Monday, March 23, 2009

Rikstelefonen Type E.B. 21 Telephone

Some time ago, one of my relatives brought this wall-mount telephone back from Norway (it had been in the Oslo apartment of my step-mother's parents from the mid 40's until 1980), and he asked me to take a look at it to see if it could be made to work on the American phone network. (He'd be happy just to hang it on his wall, even in a non-working state, but a working phone would be so much cooler!)

The only identifying labels on the telephone are "Rikstelefonen" on the front (just below the dial), and a sticker on the back panel that states, "Type E.B. 21". Given that the phone came from Norway, I'm assuming that "E.B." stands for "Elektrisk Bureau," the Norwegian telephone manufacturer.

Inside the telephone was a dangling wire (with a spade connector) from the dial assembly and a nine-terminal terminal strip. Before I tested the phone, I would first need to reattach this wire. But to what? The dangling wire clearly needed to be attached to the terminal strip, but the terminals were labeled with cryptic markings such as La, EK, Lb, ET, T, and M. Which terminal took the wire, and which terminals should I connect the Telco line to? I had no idea.

(The large light-grey boxy thing with 2 terminals on the back panel is a 2uF capacitor)

After much fruitless searching on the web for information about the phone, I finally bit the bullet and drew a schematic by tracing out the wiring. From that exercise, I discovered that the dangling wire was attached to the dial make-break switch. Clearly it needed to be in series with the telephone line (so that it could pulse the loop-current during dialing). But...I still didn't know which terminal should it go to.

A couple of members of the "Telephone Collector's International" mail-list helped put me on the right track. I'd noticed that two terminals, La and EK, were jumpered together, and that one side of the ringer attached to the EK terminal. Someone mentioned that often the ringer was attached to a ground terminal, and that, for "straight-line ringing" it would be jumpered to one side of the line.

This correlated well with what I saw. 'EK' must be the ground terminal, and 'La'...the 'a' side of the line!

So if La was one side of the telco line, then Lb must be the other side. But nothing was attached to this terminal. Hmmm...probably the dangling wire had been attached to the Lb terminal (along with one of the telco's line wires), and it had fallen off sometime after the phone was removed from service -- the Lb screw had been loosened (I assume to remove the Telco line), but not subsequently retightened.

I connected the dangling wire to Lb, then ran wires from La and Lb to my telephone line. Now was the moment of truth! I took the handset off-hook, and...dialtone!. I dialed my number from another line, and the ringer rang! Upon answering, I realized I could both speak and hear, so the handset was working (although I didn't check levels). And finally, I dialed another line using the (weirdly numbered) dial, and the other phone rang. Everything worked: handset, ringer, and dial!

So the job's almost done, and then I'll return the phone to my relative. But first, I need to replace the handset cord (it's severely frayed), and get a line cord with a modular plug on the end. But once that's done, "Rikstelefonen Type E.B. 21" should be ready for prime time.

(A quick note about the dial. It's numbered backwards from the American dial (with the exception of 0), so one way to dial a number in the U.S. is to count "finger holes" counter-clockwise, rather than use the printed numbers.)
(Oh, those Norwegians!)

And here's the schematic that I drew. I believe it's correct -- I checked it against the schematic I scribbled into my lab notebook, but it hasn't been rechecked against the actual wiring. So use at your own risk!
(Click on image to enlarge.)

Some additional information just received via the "Telephone Collector's International" mailing list...

From Roger Conklin:
According to the book Telefonappater i Norge 1880-2000 page 62, this telephone was manufactured by Elektrisk Bureau from 1921-1924. This book was published (in Norwegian) by Norsk Telemuseum, Oslo in 2000. It describes the telephones in that museum which my wife and I had the opportunity to visit several years ago. I bought a copy of this book at the museum during that visit.
And here's a schematic from a different Elektrisk Bureau phone (original photo taken by Harry Smith and posted here on the TCI photo site. I've used Photoshop to do some keystone correction of Harry's photo, and I've also added some annotation to clarify some of the original schematic symbols).
(Click on image to enlarge.)

Note the differences between his phone and mine: The La to EK jumper is not done on his terminal block (as it is in my phone), but instead it appears to be done in the plug (if I'm interpreting the round symbol on his schematic correctly -- but perhaps that's the wall terminal? Don't know...). (Per Steph Kerman on the TCI reflector, wall-mounted phones (such as the one I'm working on) typically had this strapping done within the phone itself, while desk-top units had the strap inserted at the wall terminals.)

Also, in my phone the two switches within the dial mechanism are not electrically isolated (as is implied by Harry's schematic), but they share a connection (the Brown wire shown in my schematic connects to both switches).

But other than that, the two schematics are quite similar (except for wire color differences).

Thursday, March 12, 2009

Rogue's Gallery

Some of the gang (from a BBQ at my house after the last De Anza swapmeet of 2007 (October '07)):

Joe, N6DVD; Vlad (sitting), KB9OLM; Dick (standing), W1QG; and Denny, AE6C

(Sitting) Vlad, KB9OLM; Denny, AE6C; Bob, KX6K; Jon, K6JEK; Russ, NM6DX

Jon, K6JEK; Russ, NM6DX; Mark, W6NB

Les, WB6ORZ; Rich, WA6KNW; Rod, KQ6F

(Please ignore the small delay in getting these posted! - Jeff)

Saturday, March 7, 2009

Fireside 'Type A' Crystal Radio

Unbeknownst to me, last year my dad gave his cousin Ben a bottle of wine that I'd made (Olcese Family Reserve -- I named it after my Great-great grandmother's married name (she came over from Italy to California in the 1860's)). Not much later I received a box in the mail from Ben with a nice thank you note (for the wine) and this radio. Headphones were included, too!

Apparently it had been sitting around his house for some time, andI guess he must have learned that I like old radios. Anyway -- it was an unexpected gift, and I very much appreciate him sending it to me.

I immediately hooked it up to a long wire, put on the headphones, worked!!!

It's a Fireside (Type A) crystal radio. I haven't been able to discover any information about it. But here are some more pictures...

Simplicity itself, eh?

(By the way, it should be fairly obvious that the radio has had some mods/repairs made to it sometime during its life. The insulated white wire is one giveaway, as is the shoulder screw holding the detector's bracket to the front panel (the detector under the round metal cover at the left.)

And another clue is the replacement of the cat-whisker with a modern diode (I don't know if it's a silicon diode or germanium) -- you can still see the crystal embedded in a blob of solder, but now there's a diode connected from the blob to the other screw.

LTV G133F Receiver (Collins 51S-1)

(Click on photo to enlarge.)

I picked up this receiver some number of years ago, pre-Ebay, on It's actually a Collins 51S-1 Receiver that had been repackaged by LTV. I have to admit, it looks VERY cool.

In addition to the strange knobs, LTV also added a plastic front panel, painted matte black, with engraved labels for the controls. LTV embedded lamps in the plastic, and when the receiver is on, the engraving actually lights up (as shown below). How cool is that?

Real Radios really do glow in the dark!

(I'm not exactly sure what the "AM BFO" control does (lower left-hand corner of the receiver) -- it's possible that this function doesn't even work on this receiver, as I've had no luck getting it to do anything. But what the heck -- the receiver is pretty darn cool anyway!)

By the way -- I'm not exactly sure what the receiver was used for. Someone mentioned that it was used on spy planes, but I don't know what the actual story really is...

The Morrow Twins -- MB-6 and MB-565

Back in the late 60's, when I first became interested in ham radio while in junior high-school, one of my parents' friends who had been a ham (Hal Schell -- ex-K6IGQ ("Idiot Gone Quacky")) gave me an old Morrow Converter (5BRN) and IF unit (FTR) that he had used mobile once-upon-a-time.

A few years later, while in high school, I traded a BC-652 receiver (that Hal had also given me) for a Morrow MB-560 transmitter with another high-school ham (Sandy, WB6FHG). The Morrow set made a cute, incredibly compact pair (compared to my station at the time, which was a Hammarlund HQ-129X and Heathkit TX-1 Apache with SB-10 Sideband adapter ), but I rarely had the receiver on the air and never the transmitter -- didn't have a power supply.

That was more than 30 years ago -- in the intervening years those original Morrow pieces went their separate ways (I no longer recall where), but I continued to maintain a fondness for them.

A couple of years ago another friend offered me a handsome receiver and transmitter pair consisting of the Morrow MB-6 Receiver and the Morrow MB-565 Transmitter (see photo below). Although the knob layout is similar to earlier models, such as the MB-5 and the MB-560, if you're familiar with Morrow radios you'll immediately spot a few significant differences: the knobs a plastic, rather than metal, the dial is a drum, rather than a slide-rule, and the meter faces have a black background, rather than the usual yellow background.

OK, so the knobs are plastic, but to be honest, this is better than the metal knobs -- whenever I've come across metal knobs on a Morrow the knobs have always been absolutely filthy: grungy and oxidized. The plastic knobs, although looking a bit cheap, do clean up easiy and are, in my opinion, a nice improvement.

Here are some pix of a Morrow MBR-5 Receiver and an MB-560 Transmitter (that I sold on Ebay some time ago) for comparison purposes:

I have to admit, I do like the slide-rule dial of these earlier radios better than the drum, but I really dislike the metal knobs. If you click on the picture (to enlarge it), you might get an idea of what the knob oxidation looks like (it's on the sides of some of the transmitter's knobs).

Here's what the MBR-5 looks like inside. The MB-6 is similar. Pretty nice construction, eh?

* * * * * * * * * * * * * * * *

To power my MB-6 and MB-565, I modified an old Galaxy power supply that I had lying around to supply the appropriate voltages for the two radios. I also made a little external box to switch the Transmitter's B+ on and off with PTT.

I've had this pair on the air -- usually on the local (Northern California) AM net on Saturday mornings (which is why there's a crystal for 3870 KHz installed in the transmitter). To get a bit more power out, I use a linear by running the MB-565 output through an external RF power attenuator before feeding it to my AL-811 linear. The attenuator cuts the Morrow's output of 25 watts down to a level (about 10 watts) that gives me about 100 watts carrier output from the AL-811. This is pushing the three 811A tubes in the linear a bit harder than they should be pushed (they're only rated at 45 watts plate dissipation CCS, 65 watts ICAS, and the linear's total plate dissipation is about 420 watts (1.6KV * 260 mA), which is about 140 watts per tube), but it seems to work fine, and the tubes only have a very dull-red glow when I'm doing this.

Shack Pix!

I always like looking at shack pictures. Curious about mine? Here's the latest configuration!

How many radios can you identify?

Here's a better view (albeit leaning a bit!) of some of the boatanchors...

And a rack of higher-end receivers...

And of course, no shack would be complete without a lab (this shot was taken a few years earlier). Most of this equipment was broken when I purchased it, and I repaired it...

(Click on images to enlarge!)