Memostar Alarm Crystal

[bobtheterrible]

Hi All,

My father has just given me his old Memostar Alarm watch he bought from the AA back in the 70s. It has seen some heavy use but overall it is in pretty reasonable condition. The immediate problems I can see are the missing crown and stem (hopefully I can source replacements for these) and a damaged crystal (cracked and chipped).

The crystal is an unusual shape and I don't know how to identify a replacement part. Does anyone here have any information (say a Sternkreuz part number) that could help me source another crystal?
 

Many thanks,

Bob

[watchweasol]

Hi Have a look on Cousins site , If I remember correctly there is some information to be had under the documents/PDFs regarding crystals and I think the sternkruze catalogue.

[bobtheterrible]

18 hours ago, watchweasol said:

Hi Have a look on Cousins site , If I remember correctly there is some information to be had under the documents/PDFs regarding crystals and I think the sternkruze catalogue.

Thanks for the suggestion watchweasol. I had a look through the Sternkreuz catalogue and couldn't see any obvious mention of this Memostar. They have an extensive range and there is a distinct possibility there is a crystal in there that would fit, I just dont know which one. /:)

[watchweasol]

Hi another site i Esslingers in the USA they have  tutorials on crystal fitting and sizing, always worth a loo also Jules Borel in the states have a good online site for information

 

[bobtheterrible]

I have not had much time to look into this. I had a quick peruse through the "Round Special Forms Plastic – Formproof" section of the Sternkruze catalogue. I think it suggests I need to get in touch with specific dimensions.... In the meanwhile, for those who come across this thread in the future here are some pics with dimensions:

 

[bobtheterrible]

Found one, or at least one that is close enough!

Im not sure that the profile is exact - the "corners" do not feel as pronounced and the old crystal has a tension ring whereas the one I found did not. However, it seems to fit well enough.

If anyone else is struggling for a replacement crystal this may work for them: GS CY945 29.7 22.8 31.5mm

[bobtheterrible]

Memostar goes "Brrrrrrrrrr"!

Finally got around to servicing my Memostar!

The movement was clean but pretty much all of the screws were in very tightly and sadlly some of the smaller screws started to deform before I noticed - my screwdrivers were a poor fit for these particular heads. 

The biggest challenge was getting the alarm marker lined up with the hands. I let down the main spring and positioned the hands to 12:00 using the date change-over as a reference. I then put some power into the bell spring and turned the alarm setting crown till the alarm went off. At this point I added all the hands and lo! The alarm trigger was off by 30mins - grr...

Also positioning the crystal is a real PITA. I put it all back together and the crystal is ever-so-slightly skewed despite my best efforts.