Quartz Crystal Enclosure Types

[abem]

Hi.

I was cleaning and adjusting a 1977 Star Wars TI watch this evening when I noticed something a little unusual (perhaps). Instead of the usual cylindrical can shaped enclosure for the quartz crystal, this one has a transparent box shaped enclosure (made by Statek). I thought that these were only used for the very earliest quartz watches. I guess I was mistaken.

My understanding was that the transparent enclosures allowed the crystals to be tuned using laser trimming but were more expensive to produce. I have no idea how or if the crystals in the can enclosures were adjusted.

Anyhow, this was the first time that I have encountered one of these and I thought it was kinda neat. If anyone knows the details behind the various quartz crystal designs and trade offs, feel free to chime in.

-abe.

TI Module with transparent box shaped quartz crystal housing:

DSC_8140 (600x400).jpg

Close up of transparent box shaped quartz crystal housing:

DSC_8160 (600x400).jpg

[Kasper]

Hi Abe,

this one is from my old pontiac watch. It looks the same.

[bucko170]

I don't know much about those QC's other than Litronix used them and they are not very reliable often failing due to the seal being broken, I think they have been talked about on a previous thread and if I remember correctly the glass chamber is gas filled and once the seal is broken the gas escapes rendering the QC useless, also they cannot simply be exchanged for another QC of the same frequency......I will try to dig out the original information as it went into far more details.

Found it, vacuum sealed not gassed filled!

http://www.ledwatches.net/articles/Stat ... ystals.htm

[BENRUS]

I thought it was a little weird myself when I recently noticed the same with my newly acquired TI.
I've seen 3 different design assembly's in this same series with different battery contact plate/parts.

[LEDluvr]

Interesting observation Abe. I have a few T.I.'s, I'll check mine to see if they have the same q.c. out of curiosity.
It woudn't surprise me if Texas Intruments made this kind of crystal so decided to use their 'in house' version rather than pay for the usual "can" style q.c.