Old Emerson tube radio

[bluto]

I got this the other day. The person that gave it to me said they plugged it in and got nothing. I chastised them for doing that. I am not sure what the model is. The part that said that on the sticker seems to have worn off. Initial inspection reveals that the 'ballast tube' (2ur-224) is hanging by a thread. Someone apparently thought it needed a 1 before the 2ur and drew it on with a pink pencil. I really love the foil shield replacement on the far left tube too. The next thing that I see is that the set has previously been worked over with the addition of another capacitor that is apparently connected in line with the originals (which were probably bad). There is also a suspect looking diode (marked ELM .56) that doesn't appear to be OEM either. The lead connecting it to the tube socket was poorly soldered and has come loose (but still wrapped around the other lead - so basically intermittent).

I have restored one other old radio previously be replacing all the caps and a bad speaker. So I am hoping to get this one going too.

Questions:

How can I find the exact model number? (it looks pretty close to this one http://www.wkinsler.com/radios/emerson.html)
Where can I get a replacement 2ur-224 ballast tube? According to this it crosses to a L49B.
Any tips on getting it going again? (besides using the dim bulb test and replacing all of the wax capacitors with ceramics and probably that hacked in replacement with 'lytics too)

[bluto]

Re: Old Emerson tube radio

Further study reveals that the serial number could contain the model number. AM118, but it is not listed here: http://www.nostalgiaair.org/Resources/131/T0000131.htm

[Krankshaft]

Re: Old Emerson tube radio

The part number 2UR-224 is an Emerson part number for a L49B ballast tube.

These guys should have it:

http://www.oldradioparts.com/

Click the radio parts link then ballast tubes search for an L49B.

Check this site out for help with tube gear:

http://www.antiqueradios.com/forums/

That's where I used to go when I restored tube radios.

When you get your hands on the ballast tube be sure to replace all of the paper and electrolytic caps in the set then either power the radio up with a light bulb in series with the power cord or slowly bring up the line voltage with a variac.

A bulb will glow brightly if there is a fault like a short and save the set from damage. With a variac you have to be more observant as you turn up the voltage.

[PCBONEZ]

Re: Old Emerson tube radio

Try 118

One of the Patents is here:
http://ip.com/patent/US1511015
Says 1924 [It's got to be newer than the patents printed on it.]

118 says pre Oct 1936
.

[PCBONEZ]

Re: Old Emerson tube radio

B131 ??
http://www.radiomuseum.org/r/emerson_b131.html
.

[bluto]

Re: Old Emerson tube radio

I think you nailed it with B131. I pulled the schematic from nostalgia air and everything seems to match up. It threw me for a loop for a few minutes because with the exception of '43' and '75', the tubes in the schematic matched those in the radio. But then I looked a little further and figured out the '43' and '75' were succeeded by '25L6' and '6Q7' which is what was actually in the radio. I'll start ordering some parts and give an update on the progress.

Many thanks

[kc8adu]

Re: Old Emerson tube radio

maybe go to a 50l6 and 35z5 and delete the ballast?
just leave it there for looks.at least its not a "curtain burner" with resistance wire in the line cord!

[bluto]

Re: Old Emerson tube radio

Tell me more. I get that the ballast tube is just a big resistor. One tip I read suggesed by bypassing it with an appropriatly sized wirewound resistor under the chassis. What you are saying is that I could replace two of the other tubes and the do away with the ballast completely (bypass it)? Would I need to do any other modifications?

[bluto]

Re: Old Emerson tube radio

I started working on the radio. Replaced the caps that I had in stock and ordered the rest. The ballast tube seems ok when checking with an ohm meter. tried powering it up with a variac and a 100w light bulb inline. Nothing nada not even a twitch. I looked at the schematic and it appears that all of the heater circuits of the tubes are in series. So like cheap christmas lights, one going out will kill them all. Not that the radio can work with a bad tube, but this would explain why I did not see any of the tubes glow or feel any heat on the ballast tube.

Also I read this this that says on some radios, due to cost cutting, the dial lamp burning out would cause a tube to fail shortly if the dial lamp was not replaced immediately. This bears noting because my dial lamp is burned out. More are on the way.

So I guess I need to see which tube has an open heater circuit and replace it? Or find a tube tester

[b700029]

Re: Old Emerson tube radio

From that link....

Placing the switch in the ground side of the line saved them a terminal lug.

Imagine what cheap PC PSUs would be like if it weren't for agencies like UL today

Testing heater continuity can be done with a multimeter.

[KeriJane]

Re: Old Emerson tube radio

So I guess I need to see which tube has an open heater circuit and replace it? Or find a tube tester

If you're anywhere near Chicago, I've an old tube tester over here....

[ratdude747]

Re: Old Emerson tube radio

iirc he is closer to st. louis.

[bluto]

Re: Old Emerson tube radio

From that link....

Imagine what cheap PC PSUs would be like if it weren't for agencies like UL today

I saw that too. It seems this set was one of the ones the link is referring to. Thankfully whom ever worked on this set previously had the sense to connect the neural side of the plug to the lug that is tied to the chassis. I read somewhere else that Emerson was the low cost brand, I guess this proves it.

Thanks for the offer on the tube tester, but I live about 300 miles south of Chicago.

[bluto]

Re: Old Emerson tube radio

Ok, hopefully my last question... I think I found the bad tube. The 25L6-GT tube is open across the heater circuit. However, the schematic calls for a '43' tube. Looking here: http://www.radiomuseum.org/tubes/tube_25l6gt.html , it seems that the this was a successor to the 43. Should I get a 43 or a 25L6-GT as a replacement? Or does it matter?

[dood]

Re: Old Emerson tube radio

I might have a 43 in a box up in the attic...

[bluto]

Re: Old Emerson tube radio

Well my order from AES finally came in... And I am happy to report that the old Emerson is back up and running. The new 25L6 brought it back to life. I then did what I think of as a 'sympathetic' restoration. In addition to the 25L6, I replaced the cord & plug, dial cover, and all of the wax capacitors. I put a new logo sticker over the faded old one on the front. A little bit of cleaning and waxing of the cabinet was done too. I also made a new back cover that is historically informed when compared to the monstrosity that it had that was cut out a piece of press board from the back of some old TV. I still need to get a new ballast tube and a tube shield for the 6A7 (oldradioparts.com has them - Thanks Krankshaft!). Thanks everyone for all the helpful replies.

[Krankshaft]

Re: Old Emerson tube radio

Nice job! That Masonite back panel looks factory.

How did you cut those vent holes so cleanly with a router?

I can't get over that tube shield I keep thinking it's so the government can't read it's mind .

[PCBONEZ]

Re: Old Emerson tube radio

Good job!

[bluto]

Re: Old Emerson tube radio

Thanks. I started the vent holes by drilling two 1 1/2" holes for each cutout with a forstner bit on the drill press. I then used a router to connect the dots. By clamping a piece of wood (straight edge) on the cut line and using a pattern cutting bit, I was able to get a nice clean, straight cut. I found a picture on radiomuseum showing what the back was supposed to look like. Before I found that, I was leaning towards no back at all. At least now it is somewhat accurate to the original.