Help And Advice On Replacing A faulty Crystal

[keith777]

Hi guys.

i have looking at an old Viking VK20 Detector that needs some attention. first i had to replace the 16 flat ribbon cable that runs from the control box to the digital display box as someone had ripped the cable in half wear it goes in to the control box from the shaft. what a awkward way they have it fitting as well. anyways, i replaced that. so now i was getting digital display screen working with sound. on testing the coil against a metal object. no response. so i spent some time looking around the components on the board in the control box and the digital display box. i ended up noticing that the Crystal component on the control box board seemed to be a bit slack/loose. the main part of he it could pull up and down on it's pins. after a few pulls and pushes . i got the coil to pick up some comes etc. no great depth but at least i new the coil was working now.

so. can anyone please help me on replacing the Crystal. i have taken it off the board so i could take a photo of it. i tried to find a match for it's numbers on the internet but couldn't find anything. i am no expert in electronics. so can anyone please help finding a new one. or a compatible one to replace it with.

many thanks in advance.

[Carl-NC]

1.8432MHz
Digikey and other parts houses should have this.

[keith777]

1.8432MHz
Digikey and other parts houses should have this.

Hi Carl and thanks for replying to my post.
so as long as its a 1.8432MHz Crystal will it be fine? would this one be fine to use from off ebay. or does it need to have some other special series number or frequency tolerance size etc, etc. thanks in advance....

https://www.ebay.co.uk/itm/225089493...&segname=11051

[nickel_n]

only cost

Quantity	Price (ex VAT)
1+	?0.563

https://uk.farnell.com/abracon/ab-1-...7?st=1.8432mhz
but you may have to pay allot for postage

[Qiaozhi]

Hi Carl and thanks for replying to my post.
so as long as its a 1.8432MHz Crystal will it be fine? would this one be fine to use from off ebay. or does it need to have some other special series number or frequency tolerance size etc, etc. thanks in advance....

https://www.ebay.co.uk/itm/225089493...&segname=11051

Are you sure the crystal is the problem?
Since the VK20 has a digital display I assume it's powered by a micro. If the crystal was faulty than surely the display would not be working.

[Skippy]

It sounds to me that's it's the soldering to the crystal's pin(s) that was the problem. Simply re-soldering it would be the first thing to try.
If it's a modern crystal, it will have glass seals around where the lead enters the body. If they are destroyed enough for the body to move, then there is not going to be a vacuum inside, and no way will the crystal ever resonate again.

[sinclairuser]

please dont take this the wrong way, but that viking detector would be great for building a project with, switch out the board and coil with your own and you have a good machine.
repairing the vk20? not so much, the viking machines were, are,, and will always be crap.
i cant understand why they still sell this rubbish in 2022.
please dont flame just personal experience and opinion.

[keith777]

Are you sure the crystal is the problem?
Since the VK20 has a digital display I assume it's powered by a micro. If the crystal was faulty than surely the display would not be working.

i soldered the crystal back in to the board. now i can't get any response from the coil. i think the two legs have been moved in and out of the crystal to much. i have bought that crystal i showed in the ebay link. it was only ?2.88 free postage. so very little to give it a try and see if it works. the Link that Carl gave me. the part is only ?0.73 but the postage will cost. (A delivery charge of ?33 will be billed on orders less than ?33) madness.

[Carl-NC]

Since you've ordered the proper crystal this is just FYI but usually you can stick in something close (say, 2MHz) and it will still work, but maybe the audio pitch will be higher.

[keith777]

Since you've ordered the proper crystal this is just FYI but usually you can stick in something close (say, 2MHz) and it will still work, but maybe the audio pitch will be higher.

Carl thanks for that bit of info...........

[sinclairuser]

i soldered the crystal back in to the board. now i can't get any response from the coil. i think the two legs have been moved in and out of the crystal to much. i have bought that crystal i showed in the ebay link. it was only ?2.88 free postage. so very little to give it a try and see if it works. the Link that Carl gave me. the part is only ?0.73 but the postage will cost. (A delivery charge of ?33 will be billed on orders less than ?33) madness.

usually the ? is in reference to a pound sign or some other unit of currency, in this case mabye a pound sign.

[keith777]

usually the ? is in reference to a pound sign or some other unit of currency, in this case mabye a pound sign.

i used the pound sign but the forum changed them all to a ? it has done this in the past to me as well. here is some off the key board to see if it changes them again. ?????????????? i can see all the pound signs ok on the reply section as i am looking now. lets see what happens as i click on the post reply button.

[keith777]

yes it has done it again. there must be a bug in the forum software some wear.

[Skippy]

I've always typed Pounds GB on here, because of this. I also type US Dollar; even though that's probably the only currency symbol it will recognise correctly.

For a test:

??? Pounds

$$$ Dollar

Edit: After submission, I see question-marks for Pounds, dollar symbols for Dollars.

[sinclairuser]

its because the forum is expecting a us keyboard, some us keyboards dont have pound sign, others are where our ? symbols are next to the shift key on the right hand side.
thats why typing a pound symbol on a uk keyboard on an american site produces a ?
in therory typing ?????? should produce pound signs at the other end.
but it doesn't it types ?????? weird or what.