error wile wuilding the bandido

[Stijn]

hi,

im building a bandido and i finished the whole print.
i get 5.04V on the V+ points (wicht is wat i need i gues) and my battery gives me around 9V.
but my batterie check gives me a red LED.
aafter some time i found that my print doesent give me a +5V at the -V point but 0.00V.
does someone know wat can be the problem of this ???

best regards,
stijn

[Qiaozhi]

hi,

im building a bandido and i finished the whole print.
i get 5.04V on the V+ points (wicht is wat i need i gues) and my battery gives me around 9V.
but my batterie check gives me a red LED.
aafter some time i found that my print doesent give me a +5V at the -V point but 0.00V.
does someone know wat can be the problem of this ???

best regards,
stijn

Hi stijn,

You will need to provide more information than this, if you want anyone to help diagnose the problem.
Have you checked whether the TX circuit is oscillating? If so, then how about the divider circuit which drives the charge pump? The problem could be anywhere in this chain.

[Max]

hi,

im building a bandido and i finished the whole print.
i get 5.04V on the V+ points (wicht is wat i need i gues) and my battery gives me around 9V.
but my batterie check gives me a red LED.
aafter some time i found that my print doesent give me a +5V at the -V point but 0.00V.
does someone know wat can be the problem of this ???

best regards,
stijn

Hi,
on +V you get +5V and on -V you will get something from -3.0 to -4.0V ...with an average value that I think could be -3.2...-3.3V at right conditions (components, osc working, right schematic/pcb...right speaker...etc).
Anyway you can't get -5V on -V rail in any case with original voltage converter...but you can modifing it with e.g. an ic 7660 and some other components...but it's not required...you only need some -3 volt to get it works and also good !
If you coil is wrong or for any other reason you haven't oscillations you can't get any negative voltage cause clock signal is absent and converter doesn't work (it works at 5KHz due to clock/2 by 4024 counter).

Best regards,
Max

[Stijn]

k i found out that my oscillator doesent start (gues thats the problem why i dont get -5V)
the question is doe i connect the number 1 or the number 5 too the ground cuase i now have the 5 connected too the ground (the numbers are the numbers on the connector 2 is not used, 3 and 4 are for the Rx coil, 1 and 5 are for the Tx and the 5 and 3 are connected inside)

best regards,
stijn

[Max]

k i found out that my oscillator doesent start (gues thats the problem why i dont get -5V)
the question is doe i connect the number 1 or the number 5 too the ground cuase i now have the 5 connected too the ground (the numbers are the numbers on the connector 2 is not used, 3 and 4 are for the Rx coil, 1 and 5 are for the Tx and the 5 and 3 are connected inside)

best regards,
stijn

Hi,
actually is viceversa...mean that oscillator working with +5v only and then to have negative -V rail you need it as clock for 4024...then it's frequency/2 drive the voltage converter...
So if you haven't oscillations you can't get any negative voltage (must be something -2.8v to -3.3v...not -5v in any case).
You just need connecting tx coil to get oscillations from colpitts osc.
Then you could figure out how to connect rx coil.
If your coil is original you have internal connection between them and don't need to replicate this connection at pcb leads...this way you get a gnd loop and that's not a good idea.

Just find the error on your oscillator...I mean check everything including (which kind of transistor have you used ???) direction and pins of osc transistor. Keep in mind that 2N390x have reversed collector-emitter respect to the e.g. european bc547 or similar bf transistors in same case.
If you have used europeans ones you need keep them turned 180° respect to original ones position. Otherwise you can't get oscillations.
Another issue is gain of osc transistor...find one with at least hfe=100 to be sure it oscillate easy !
Also check capacitors values...resistors in osc section and also measure coil resistance/inductance if you can ...need to read something 20-22 ohm with about 5.8-6mH inductance.

Best regards,
Max

[Qiaozhi]

k i found out that my oscillator doesent start (gues thats the problem why i dont get -5V)
the question is doe i connect the number 1 or the number 5 too the ground cuase i now have the 5 connected too the ground (the numbers are the numbers on the connector 2 is not used, 3 and 4 are for the Rx coil, 1 and 5 are for the Tx and the 5 and 3 are connected inside)

best regards,
stijn

The coil wiring is correct. Maybe you have the transistor connected back-to-front as Max suggested.

[Stijn]

k i changed the transistors and got my oscillator zorking but now my detector just screams for 3 seconds and the he just screams some more but not so hard.
cant figure out were the problem is im gone change the rest of my transistors too and see if that solves the problem but if some on knows the problem and its not the transistors pls let me know

best regards
stijn

[ApBerg]

Hello Stijn.

The 3 second are the batt.check, what schematic are you using ?
Als je Nederland spreek kan je me ook een PMail sturen, dit kan via het forum.

Best regards

Ap

[Max]

k i changed the transistors and got my oscillator zorking but now my detector just screams for 3 seconds and the he just screams some more but not so hard.
cant figure out were the problem is im gone change the rest of my transistors too and see if that solves the problem but if some on knows the problem and its not the transistors pls let me know

best regards
stijn

Hi,
as i said before:
Keep in mind that 2N390x have reversed collector-emitter respect to the e.g. european bc547 or similar bf transistors in same case.
Use all the same pnp or npn to avoid such kind of problems e.g. pairs like 2n3906-2n3904 or e.g. bc547-bc557 and the like. Remember that pins of collector and emitter are to be reversed ...so round 180° them all if you switch from 2n390x to some bc5x7.
It's normal to have 3-4 seconds scream every time you power it up...it's battery checker as signaled in previous post. You have to start it in disc mode (to ear the batt check tone disappearing after the 3-4 seconds) then switch to all-metal (auto) and try to get some threshold moving the threshold pot...if you ear a steady hum and can control its strenght you are on the right way... and your bandido works like expected.

Be really careful with preamp and middle stage ...keep osc readings at sampling gates control pins and check them with goodrat's diagrams you can find in older posts about bandido. If you see same variations it will be fine.
I refer to gnd pot and disc pot to check diagrams...also put the probes as I've indicated in that post...cause goodrat's indications refer to an original cutlass and not bandido.

If it works this way...you could get 1 eur coin at more than 30cm in air tests... or also far away. Much depends on your coil too.

Best regards,
Max

[Stijn]

hi

i have got 2 questions

i have connected the 2 disc points with a piece of wire and i havent put a switch (i dont have retune or all-metal)
could this be the reason my detector doesent work ??

second question is that i got a TL062 instead of an TLC2262
is this a good replacement comonent ??

best regards,
stijn

[Max]

hi

i have got 2 questions

i have connected the 2 disc points with a piece of wire and i havent put a switch (i dont have retune or all-metal)
could this be the reason my detector doesent work ??

second question is that i got a TL062 instead of an TLC2262
is this a good replacement comonent ??

best regards,
stijn

Hi,
1. do you mean on workbench or outside (field test) ?
If it haven't returne or all-metal you can't get it ground balanced on the field...cause you can't hear the hum sound increase or decrease...and also you can't switch in manual (all) and then use retune to do the same thing.
On workbench it's not a problem having just disc mode...if you want. It must work in disc mode on workbench also without any ground-balance (you coil is in air and far away metal objects , right ?).

2. well...no it isn't. TL062 draw more current...but it's not the problem here...problem is that is noisy (compared to tlc2262) and that it's not rail-to-rail...then tend to saturate quite easy...and that's not good in Bandido.
So...avoid TL062 and , if you can't get TLC2262, get something like these:
- ts27m2cp (stmicro)
- ls204 (stmicro)
They have same consumption and about same noise figure...though they aren't tlc2262 (or TLC2252, or TLV2262 etc that are fully compatible with 2262). You can use them with success on bandido.

Best regards,
Max

[Stijn]

hi max,

for some strange reason i got a mail today to tell me about the replay u gave me 2 years ago and i didn't see it here before, really strange .
anyway, i made the badido for a project in school almost 2 years ago and was not really good at electronics back then so i could not really figure out why it refused to work.
btw the guy in the shop where i got my components ensured me the TL062 was a decent replacement and wasen't gone mess with the desing
butt still the only way i could get a bleep was when i turned everyting to max and put a big piece of metal right in front of it.

after getting some help from a teacher we found out that the TL062 was in fact the problem maker
but with not enough time to replace it with another one and get it up and running, i presented the bandido to the jury at the end of the year in the state it was.
and explained why it didn't work properly.
they understood the problem and i passed
so thanks for all your help (and the help from all the other people on this forum)

i'm planning on taking the bandido apart and rebuilding it in the summervaction
and this time i'll make sure i have a decent circuit board and the right components
I'll let you know how it works out when i get it finished (or if i get stuck again ).


best regards,
stijn

[Max]

hi max,

for some strange reason i got a mail today to tell me about the replay u gave me 2 years ago and i didn't see it here before, really strange .
anyway, i made the badido for a project in school almost 2 years ago and was not really good at electronics back then so i could not really figure out why it refused to work.
btw the guy in the shop where i got my components ensured me the TL062 was a decent replacement and wasen't gone mess with the desing
butt still the only way i could get a bleep was when i turned everyting to max and put a big piece of metal right in front of it.

after getting some help from a teacher we found out that the TL062 was in fact the problem maker
but with not enough time to replace it with another one and get it up and running, i presented the bandido to the jury at the end of the year in the state it was.
and explained why it didn't work properly.
they understood the problem and i passed
so thanks for all your help (and the help from all the other people on this forum)

i'm planning on taking the bandido apart and rebuilding it in the summervaction
and this time i'll make sure i have a decent circuit board and the right components
I'll let you know how it works out when i get it finished (or if i get stuck again ).


best regards,
stijn

Hi,
I see... yes... the TL062 is not good at BandidoII I checked them and was not good at all. Best is always TLC2262 on it or similar parts.

Let me know of progresses...when you'll start it again.

Kind regards,
Max