erla and what is it?
 

Hi Folks,

A friend gave me this old radio. The dial says ERLA and the chassis says 46A 4800E. Label says 46ACE-140-E.

I see the unit is licensed by Hazeltine Corp. (on the label)

Help me out so I can find a Schematic for this nice little radio.

http://www.nemontel.net/~scooters/erla/FrontDial.jpg

http://www.nemontel.net/~scooters/erla/Front.jpg

http://www.nemontel.net/~scooters/erla/Lable.jpg

http://www.nemontel.net/~scooters/er...s46A_4800E.jpg

http://www.nemontel.net/~scooters/erla/ChassisClose.jpg

http://www.nemontel.net/~scooters/erla/JensonSpk.jpg

:banana:

Thanks for the help,
Buzz:music:

Looks to be a mid Thirties console...

Erla was an old radio company from the twenties that blended into Sentinel in the thirties. I believe your set's schematic is the following indicated as model 46A in the Sentinel listing from "pre-1938." Your sticker on the radio back says made in plant "S" which tastes like Sentinel. :yes: It's an 8-tube set with tuning eye, and from what I can see on your pictures, the tube lineup looks right compared to the tube layout on the schematic. Have a look and compare to your radio.

http://www.nostalgiaair.org/PagesByM...7/M0018207.pdf

Sentinel
 

Thanks guys,

It does look real close. I wonder why there "ERLA" name isn't listed in the Schematic database web sites?

This should get me started soon as I get done with two other little projects.

The case sure is well built and sturdy. The speaker looks like brand new. Do you suppose it's been replaced?

Buzz :music:

The diagram shows a three band radio when there are only two bands on the dial. As for the speaker there seem to be too many wires going to it. Four wires to the field coil? If so, that would mean two field coils, like a hum bucking coil. Unlikely an exact replacement would be available any time in the recent past.

An interesting puzzle. What does it say on the green tag?

4 wires going to the speaker (and output transformer peeking out from the bottom). That would jive with what the schematic shows. One from the rect to the speaker field, one coming from the speaker field back to the set (and the center tap of the OPT) and the 2 plate leads. The wire between the speaker cable and green tag appears is just hanging there, not connected to the speaker. I'd suspect that was the antenna lead, with the black wire (green tag) being ground.

Nice looking cabinet. once you get it working and refinish it you will have a real show room piece.

Tom C.

bucky humbucky
 

Hi guys and thanks for all the help,

I count the 4 wires on the schematic too. And to satisfy Bob's statement about a Guitar Humbucker, the drawing shows the "bucking Coil" right in the speaker area.

I haven't opened it up yet to look but I see, on the schematic, the 12 and 16 mfd caps in the rectifier Ckt. Those might be the type housed in a Bakelite tube. (?) As Banderson shows in his famous videos on U-Doob. That's Cool.. I'll have to find some wax to re-do those correctly as he shows.

Buzz:music:

Look at pics 4 and 5. The aluminum cylinders between the power transformer and tuning cap are the filter caps. the 16uF minus goes directly to ground, the 12uF does not. (look for insulating rings around the bottom)

That may be the newest set I've seen with the ERLA name. I believe this was "brand-engineered" and likely available under a few aliases. The shape of that dial shows up on a few other minor brands from the late 30s.

I like it!

I think you'll be well-pleased w/it when you get it percolatin' again...(grin)

3 band radio
 

It's the Weekend!...

I was looking at the drawing and the dial ... 3 band? If you look just around the area of the ERLA name and in the same yellow ink..you'll see the 5.8 to 18.1 mhz band.:scratch2:

Buzz :music:

One of the posts above said that the wiring diagram that I pointed out shows a three-band radio, but your dial shows two bands. The diagram is the closest one I found to your radio. Yours is probably a variant where they eliminated the less interesting first short wave band.

3 bands..
 

Reece.. if you look close to the dial picture, the radio does have 3 bands.. as mentioned in my last post.

Buzz:music:

Hi! ERLA stands for Electrical Research Labs. They were a radio mfg. located in Chicago. Schematics can be found on Nostalgia Air under that name. The reason I know this is that I just acquired a 1930's ERLA cathedral yesterday. Interestingly, it has a Hammond clock mounted within the area of the speaker cone making it one of the first clock-radios!!

Antenna
 

Question for you that might have seen this model.

I've been getting back with all my "started" radios for restoration. This ERLA upright is on the bench. As I was removing the chassis I noticed.. hay.. no Antenna!.. There's two leads coming out the back of the chassis and hanging down below the board that the Chassis was mounted to. Grabbing the flashlight, I could see were there's a mark on the underside of this board where possibly the Antenna could have lived. Here's a pic looking up at the bottom of the Chassis mounting board.:

http://www.rsgpianoservice.com/file/...tennaArea1.jpg

You can see the 3 holes for the chassis mounting screws and over to the right what looks like a large slot I presume is for the speaker wires (5) and the power cord. You can see the "band" from left to right where the antenna could have been.
I thought of buying a wave magnet or some such antenna but finding out just what was there would be interesting. I could also build one using a board form of the appropriate dimension and winding a coil on.

But I'd like to find out what is "original stock" for this radio.

Looking at the schematic, this radio did not use a tuned loop antenna. The antenna coils are already in the radio, part of the circuit, under the chassis. A loop would usually substitute for an antenna coil and eliminate the chassis antenna coil. This radio would use a conventional long wire antenna and a ground. The holes in the cabinet might possibly be for some other model chassis that would use this same cabinet and could take a rotatable loop; however, loops like that weren't common until a bit later. It is possible to staple a wire just inside the perimeter of the rear of the cabinet, and connect one end to the antenna lead, but it's not really a loop. It would probably work OK but not as well as 10 or 15 feet of wire inside the house or a real outdoor long wire antenna.

Thats one very fine radio...a real keeper and I notice that little Denmark made its 'fingerprints' on the America radio-industry in these early radio-dayes...

Peter L. Jensen dedicated his life to innovation and today’s Jensen® musical instrument speakers continue the essence of that innovation. Peter L. Jensen was born in 1886 in Denmark and came to America in 1909. He was instrumental in the development of the "Magnavox", the first loudspeaker. Magnavox speakers were predominantly used for public address systems and were first used in 1919 to amplify President Woodrow Wilson's speech in San Diego. Peter Jensen later founded Jensen® Radio Manufacturing Company and produced speakers for both military use and radios.

In the mid-1940’s Leo Fender developed one of the first guitar amplifiers and chose Jensen® speakers for their excellent tone. Throughout the 1940’s, 1950’s and most of the 1960’s, Fender®, Ampeg®, Gibson® and all the other major amplifier companies used Jensen® musical instrument speakers until Jensen® stopped making them in the late 1960’s.

In the late 1990’s, under a licensing agreement, SICA Altoparlanti, an Italian speaker manufacturer, commenced production of the legendary Jensen® speakers. These Jensen® reissues are made to the same specifications as the original Jensen® speakers used by Leo Fender and others.

The Jensen® name is synonymous with classic vintage tone, and is the pioneer in modern state-of-the-art speakers today.

Ant
 

Thanks,

Looking at the inside of the Chassis I don't see any loop antennas. The antenna switch (see the schematic listed in one of the above posts) has one of these wires that stick out the back of the chassis going to it.. It switches to one of the 4 bands tank circuit. :

http://www.rsgpianoservice.com/file/UnderA.jpg

http://www.rsgpianoservice.com/file/ChassisDust.jpg

The lower photo shows the two leads coming out. They were hanging down in close proximity to the "band" that can be seen under the support board for the chassis. So, I'm thinking there's must have been some kind of internal cabinet antenna Reese.

That's interesting History for that speaker, Tube mania. It sure is a nice and clean speaker. I'm going to remove it from the grill mounting for inspection. Then remove the mounting board in prep for some refinishing.

Got to buy a couple of 16mfd ecaps @ 450 or so WV too. Beats spending my money at the Bar watching football and looking at the Gals.. er.. oh.. nope.. that's wrong.. :D

Buzz:scratch2:

There are no loop antennas in the chassis. There are antenna coils. They are some of the coils with the trimmers on them. If you look at the pages of the schematic, these antenna coils are identified on the drawing of the underside of the chassis. Before radios had loops they had antenna coils. If you think of a typical AA5 radio with a loop antenna, it doesn't have an antenna coil under the chassis but does have an oscillator coil under there. The loop antenna takes the place of an antenna coil.

Mo Powera
 

Thanks Folks,

Reese posted the link to the schematic for this radio in one of his posting (above) and it's real accurate!

After I got some of the Dust balls out I noticed a little funny looking round deal-e-O!.. It's a durn battery!.. Use for biasing the First Audio/Detector Tube (75).. and hooked to the variable arm of the Volume control pot... That's neat!:banana:

What should I use to replace this little single cell battery with? It's 1.5 volts and has a part number of 1928..?.. No, I didn't measure this one yet.. I bet it's dead as a door Nail! Nice little holder too.

It's a little hard to see in my picture. It's just South of the Diagonally mounted Blue Ecap and it's on the terminal strip. The holding clip is to the left of the actual round battery.:D

Buzz

Watch batteries work well I hear. I have a Grunow tele-dial table set awaiting my attention that has one of those dias cells as well.

There was a good article in ARC (antique radio clasified) a while back on those bias cells that you may want to read.

You'll find a lot of ideas about how to work around these bias cells. They were used in some radios from around 1936 to just before the war, and then pretty much disappeared. They were a good idea for providing a steady negative grid bias, but they can eventually wear out. Some try to rejuvinate them by injecting water, others use a watch cell as Tom C. noted: you'd dig the guts out of the old cell and modify it so that the watch cell could be used in the old holder, with the negative terminal towards the 75 tube grid. Yet another way that's easier and will probably work fine for you is to just replace the 1 meg resistor in that line to the grid with a 10 meg from grid to ground and leave the old cell in there for looks but disconnected.

A grid will collect electrons and bias itself negative but unless there's a way to bleed some of them off it will become too negative and tend to cut off the tube or cause erratic action. The high value resistor will bleed off the excess. This is not the most sophisticated way to get grid bias but it should get the job done.