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Norwegian: Elektrisk Bureau 1920ish CB

Started by dsk, March 01, 2013, 02:54:27 PM

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dsk

Not sure of the model but 1921-1925 should be close.
dsk

dsk

More documentation:
Reverse dial for Oslo!


dsk

dsk

I have been working a bit an the diagram, and the only who actually is different is the terminals on my wall phone.


Not sure about the exact date on this, but the dial was a pretty early version. My guess 1921 based on later dials had enameled dial face, this looks like paper and colloid on a metal palate. I had to make a new one, and the I made it as a normal dial, not Oslo (reverce). The last pulse was long so then I know it has been on Frogner exchange in Kristiania (Oslo)
I modified it, adjusted the pulse length to as long as possible, but it is still short. Dial speed is not adjusted so it goes on about 13 pps. This works fine on my old xsx PAX.


I also had to give the phone some paint to look a little better.


Now I miss the right handset.


dsk









AE_Collector


dsk

Painting is difficult, but nowI guess I have finished this one.
I had to make a new number ring under the dial, the dial was not easy to tune, but it is dialing OK now, and the phone looks OK too. It sounds pretty well, it is a sidetone booster set, and I had to put in a replacement capsule at the transmitter, that makes the sound strong and clear.  Look at the screw on the top of the dial center "ring". Maybe that may help identify the dial?

dsk

dsk

Since I have learned more about dials lately, but this is actually a BTMC 7001E

dsk

dsk

#6
As mentioned, I modified it and stretched the break timing as much as possible and the result was great! better than what I did believe was possible.


10.41 pps or 4.11% faster than nominal speed, and within limits of OK for a new dial.
Percentage of break 64.01 witch is 6.64% more than US standard and 3.98% under the UK standard, and in both cases less than 7% off witch is the limit for a new dial.