minelab xt1700

[Chiv]

I'm getting way way out of my leuge on this machine. It has a problem starting up. It only running with lots of speaker noise and with the scope shows it running at 930hz in stead of 32khz. now I'm thinking a capacitor/s has died in the tank circuit. This little fella (0.01uf 63v polyester film box capacitor BF014D0103kdd) get very hot. before it would some times fire up and run sweet as, other time runs but unstable lots of chatter, but now it has a sad face all the time
Most of the numbers have been wiped of critical components.
If a capacitor getting hot could that be from working to hard or shorting out internally? just trying to get a feel of where in the circuit I should be looking.
will get some pic of the board when I get a chance so you all can see what I'm looking at

[Chiv]

couple quick snaps
[

[waltr]

a 10nF cap should not be getting hot. It does sound like it has gone bad.

[kt315]

nice pics Chiv.

can you send me more, both pcb side, also from pots side, in high definition?
my email [email protected]

TIA

[Chiv]

not a problem kt315 will get better pics later on as need to get the light right as its been painted with some type of clear lacquer that makes the lot very glossy, got to get the light just right. have been taking a few macro shot of the chips that have been wiped with what ever to get rid of the id marks and with the right settings I can bring the numbers out enough to get id on them,
thanks Waltr I was thinking that was the problem one been hot as, burns when touching it, first pic is of the tank circuit all in that corner going to draw it out on paper to try and make sense of it all, as there is a switch in the tank circuit for switching between 32khz to 6.5khz which still works when have it on the scope so narrowing it down slowly back to that one cap

[Melbeta]

Chiv
Very nice photos Chiv. When you send them to KT315, send some copies to me as well, at Pondco at Aol dot Com. I would appreciate the photos as well.
Melbeta

[homefire]

If a Cap is getting hot it shorted.

[Koala]

Quite likely to be a faulty capacitor

Could be high amps running through it.

[Davor]

It is a tank capacitor, so hundreds of mA are running through it.

[Melbeta]

not a problem kt315 will get better pics later on as need to get the light right as its been painted with some type of clear lacquer that makes the lot very glossy, got to get the light just right. have been taking a few macro shot of the chips that have been wiped with what ever to get rid of the id marks and with the right settings I can bring the numbers out enough to get id on them,
thanks Waltr I was thinking that was the problem one been hot as, burns when touching it, first pic is of the tank circuit all in that corner going to draw it out on paper to try and make sense of it all, as there is a switch in the tank circuit for switching between 32khz to 6.5khz which still works when have it on the scope so narrowing it down slowly back to that one cap

Chiv
Thanks for the photos. I am not interested in making a PCB for the XT17000 detector. If I made any schematics, it would be to fix a defective unit for my own use. KT-315 can make the boards. I am not in that business. I use vintage metal detectors, not interested in newer programmable units...

I am into going into Colorado gold placer areas, and was interested in trying to find a reasonably priced Minelab XT17000 detector. And if necessary, would try to repair one if it was reasonable enough. I hunt for gold nuggets in placer areas, and also find meteorites along with hot rocks. And I know the difference between them as I studied Geology. And I wrote Gold Placer books in the past.

And I use the Compass Yukon 76b, which is the body mount version of the 77b that you use. The part you speak of that is black in color, use tuner solution and give it time to dissolve any material inside as it should loosen up. Do not force it. It tunes between mineral side, through the null region, into metal side. It is a 10K center tune pot. If that tuner solution does not free it, then I would try WD40 as a second solution.

Again, thanks for the photos. I appreciate them very much.
Melbeta

[Chiv]

Not a problem at all Melbeta, yep got the 77b working really nice, if I keep out of the real wet mineralized beach sand it also not bad but not as good as the barra, still trying to sort out the xt17000 but doing my head in but getting there slowly