ELSEMA gate opener crystal

[highflyer83]

Hello all,

I have a couple ELSEMA gate openers with a common problem, the legs on the through hole crystals keep cracking and breaking.  I'm trying to order a handful of spare crystals to have on hand for when this happens, but having trouble with this.  The crystals that are broken are labeled "6.786 KDV3Z" but I can't find anything online that has this same label.  Any thoughts as to where to get these?  Assuming I can get these crystals, my thought is to solder the new ones onto the FOB boards then apply a dab of hot glue or similar to try to have them last longer, that should be fine hey?

Thank you.

[fzabkar]

Could we see a photo?

[highflyer83]

For sure, try this one https://drive.google.com/open?id=1CIb1k7D-3IBmrgB4uL6sFHlchTADfDdx

You can make out the broken legs, one is easy to see, the other is just left of it going towards that IC with scraps of old glue/tape on it, that was holding the crystal.

[L_Euler]

Solder the new one in with a couple leg extensions so they can flex a bit.

[highflyer83]

The challenge is finding "the new one." How exact does a replacement need to be as far as its labeled frequency?  I can't find this exact number anywhere.

[fzabkar]

When I needed a special crystal decades ago, I had one custom cut by Hy-Q.

https://hy-q.com.au/crystals/index.htm
https://hy-q.com.au/pdf/Hy-Q%20Crystal%20Data.pdf

One other solution might be to replace the crystals in the transmitter and receiver with more commonly available matched pairs.

[fzabkar]

https://en.wikipedia.org/wiki/Citizens_band_radio

I suspect that the crystal frequency may be multiplied by 4 to give 27.144MHz.

A frequency of 27.145MHz is assigned to Radio Control Radio Service (RCRS) channel 15A.


Edit:

If you multiply by 64, the frequency becomes 434.304MHz.

434.300 MHz is channel 50 in the LPD433 band.

https://en.wikipedia.org/wiki/LPD433

"LPD is also used in vehicle key-less entry device, garage or gate openers and some outdoor home weather station products."

[L_Euler]

Looks like these guys have the right frequency:
http://ec91100103.sell.everychina.com/p-100239169-6-786mhz-hc-49s-quartz-crystal-resonator.html

[highflyer83]

That is what is happening.  There is a ICS501 set up to give 4x multiplier on the crystal.