Huhges module crystal frequency

[egomon]

I have about 7 different (color) hughes modules and 3 of them have sticker on top of the crystal. I think it is the crystal frecuency!?

Some modules work some do not work.

There is no sticker on top of 4 crystals. Is there eny possibilety to finde out what frequency crystal do I need on these modules?
Is there eny crystel available enymore for hughes modules?


Thank you

[bucko170]

Hughes QC frequency is 786,432Hz, the sticker on the crystal is probably the date (month and year, 6-76) these QC's are not produced any more but spares salvaged from old defunct modules can still be found.

[egomon]

Thank you. I think i have 2 broken modules with working crystal what i can use.
Will trye to do some crystal swaping.

[azimuth_pl]

you have to be careful when removing the quartz which is usually secured with tough epoxy on the 29mm modules. don't use to much force as you might break the substrate.
the middle third leg of the quartz might be missing on some versions but it's not that necessary to function as it's just ground.

here you have a huge Hughes quartz compared to a modern 32768Hz tuning-fork shaped crystal.
a long 32768Hz 1970's vintage Motorola crystal is visible in the background.