News:

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

Main Menu

Hungarian Mechanikai Müvek CB76MM

Started by LarryInMichigan, March 03, 2014, 01:03:15 PM

Previous topic - Next topic

LarryInMichigan

ebay link

I bought this phone a couple of weeks ago and just finished reassembling it a day or two ago.  Even though the date on the bottom is 1991, the phone looks like it's straight out of the 1970s.  The color is bright 'lipstick red', but the pictures make it look more orangeish.  The phone was pretty dirty and scratchy when it arrived.  It needed alot of cleaning, sanding, and polishing.  The handset cord needed recoiling.  I glued a rubber grommet to the bottom where the foot was missing, so the phone sits flat on the desk. 

The dial was made in Poland under license from FACE Standard.  The transmitter was made in East Germany (GDR) and completely dead (not unlike the GDR), so I used an Ericsson transmitter in its place.  The sound quality from the transmitter is poor, and there was alot of static, so I connect a 270Ω resistor in parallel.  That greatly reduced the static, but the sound is somewhat muffled.   I think that the styling is somewhat ugly, but the color is quite appealing.

Larry

Mr. Bones

Very nice phone , Larry!

Quite the eye-catching color; I like it.. 8)

Best regards!
Sláinte!
   Mr. Bones
      Rubricollis Ferus

Matilo Telephones

Lovely phone, Larry. I like these odd eastern European phones. They are different, aren't they?

How is it mechanically? Did you take pics of the inside?
Groeten,

Arwin

Check out my telephone website: http://www.matilo.eu/?lang=en

And I am on facebook too: www.facebook.com/matilosvintagetelephones

LarryInMichigan

I did not take any inside pictures.  My camera is not very good, and I have to change the batteries after every 20 pictures or so, so I try to be sparing with pictures.  The dial and hook switch are mounted to the inside of the shell.  The other parts are mounted on a PC board, and all of the wires have connectors which push onto posts on the board.

From a bit of web searching, I see that these phones came in a wide variety of colors, including yellow, green, white, ivory, gray, orange, and black.  I don't suppose that I will be able to collect all of the colors.

Larry

LarryInMichigan

I am guessing that the "CB76MM" which is molded into the ivory colored plastic piece on the front of the phone near the cradle is the model number where "CB" is for common battery, "76" is the year that the model was introduced, and "MM" stands for Mechanikai Müvek.  Am I correct?

Larry


Matilo Telephones

I suppose so, although CB by this time of production is a bit unnecary to distinguish the telephone, as by this time LB telephones have almost died out.

My Hungarian is almost non-existant so I cannot read what is written about this phone.

Sounds like the inside is typical for a nineties telephone. Thanks for the info.
Groeten,

Arwin

Check out my telephone website: http://www.matilo.eu/?lang=en

And I am on facebook too: www.facebook.com/matilosvintagetelephones

dsk

 :)
Very interesting.
Circuit comparison:
The ringer circuit, 1 uF capacitor in series with ringer.
The ringer are excluded from circuit in off-hook position, but the capacitor forms a part of a filter across the dial pulse contacts. (=Siemens 1928 to late 1970'ies)
Dial with only 3 wires, shorts the entire hybrid when dialing, probably loud click when dial rests. (=Siemens)
Hybrid = Siemens, but have a more complex line impedance circuit, not only a resistor. (picture ZB)
A unique signal level reduction circuit, with manual adjustment in several steps. (probably the same function solved at W.E. 500 a circuit with varistors, but this was automatic.) (enc.l pic. "damper")

dsk

LarryInMichigan

I hadn't noticed the various jumpers before.  There is a removable jumper connected between terminals 30 and 31, and jumper wires soldered between A - C and 10 - 21.  Would adding or removing any jumpers improve the sound quality?  It sounds like there is too much gain in the transmitter.

There is only a faint click when the dial stops.


Larry

dsk

Strap A-C are a part of the pulse contact filter. (has no effect on the voice path)
Strap 30-31 are a part of the line, I can not see why the option are there at all, removing this strap, and you are cutting out the voice circuit part of the telephone.

Strap 30-31 adds the C2 shunting the voice circuit. (probably negliable effect)
Strapping 32-33 will make the phone suitable for longer lines. (stronger signals in both directions) When even stronger signal are needed the removing of 30-31 strap may help a little.

dsk

LarryInMichigan

This morning I decided to give this phone another chance to work with my Ooma service.  Using a proven good German transmitter, the transmitted sound was very weak, so I moved the strap on the PC board from pins 30-31 to 32-33, and that made the transmitter sound noticeably louder.  Once I have had a couple of conversations with other people, I will know if it is loud enough.

Larry

dsk

Doesn't look like you may do much more to get it stronger, so if the transmitter works well on another phone on the same line, it should work well here too.  You may try a transmitter from a WE 2500 or equal to.

dsk

LarryInMichigan

I just tried the same transmitter in my Hungarian CB667, and it seems to work well there.

Larry

dsk

Then the transmitter should be good enough.

dsk