Bandido 2 Modified

[chemelec]

Looking at the pictures of the PCBs on Gary's website, it looks like the emitter of the pass transistor is turned towards pin5 of the 7660 ic.
Something must be wrong somewhere in that area. The schematic shows the collector connected to pin5.

Merc


http://www3.telus.net/chemelec/Proje...it/2-SIDES.JPG

It Is CORRECT on the Circuit Board. Sorry, It is a 2N3904, NPN Transistor and Backwards on the Schematic.

And YES IT WORK. Also Tested Outside.

However I don't find the Descrimination very good.

Would be great if Someone could Varify Cap Values.
I have Recieved Numerous Opinions on these!

[Merc]

I tested the detector with the coil on my wooden table. I was careful to avoid any metal on the underside of the table. I also picked it and held it in my hand (without jewelry of course). The problem was that the caps were totally wrong. Gary's schematic "works" on the bench but is not viable in the field. That's just my opinion. The capacitor values given in the phase shifting circuit are way off.

Merc

[TryAgain]

Hello Merc
Just read thru your build ,nice job looks nice.
I was wondering when you were having trouble with ground balance not having enough phase adjustment , did you have the coil mounted on the "S" rod?
Reason I ask is that looks like its an older style with an aluminum down shaft a few inch's away from coil , and its in the field of the coil and upsetting the phase angle, so maybe that's why you could not balance out the ferrite with the given component values on the schematic.
Just a thought

[Merc]

In looking back at this detector, I remember I had to bypass the pass transistor for the negative supply. The negative supply would not work as shown on Chemelec's schematic. A 1K resistor is needed from the collector to the base of the PNP passing transistor as is shown on the original Bandido II schematic posted by Carl. Just a note for anyone who might build.

Merc

P.S. Still can't get battery test to work properly...

[driscoll]

Sorry Merc, but the original µMax Bandido II use surface mount components. It is not easy to examine and test.

Bests regards.

[Merc]

driscoll,
Could you examine the circuit in your detector and compare it to the schematic on this forum and point out any differences?

Merc

[driscoll]

"I'm still not happy with the battery check. I can't see any way for it to work properly the way it's designed on the schematic. I was hoping someone on this forum might have an original Bandido II uMax that they could check. I'd like to know if the length of the test signal varies with battery strength as the manual suggests."

Hi Merc,

Yes, i have an original µMax Bandido II and the length of the test signal varies with battery strength.

These informations are in the manual.

Regards

[Merc]

It is working. It's nothing out of the ordinary. I still don't believe the battery test is working as it should, but I quit worrying about it. I've moved on to my second detector building project, a lightweight version of the Toltec 100.

Merc

[silverdog]

Hi Merc

What a great job you have done on your Bandido II - did you finally get everything working ok ?
Would love to see some more pics if possible, I fancy having a go at a Tesoro soon, you have inspired me !!

please update us

[Merc]

Woody:
I still have not figured out this battery check, but before I build another one, I will.

Ivconic:
You have inspired me try and build my own double D coil. I will probably follow your recommendations in your TGSL instructions. I am going to cheat a little by buying an enclosure from here: http://www.hayselectronics.com/parts.htm . I have ordered the housing designated "A". The price was only $14 USD. Once I have it, I'll trace the shape out on a piece of wood and use the dowel pins as you did. Simple I hope. Number of windings could vary a little since the diameter is probably not identical to what you made.

Merc

[woody]

forgot to add got it from this site
http://www.volny.cz/kachlik.jan/

[woody]

found it here
http://www.volny.cz/kachlik.jan/dete...ido_II_sch.pdf

[Merc]

I'm still not happy with the battery check. I can't see any way for it to work properly the way it's designed on the schematic. I was hoping someone on this forum might have an original Bandido II uMax that they could check. I'd like to know if the length of the test signal varies with battery strength as the manual suggests.



Woody, which schematic are you looking at that shows the different resistor values?

Merc

[woody]

did you get the battary check working there are so many schematics for the bandido who knows which is working or not
have you tried
adding R24 68k
change R11 200k for 2M
swap R8-R9
put a jumper on j1
put a biocolor led on j2

[ivconic]

Your work is clean so i think bulky wires would not cause any extra problem. I opened Bandido II, Eldorado and Silver Sabre, so far, and i saw pretty bulky wirements in those originals too. However...those were in metalic enclosures...except Bandido II which has "I___I" shape metalic holder that can act as good shielding also.
Speaking of sensitivity..; with coil on your photo you can not achieve some extra results. I had same coil with my Bandido II. Poor performances too. But once i connected my DD handmade on original Bandido II...! Wow! Extra good performances! That was the same handmade DD coil explained in "Tesoro Golden Sabre" thread.
So...you have good machine for sure and now is time to make good coil. I suggest you to do that and than i am sure you will be very satisfied with your detector. Try and see.
Regards!