?

11th Dec 2015, 5:52 am	#8
joebog1 Banned Join Date: Jun 2015 Location: Mareeba, North Queensland, Australia Posts: 2,704	Re: My first restoration project. Emerson Model 503. May very well be !! You really need a reasonable multimeter, AND read the manual for it. A modern digital is OK, its NOT as nice as an old Simpson or similar, a VTVM being the best for valves. Modern digital stuff keeps counting and counting and counting, UNLESS the voltage/signal/measurement point is as stable as the rock. An analogue meter moves as much as the digital does, BUT its much easier to read "about" 10.5 volts rather than 10.723546 10.4678465 10. 41482489 etc etc. Joe I read LOTS of adds from USA about ex-military, NASA disposal stuff that I positively DROOL over. BUT added to USA post, and the weight of "old decently built" stuff its prohibitively expensive, especially fer an old f*rt like me. I worked for NASA in the past and the quality of the test equipment is second to none ( hint hint) You can always ask here for opinions before shelling out $$$ on something that may not be suitable. jb