Type 51 Ericsson

[AL_as_needed]

My first Ericsson. I picked it up over the weekend for all of 8$. Fairly clean, no major damage. The dial sounds like a coffee grinder though, can't have everything.

[unbeldi]

My first Ericsson. I picked it up over the weekend for all of 8$. Fairly clean, no major damage. The dial sounds like a coffee grinder though, can't have everything.

Perhaps you should empty the coffee beans.   

A little cleaning and oiling will go a long way...

I think the Type 1951 is a very nice set.  I think you got a great deal.

[Matilo Telephones]

Nice find and very good price.

A while ago I posted a step by step restoration report on the wall version of this model. http://www.classicrotaryphones.com/forum/index.php?topic=10641.0

In it you will find some info on servicing the dial. Please mind, that if you remove the finger wheel, to put back the bolt before you work on it. Under the finger wheel is a metal cap that houses the spring. It comes of really easily. Be really carefull.

[Russ Kirk]

I agree,  nice price!   

I have one of these and it is missing one foot.
Anyone have an extra to sell me?

[Matilo Telephones]

I have one for you, if you like.

By the way, is that number card window painted over? The studs protruding on the inside look white.

[AL_as_needed]

Perhaps you should empty the coffee beans.   

Dutch Roast?

The dial cleared up real quick after I brushed off the old dried grease from the gears and re-oiled the posts, nice rhythmic clicks as it runs the numbers. Matilo, your sight has been a HUGE help to me with working on the dial.

As to the number card holder, it is not pained. Someone at some point may have broken the tabs off that hold it into the phone. To fix it they seem to have wrapped paper (maybe an old number card) around what remaind of the tabs and stuffed it back together. I will leave it as is for now until I get a replacement. Still looks fine from the outside currently.

[Matilo Telephones]

Glad to hear that my site was of huge help. Thanks.

This type of dial does get very noisy. It also does help to wipe the governor cup with a piece of paper.

And after you have finished with servicing it, a day later it sounds even better. The oil has had the chance to creap in.

Those number card holders are prone to damage. Luckily the frame itself is still there. A replacement is hard to find.

[AL_as_needed]

A twist in the tale of the T-51.

So I hit a snag with the receiver and sent a PM to Matilo for some help. The receiver at first was very quiet. Dial tone and test tones could be made out but at very very low volume, too quiet to actually use the phone. Matilo suggested to check the phone itself with a known good handset (did this, phone was 100%). He also cited that a magnet gets weak within the receiver......hmmm.....

So some careful disassembly and a bit of cleaning later.....the receiver was suddenly reborn and working very well. A few test calls, sound quality was great! It looks like there was some grease that coated the magnets and the diaphragm when the unit was new. This had since dried out and basically glued the diaphragm down, eliminating the vibrations needed for sound.

Not sure if this will fix all similar receiver elements, might be worth a try if otherwise slated for the trash.

[Matilo Telephones]

Thanks, I will surely try that myself.

Do you know what that grease was for?

Any suggestions on how to close the cap again?

[AL_as_needed]

I took a pair a small pliers and bent out the crimp only part way, you can see it left small dents around the front of the cap. Once I was done, I bent the tabs back in a little and simply pushed it back onto the body of the unit. It should snap in place. The small dents however will remain, but once installed you cannot see the unit anyway.

If I had to guess, I would say that the grease was to prevent corrosion of the magnets or softened the movement of the diaphram? Not sure. An old wood phone owner may be able to offer more insight on that one as the design is similar.

[unbeldi]

I took a pair a small pliers and bent out the crimp only part way, you can see it left small dents around the front of the cap. Once I was done, I bent the tabs back in a little and simply pushed it back onto the body of the unit. It should snap in place. The small dents however will remain, but once installed you cannot see the unit anyway.

If I had to guess, I would say that the grease was to prevent corrosion of the magnets or softened the movement of the diaphram? Not sure. An old wood phone owner may be able to offer more insight on that one as the design is similar.

If anything, it may have been used in embedding the magnet coil wire, but I have not seen this before. It certainly was not for damping the diaphragm.  This would be too crude and an ever variable situation. The distance between magnet poles and diaphragm was an exactly controlled parameter and of prime importance for performance.  Grease has a tendency to crawl and seep, and soften and harden with temperature.

[AL_as_needed]

If anything, it may have been used in embedding the magnet coil wire, but I have not seen this before. It certainly was not for damping the diaphragm.  This would be too crude and an ever variable situation. The distance between magnet poles and diaphragm was an exactly controlled parameter and of prime importance for performance.  Grease has a tendency to crawl and seep, and soften and harden with temperature.

And with the handset sitting on the receiver most of the time since the 60s when new, it would make sense that it would creep down onto the diaphram, especially if it were in a sunny room. I wonder, if this is a common occurrence with these units?

[unbeldi]

It's a bit hard to make out the dark shades in the pictures, but your handset appears to be the later type that looks a lot like the Bell version, which is in turn quite similar to the WECo F1.

My elements are different.  Does the receiver have any dates or designations?  If it is an Ericsson type I would expect at least the Ericsson logo impressed.

I do prefer the original handset style that was a carry-over from the late 1940s and was apparently only on the early versions of the Type 1951.  It still had the old-style spit cup.

[Matilo Telephones]

And with the handset sitting on the receiver most of the time since the 60s when new, it would make sense that it would creep down onto the diaphram, especially if it were in a sunny room. I wonder, if this is a common occurrence with these units?

Well it is a common occurence for them to go weaker. But I Always took it that the magnets got weaker and not that accumulation of a fatty substance inhibited its working.
The design of this cap is not unique and the problem should occur on caps of other makers too, right.

And if I were to put a cap like that on the radiator for a week or so, with the diaphram up, the volume should improve, would it not? :-) Worth an experiment.

[Matilo Telephones]

It's a bit hard to make out the dark shades in the pictures, but your handset appears to be the later type that looks a lot like the Bell version, which is in turn quite similar to the WECo F1.

My elements are different.  Does the receiver have any dates or designations?  If it is an Ericsson type I would expect at least the Ericsson logo impressed.

I do prefer the original handset style that was a carry-over from the late 1940s and was apparently only on the early versions of the Type 1951.  It still had the old-style spit cup.

That 1947 handset was only used for a little while on the type 1951. Only a year or so. I haven't been able to establish when they changed it. PTT also has retrofitted the newer design on almost all the early phones, so to find one with its Original handset is rare. After restoring about 50 of them and still with 30 of them in my house at this time, I only have one with the Original handset.

The Ericsson "F1" handset has in most cases the logo on the underside of the handgrip. But there are versions too without the logo. The Ericsson handset has flat ends, where as the true F1's have pointy ends.

NSEM (Standard) made a real copy of the F1, just like BTMC and ATEA.

Does your Type 1951 have a production date on it, Karl?