News:

"The phone is a remarkably complex, simple device,
and very rarely ever needs repairs, once you fix them." - Dan/Panther

Main Menu

Mix & Genest ZBSA24 two-line

Started by countryman, September 23, 2022, 03:17:28 AM

Previous topic - Next topic

countryman

I just found this phone, or did it find me? It's a German ZBSA24, supposedly a two line model - not sure if for 2 separate office lines or one office line and one for an automated private system separate from the public network. The literature mentions that the German Post (RTV, Reichs-Telegraphen-Verwaltung at that time) discouraged the use of PABX and wanted to keep things separate.
However, the phone seems to connect itself to the a/b line "N" when the handset is lifted. Pushing the black button puts this line on hold, and the phone is connected to the other a/b pair "R".
The red button releases the black one and reverses to "N".

The phone looks complete so far, a capacitor and the second ringer would sit in the (missing) subset. All parts are marked Mix & Genest, the transmitter is dated 7/33.
As discussed in this thread, automatic phones were officially called ZBSA until ca. 1928, when the W28 was released. Then the model names just started with a W (Wählapparat, dial phone). This phone seems to be a later model 24, presumably 1933, telling from the transmitter, and also from the more modern, rather simplified version of the '24 handset. So it seems a bit unclear why it is still marked ZBSA, and whether it was an "official" or a private phone?
It has a Mix & Genest dial I have never seen before, and the numbers are arranged slightly different from any other German phone, too (3/4 on top).
The phone needs cords (came with a filthy plastic handset cord, not connected, and should work then.

countryman

some details

tubaman

Nice find.
I'm wondering if this is part of a Manager/Secretary type set, where this is the manager's half. When the handset is lifted it connects to the secretary (who may be transferring a call to it) or there is the option of the second private line which then shows the phone as busy to the secretary?

countryman

Thanks :)
That's hard to tell. Apparently many variations have been made. There is a very similar one in the erel.de collection. But it has a stack of switches also under the left (red) button which mine does not have. The provisions are there, but no switches, it only releases the black button with the function as described. I can't see any missing/cut/unsoldered wires in mine, so I assume it is original. But who knows.

dsk

The dial observation was interesting, I had to look at my older German phones and all had 4 on top, so what could be compared, and all my Elektrisk Bureau and Ericsson phones had 3/4 on top... except from one!   That was an Elektrisk Bureau dial made in between 1924 and 1928. (Those were not good and they just stopped making them)
Why did the companies make the different layout?  I just have to guess, dialing the right number with the ZBSA-11 is not easy, because the distance between the pretty narrow holes are small, and it is easy to get wrong number if you do not feel excactly how hard you hit the fingerstop, and relase the dial in the right position. The next had to be the ZBSA 24? You got a modern dial, much easier to use, and the only drawback was that you could be to quick between 2 digits.  That was solved on the dial used on the W48.
Then my question are what will make the rare dial of yours less good, or may it be another reason for just using the more common dial with 4 on top.  I took a look and it seems like a few others used that dial too, but this is not easy to tell.
Take a look down on this page: https://www.swiss-phones.ch/schweizer-telefone/telefone/telefone-1878-1930/

countryman

To make the confusion complete, the internals of this dial are very similar or even identical to that of the "Weltruf" Bakelite phone, which has the 4/5 on top  ???
Mix & Genest was one of the oldest German phone makers but was taken over by AEG (electrical equipment) 1920, then 1929 by Standard Electric, and was fully integrated into ITT 1934.
I'm not sure about the company's business during WWII, being an American owned operation? At first glance it seems their products did not catch on much, although they were innovative and of good quality. Maybe because the "official" buyers ignored them? But that's purely speculation. After '45, the production increased and M&G, and it's successor SEL, were major suppliers of the Bundespost with a new generation of products.

dsk

I am trying to get this one, and the dial could be close to yours, but is it the same?
This phone is made later than yours..but mounted in an other angle (rotated)?


countryman

#8
The phones in the links have the 4 in the top position, a Merk and (supposedly) a Siemens & Halske type. The wall phone in your picture is a Mix & Genest "Weltruf" wall model, same dial as the desk version in my link below. The mechanism inside looks similar, but the travel from the 1 to the fingerstop is longer on the phone discussed here! It has a mechanism to suppress one pulse in order to enforce a longer pause between two dialed digits. This requires a longer travel.
I'll have to open my "Weltruf" again, but I'm quite sure it does not have this feature. "Officially" it was introduced with the Siemens N38 dial type (1938).

countryman

Here's an update. I made new cords for the phone. A left-handed 4mm screw missed in the push button assembly. I could obtain one from China. Instead of using a subset, a modern 1µF capacitor is now connected right to the terminals, so the ringer works for the main line ("N", normal?). The "R" (request?) line also works, but would need an extra ringer. I just fitted test plugs, for which I have an adapter. When the original plug can't be obtained or never existed, like here, it will be OK I think.

Sergey Paganini

Hello, I repaired the same phone (restoration) for a collector a couple of months ago. With the second call (on the second line) there was the same problem. He was absent . I solved this problem simply by connecting one line through a 1 microfarad capacitor to one of the two coils of the regular bell, which was already in the case, and the second line through another capacitor to the other coil. To do this, the jumper between the coils must be disconnected. the call worked a little quieter, but quite well. It may be necessary to slightly adjust the gap between the coils and the bell drummer plate. Good luck))