Zenith 28800 Sporto

[vultures78]

Hi everyone

Here is my newest Zenith is Zenith 28800 Sporto with goldfilled case and stainless steel back. Inside ticks a Zenith 2562 movement and watch is by my standards very precise. Here are some pictures of the watch. There is no serial number on the movement so my question is can watch be dated by case number only? Any other comments and suggestions are more than welcome

[Hartmut Richter]

Nice little number. You should be able to date it from the serial number of the case (presumably something like 000X000 where 0 are numbers and X is a letter, probably D) but not to the exact day. The new Zenith book gives a similar watch with steel case and blue dial and without the 28800 on the dial from 1969 with a ca. 2552 PC. This would be a little earlier than the 2562. Those examples from the mid-seventies with 28800 on the dial in the book have a more rectangular case. I would therefore guess that yours is from ca. 1971-72.

Hartmut Richter

[vultures78]

Hi Hartmut,

Thank you for your promt reply. Case has serial number 20 1291 125, so there are no letters in serial number.

[Hartmut Richter]

Hi Hartmut,

Thank you for your promt reply. Case has serial number 20 1291 125, so there are no letters in serial number.

Hmmmm. Sounds a little more like the reference number of the watch type than the serial number of the watch. I will do some research....

Hartmut Richter

[vultures78]

Here is a picture of outter side of the case, so it is more clear.
Should you need any additional info please feel free to aks and thank you very much in advance.

[Hartmut Richter]

The new Zenith book states that from about 1970, a new reference number system was established. The first two digits denoted the case material (20 in this case meaning 20µm gold plate), the second set the model number and the third set the calibre. 125 was presumably the code for the Cal. 2562. Later, the movements got three digit numbers which could be used directly, e.g. 400 for the basic El Primero. The case number should be etched rather more thinly onto the back of the case and may have worn off by now. It should have a letter in the middle.

[D N Ravenna]

Any way you cut it, that is a nice looking watch! Congrats on the good find and wear it in good health!



Dan

[vultures78]

Hartmut thank you for all information about my watch and on decoding the case serial number. What book are you refering to and where can one buy it? Thank you very much Dan.

What does your book says about this Zenith 2552C.
I am posting two pictures of case (inside and outside) because there is no serial number on movement. This case has D in the middle.

inner side



outter side

[Hartmut Richter]

The book I refer to is the newly brought out "Zenith - Präzisionsuhren seit 1865" (Zenith - precision watches since 1865) by Manfred Rössler, publ.: Ebner Verlag, Ulm (Germany). Only available in German, I'm afraid. See my earlier thread:

Quick review of M. Rössler's new book on Zenith

As for the Cal. 2552 watch, the book is a little scant as far as details of serial numbers go. Generally, the letter-in-the-middle serial numbers were supposed to have come out around 1963. They started with an A, then used a D and later an E. Two watches with Ds in the book are dated 1968. I also believe that movement serial numbers "expired" in the later half of the sixties. Since you have what is probably the calibre code (1201) on the inside and this is not part of the 00.0000.000 system, I would tentatively say 1968-1970. Zenith may be able to give you a close idea but you will never get an exact date such as from a movement SN.

Hartmut Richter