Minelab GT16000 tips, settings, questions

Hi everyone
I am after a copy of the minelab wiring diagram or circuit board schematics for the GT16000 or FT16000 as I have a GT that has a burn't capacitor on the board and I'm not really sure what sort it is. I have attached a couple of photo to refer to. It is marked C36 on the board and sit next to two other similar capacitors. Any help would be greatly appreciated.
Thanks
Firey10_0

I believe that's a tantalum capacitor:
http://www.learningaboutelectronics.com/Articles/How-to-read-a-tantalum-capacitor.php

Hi grubstake
Thanks for the reply. Had a look at your link but this capacitor is a black one with 3 legs like the other 2 near it. Not sure if the tantalum capacitor your referring to can also look like this. The other thing is I need to know what value capacitor this is to replace it.
Again any help would be greatly appreciated.
Thanks
Firey10_0

Black with three legs is a transistor, not a capacitor, mate. Very different animal.
If there's no writing on it to identify it, you may be out of luck unless a circuit diagram is available.

FYI, I have highlighted visible transistors in your pic below (at least I think the group in the foreground are transistors - the pic is so out of focus that it's hard to be sure. The other one highlighted beside the two large, upright, blue, electrolytic capacitors, is definitely a transistor):

TAG's can do that... Look around and see what others are on the board...

Capacitance Value is not that Critical for TAGs in general, but VOLTAGE ratings ARE... Same or Higher Voltage, never lower...

But I would be checking the voltages, as it could be a sign of something more involved..

Hi again
I had a closer look and I was incorrect. It does have 2 legs and looks black in colour. Not sure if that's because it's burn't but there's only blue ones on the rest of the board similar to the blue ones in front of the burn't one in these new photos. Hopefully there a bit clearer. Let me know what you guys think.
Thanks
Firey10_0

Here's a better pic of the blue one in front

The three vertical dark blue/silver components are tantalum capacitors. The cooked component appears to be a small electrolytic capacitor (polarity markings are visible on the PC board), but the value markings look to have been burnt off it. If you have a close look around the circuitry, you might find a similar but undamaged electrolytic capacitor with intact value markings that could provide a guide to a replacement for the cremated one.

FYI, electrolytic capacitors typically fail eventually when the electrolyte inside them dries out, so if this one has gone, others might soon follow. :/

Hi grubstake
Thanks for the update. I had a look at some images of electrolytic capacitors as I wasn't sure what they looked like. All the ones on Google seemed to be round in shape but this one I don't think is. I've attached another side shot of it so you can see it at a different angle and let me know if u still think it is one. I also had a look on the rest of the 2 boards and I can't find one anywhere that looks similar other then the blue ones which appear to be similar shape but different colour. Hope you can help thanks
firey10_0

I am going to say it is a TAG .

The blue are for sure, but the pic quality is crappy. From what i can see the black one has the same bottom shape and same pins.... but that is all i can see...

Cut it out and have a close look...

If it is short, then removing it may also allow the machine to start.

TAGs and Electros do not usually cause a board to fail unless they are short... if open cct or removed, then filtering and or other minor effects may be seen. But in many cases you may not see any problem, unless under load......

If a few have failed, then that is a different situation.

Hi angermanagement
Pardon my ignorance but what is a TAG. Thanks
Firey10_0

Type of capacitor referring to it's construction.
I have a GT1600 detector in working condition.
I can pull it apart and identify your components if needed.

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

I would say at the least there would be more caps gone in it.
I am surprised that this much damage has been caused.
Imho, There must have been a catastrophic failure some where
to cause this extent.
A lot of the IC's have had their values removed to protect the
company's intrest's.
And they also started to paint the boards white as well.

Hi tathradj
This is the only damage I can see on any of the components on either circuit board. If you could pull yours apart and get a pick of this part and the components value numbers that would be great. I'm hoping once I replace this It'll work again as before this happened it was working fine. Hope you can help.
Thanks
Firey10_0

Yep its a cap. I did look through my circuits but I don't have that model. By looking at where it is in the circuit, you can generally figure out what value it is (or close to it anyway).

For it to burn up like that, it will be one of 2 scenarios. Either the cap has gone short (tantalums are notorious for that) or something driving the voltages on that rail (a fet or bipolar transistor) has failed causing a higher voltage to feed to that cap, which in turn caused it to burn up.

You'll really need to look at the circuitry and draw a bit of a circuit of the local area just to see whats going on. Just replacing the cap without establishing the underlying cause may (and usually will) cause further damage to circuitry further down the line.

I have a detector in for repair at the moment that would have been a simple FET replacement but someone else had a look and when reassembling it, they pinched one of the cables causing it to short. It now has multiple areas of damage and, unfortunately, may not be worth repairing.

May or may not be related but I see possibly a
flyback transformer in the same local.
Give me a few days and I will have a look at mine.
Very true about shot gun repairs.

Hi steelphase
I had a good look over the circuit boards and couldn't see any other damaged areas. If something was damaged would it be visible with some sort of burn mark.??
I don't know of anyone here in sa that would look at an old detector like this. I was hoping with just that being the issue I can easily replace it and hopefully she'll fire up.
Thanks tethradj for your time in pulling yours a part.hopefully you can find the right parts.
Thanks
Firey10_0

Failed components don't often have obvious signs of failure. A leaky or shorted fet/transistor will physically look ok. Only way to tell is using a meter. But I would start by drawing a mudmap of where the burnt components is in circuit and you can then generally work out what else may be faulty. Sorry I cant be of more help. If you were closer to Geelong I'd have a look for you.

Unfortunately I don't know of any repair shops in SA. Perhaps give Nenad at Phase Technical a call. He may know of someone. Finding people to repair electronics these days is getting more and more difficult. Circuit fault finding is a bit of a dying art. Most of us in the trade with fault finding experience are getting older, getting closer to retirement or are closing doors as people just don't want to spend money repairing things. Customers are more demanding and it doesn't make the service industry an enjoyable occupation. Myself, I'll be closing the workshop next year and working purely on the steelPHASE stuff from home. Less overheads, doing something I love and none of the abusive customers.

from memory the gt and ft are different boards in the early days we had fts that had a variable tone control added, we copied it on to a gt but it did not work as the boards were different we finally figured it out regards john

Hello All.

I'm wondering if anyone has any info on what Coils are still out there to suit my old GT16000.
Minelab produced them in late 80's.......1989 I think.
I know that the "Musketeer" and "Eldorado" and of course the FT16000 coils would fit...but unsure of anything else.

Thanks.