What is this circuit component?

[Polymer]

Looks like the OP is reverse engineering the cct ....

What does OP mean or stand for? Thanks!

[Skippy]

OP = Original Poster, that is the person who started this thread....... and then abandoned it?

[kt315]

Anyone know what is this component labeled 8838?

[ATTACH]36975[/ATTACH]

8838 is manufacture data. see 220.0 k - probably 220 pF and k is a voltage. http://bookz.ru/authors/andrei-ka6ka..._982/i_007.png
--- 63V

[Arthur-Canada]

It's on the circuit board of my 25 year old Wilson Relic and Coin ll metal detector. I think I may have damaged it with heat resoldering all the connection on the board.

[Skippy]

There's some other Wilson ccts on here, the 710 has a 220.0 crystal exactly like yours: Zip file:
http://www.geotech1.com/forums/attac...5&d=1212523464
Parts list: txt
http://www.geotech1.com/forums/attac...9&d=1212613891

Taken from this thread:
http://www.geotech1.com/forums/showt...ETECTOR-S-quot

Also: Coin Select pcb:
http://www.geotech1.com/forums/attac...9&d=1351758761

Regarding testing the part, you could probe around the nearby IC with a 'scope looking for 200 KHz / 100KHz etc divided down digital signals.
Or you could remove it from the PCB and make up a simple logic gate inverter based crystal oscillator, eg. 4000-series logic (CD4020 for example).

[Arthur-Canada]

Thanks Skippy but your suggest is way over my head! I sent it off to Keith Wills in hopes that he can fix it for me.

[kt315]

a face of skippy in a moment when he heard your answer

[Skippy]

My face showed 'disappointment', actually.

[Skippy]

Just for technical interest: The operating frequency of this machine (and several other similar Wilson-Neuman machines) is stated as 6.875 KHz. This is 220 KHz divided down by 32.
I also noticed their publicity states "Binary CMOS search-coil", which I guess is advertising baloney hinting at the digital 4000-series logic that drives the coil frequency.
The audio tone is also quoted as 215 Hz, which is 6.875 KHz divided down by 32. My guess is the 'unmarked' chip is a CD4020 oscillator/divider.

[dbanner]

The chip could be and is most likely the CD4060. The other thing could be a 220Khz glass encased crystal oscillator with internal cap to make it oscillate. Don't see any small pico caps nearby.

[Skippy]

I agree, CD4060 is more likely....and if I had paid attention to my 'Parts List.txt' link in my earlier post, it was listed as a 4060 on that.

[dbanner]

Did Wilson ever work for NASA? That component is atypical and of very high quality especially for its time. Not your garden variety for sure.

[Skippy]

At that frequency, the only main choices are ceramic resonators and tuning-fork crystals. I've used 100 kHz conventional crystals before, and they were huge (HC6U maybe ?) and expensive, not really suitable for detectors. It's probably lack of choice that led to that part.
The other obvious alternative is to use a higher freq crystal( >2MHz ) with more division.

I've just remembered another place I've seen that ceramic package. You used to be able to get a programmable oscillator/divider IC, in a regular DIL package, but with this ceramic boxed crystal visible in the top of it. You used pin selection to get the output frequency you wanted. There were two or three different master crystal freqs available. I can't find any mention of them on the web, and I've no idea if I have any 'spare' parts from the project I used them in, approx 1992.
Edit: Found it: Statek PXO series.
http://www.ebay.co.uk/itm/1PC-STATEK...-/121492945994

http://www.silicon-ark.co.uk/surplus...ator-by-statek

http://www.datasheet4u.com/datasheet....php?id=539290

Notice the date codes of these parts, 1984, 1987.

[dbanner]

Yes,I see. Why has no one used these in designing Tx oscillator to drive Tx coil and for phase shift. I've never seen these before in any metal detector schematic. By the way, I want to build the GC 1023 and have discovered that it is an exact clone of the fisher f2. Now all I need is a schematic since there good pics of the PCB on this forum.

[dbanner]

Turns out I was wrong about the f2. The search continues.