SMT Bandito Info/Build

[Davor]

I have Rev.1, but I have no idea how good this PCB is

[seadoggy]

Any one have bandito layout not SMT parts??
Regards

[Koala]

Been out with the new coil. Long wet grass was no problem. Like it. Ran with zero discrimination. Did not dig much iron. Some of that was just to make sure. Going to take a bit to get use to the tones.

Hard to explain but seems to hit a target much stronger than my IDX as you sweep you know instantly if it good and just go back over it to pinpoint it. IDX I was continually going back and checking pop and beeps.

Fields weren't that productive but did as well as everyone else



~

One nice feature which I never noticed with the IDX is in all metal mode iron gives a longer beep

[Koala]

Yep after all that just the coil. With the 5.7" concentric. Big coins top out at 9" so not bad when compared to my IDX with a 10" DD coil which tops out at 13.5"

Tiny silver coin the would fit on your little finger nail is 6" in fact most small targets are around 7".

Discrimination seems fine foil cuts out nicely. I was slightly disappointed when compared with some video on YouTube but could not find a video with the 5.75 and Bandidio.

[Koala]

Not 100% on this but looking like its the coil. Built another using the same specifications and its not turned out as deep. However there does not appear to be any drop off at 0 discrimination. Could be the poor performance masking any drop off but as the distance is linear as a turn the potentiometer up and down it looks hopeful.

[Koala]

check (by MEASURING) R48 R50 and poliarity of VD7. also, set yet one diod to VD7 in serial (1N414.

R48 and R50 measure okay

VD7 measured okay with a diode test and is the correct way round.

Sent some time inspecting the board for shorts looks okay to me.

Strange how it fail on both the first and last few degrees of the potentiometer. Tried a different potentiometer and it was the same.

So close to working its usable as long as you remember the first part of the potentiometer looses 50% depth.

[kt315]

check (by MEASURING) R48 R50 and poliarity of VD7. also, set yet one diod to VD7 in serial (1N414.

[Koala]

I have a problem for sure but can't pin it down.

When in discrimination mode if I set the dice to 0 then the depth will be poor. If I slowly turn the disc up there is a crack from the speaker an the detection depth will be correct and the discrimination also seems to work fine.

Also at the other end discrimination full there is a sharp cut off.

First and last 1/4 is useless but the middle 1/2 is working fine.


Also discrimination affects threshold tone ?? when set to 0 the tone wobbles up and down but if I turn it up then it settles down.


Ground balance is in the middle of its adjustment so hopping the coil I made is okay.



Not 100 % on the switches. Connected as per Carl's schematics but have seen different connections posted.

[Koala]

Well generally impressed with this detector.


Made a 5.75" concentric coil (now being glued)


All metal and discrimination both working well (some of the time)


Getting up to 8" on a Canadian dim or UK silver six pence


However having a few problems with the switches /reliability


Auto / Manual both work in All Metal Mode. In auto the tone decreases if I hold a target still but in manual the tone stays loud as expected. But in auto I can get a nice threshold tone but in manual I never get a threshold tone but lowering the threshold does lower the distance.


In discrimination mode the distance I get alters when I switch it on it could be anywhere from 4" to 8". One time the distance came back just by lowering the threshold down and back up. Other times it requires a few goes with the retune


Would not be good to be out on a field only detecting at 50%. There would be no way of knowing.

[Koala]

Well. Not sure whats going on.

If I switch the soldering iron off and rest the tip against the battery negative terminal the detector works fine in all modes. Works even if I pull the mains cord out of the back of the iron.


At least I don't have to start to check for miss placed components as most of the SMD are unmarked



Still looking for the original specs for a Tesoro 5.75" concentric coil.

[Koala]

Too many projects on the go an this got shelved.


Had a need a detector with a small coil for some trash area I want to detect. As this has a true no motion all metal mode I have decided to finish it of.


All gone together well turns on. Discrimination,threshold and All metal mode work in auto mode. In manual mode the detector all I get is a high threshold tone and moving near any of the potentiometers makes is alter. Earthed the potentiometer cases made no difference.

Whole thing might need to be in a metal case to calm it down??


Done a quick Google. Can't find the original specs for the 5.75" concentric coil

[Silver Dollar]

I built up the original oscillator for the 440 today and it works good!
At 10 khz it puts out a 17.8v P/P signal and uses 4.5ma. The only
problem is it uses the -V so the center tapped TX can be grounded
so I have to find 4.5ma's to feed it.

I also found some MAX667 LOD's today, they can be adjusted so you
can run the Bandito on 6V to gain a bit of depth. I know I lost depth
going from 8 to 5v on the TGSL (so I'll use one there too to get 7v).

Actually I might be able to go to 7v on bandito too as I replaced the
2262's with some chopper amps that can use more voltage....

[Silver Dollar]

Well I set mine up to use the tracker coil. It's light and shielded and works great!
My attempts at coil making have not gone well. I tried a TGSL coil with CT RX and
no shields but it is a bit noisy. I used epoxy to fill it and its a bit heavy too!

The other coil I attempted was a minelab style with screen shielding and I couldn't
get it to work stable. I have it hot melt glued but it can move enough to mess up the
the null so I'm still not happy with it. So I went back to purchasing factory coils for now.

My latest is a Fisher 440 11" coil. It has a CT TX of 12.6mh and RX of 12.6mh. I'm working
on a TX oscillator for it now...

[Koala]

At last the final parts from Mouser have shown up today. Was getting a bit worried.

Still trying to make decent lightweight coils. Windings are easy having problems getting the stable shield that's immune to knocks and touching the ground. It's no good having 40 cm on the bench but the coil is unusable in the field.

[Koala]

Thanks for taking the time to photo the inside. I am interested in all Tesoro original coils as there seem to be a lack of data on the internet. Which are center tapped build configuration Et cetera all add to my knowledge.