ARGUS MD 222 A - help with battery solution

[Harp]

Hello!
I own an older metal detector ARGUS MD 222 A, for which the previous owner said that there is a problem if it works for a long time to start the sound signal.
That still have not checked, because I wanted to thoroughly cleaned before the first use.
The device has a front measuring instrument, two buttons (on / strength and discrimination), and from below has a single pressure switch in two positions, which can be activated with the thumb - on the switch does not say anything.
PCB is spacious and has two opamp, only 4 of the electrolyte, a couple of capacitors, and about ten transistors.
The coil has a 4 wire.
I encountered another problem, which is that the unit operates on two 9V batteries, therefore, -9V-0- + 9V, and certainly I would like to To deal with this, say the same solution as in SurfPI negative voltage. If I put 8x1.2V AA batteries, can thus get -9V to output?

I would ask your expert advice and if anyone has any information, schematics, manual, etc, about the unit would ask him to put them here. Thank you!

Some pics

https://www.aukcije.hr/pics/330/3300...pg.768x0px.jpg
https://www.aukcije.hr/pics/330/3300...pg.768x0px.jpg
https://www.aukcije.hr/pics/330/3300...pg.768x0px.jpg
https://www.aukcije.hr/pics/330/3300...pg.768x0px.jpg

[ivconic]

Hello!
I own an older metal detector ARGUS MD 222 A, for which the previous owner said that there is a problem if it works for a long time to start the sound signal.
That still have not checked, because I wanted to thoroughly cleaned before the first use.
The device has a front measuring instrument, two buttons (on / strength and discrimination), and from below has a single pressure switch in two positions, which can be activated with the thumb - on the switch does not say anything.
PCB is spacious and has two opamp, only 4 of the electrolyte, a couple of capacitors, and about ten transistors.
The coil has a 4 wire.
I encountered another problem, which is that the unit operates on two 9V batteries, therefore, -9V-0- + 9V, and certainly I would like to To deal with this, say the same solution as in SurfPI negative voltage. If I put 8x1.2V AA batteries, can thus get -9V to output?

I would ask your expert advice and if anyone has any information, schematics, manual, etc, about the unit would ask him to put them here. Thank you!

Some pics

https://www.aukcije.hr/pics/330/3300...pg.768x0px.jpg
https://www.aukcije.hr/pics/330/3300...pg.768x0px.jpg
https://www.aukcije.hr/pics/330/3300...pg.768x0px.jpg
https://www.aukcije.hr/pics/330/3300...pg.768x0px.jpg

Without it's power supply schematic it would be tough to design most suitable power supply and replace present state with two 9v batteries.
But... from rich previous experiences it is to expect pretty common circuitry in there.
I don't think that 9v per rail is a must. Most probably the circuitry works on somewhat smaller voltages.
Also i assume the circuitry will be pretty much tolerant on somewhat smaller voltages, even if there is not some voltage regulating circuitry already involved.
Knowing this it becomes easier to deal with it. A symmetrical bench power supply would help a lot to test the circuitry and define most proper supply regime.
But also there are many ways to achieve symmetrical power supply from one single voltage source.
Metal detectors, especially older models (especially solid state), are pretty tolerant. I assume those two opamps are also from older series and can work in wider voltage range too.
There should be no harm if you try any of the existing simple solutions.
What i would do... i would obtain very affordable and easy obtainable dc/dc step up converter module based on XL 6009:
http://www.banggood.com/XL6009-Step-...-p-916222.html
and make it something like this:

At least to try the circuitry and test the voltage ranges.
XL6009 module is adjustable and you can use wide variety of batteries on it's input, than adjust the output voltage to desired levels.
I put there 7809/7909 voltage regulators but you can try the circuitry with 7808/7908 as well.
XL6009 should be adjusted to provide at least 20-24 volts at the output. One single 12v battery will do.
But that's in case the detector really needs a 2x9v supply, which i highly suspect.
If you inspect it's circuitry; you'll probably find out that it is operated by lower voltages. That will make your job even easier and at the end you will be able to use even smaller battery voltage at the XL6009 input.
There are other solutions as well, apart from mentioned XL6009.
But in any case you must "generate" voltage high enough to be able later to "divide" it on two equal halves needed here.
Many methods to do that.
Most critical part here is not how to properly divide the voltage but how properly to "generate" higher voltage from lower one.
Most common method to make symmetrical power supply from single source:
http://www.eeweb.com/blog/circuit_pr...etrical-output

[homefire]

My bet is the detector works on only 9V. One battery is for the detection circuit and the other for the Audio. That could be the Sound issue previous owner had.

HF

[ivconic]

My bet is the detector works on only 9V. One battery is for the detection circuit and the other for the Audio. That could be the Sound issue previous owner had.
HF

That could be the case too, you are right.
In that case job would be even easier.

[Xtrem]

its IB detector

[Harp]

Oh, really a lot of information landed on the forum, thank you!

Xtreme, which is the year of magazine released?
I do not understand in what way could affect the error, if one 9V battery runs detector and other audio?

Well, it looks like I have a lack of knowledge in general, so I'll take pictures of the PCB and perhaps along the way and learn something.The first time I mess with IB, and I believe that simpler than this scheme can not be found to learn.

[ivconic]

Oh, really a lot of information landed on the forum, thank you!

Xtreme, which is the year of magazine released?
I do not understand in what way could affect the error, if one 9V battery runs detector and other audio?

Well, it looks like I have a lack of knowledge in general, so I'll take pictures of the PCB and perhaps along the way and learn something.The first time I mess with IB, and I believe that simpler than this scheme can not be found to learn.

Try to take high-res photos of both pcb sides.
We can try to trace out the schematic from those photos.

[homefire]

I got a Whites PrizmII for $15.00 because it detected but no audio. Problems was the connector from the battery used for audio.

[Xtrem]

Oh, really a lot of information landed on the forum, thank you!

Xtreme, which is the year of magazine released?


.

Its about 1990, it is from a promotion book of the factory Wallfass ELECTRON "Ausrustungen fur Schutz und Sicherheit.23 Auflage"

[bernte_one]

hello Harp,

pls help us to redraw pcb, make some good photos pls

[bernte_one]

i contacted the Autor form argus md, will see if he can help us
shop is down since a longer period now, over a year ago or so i could buy the pulse detector from them
but i seems they sold last items over ebay in end of 2014,
we have Problem that most of the german legends end their buisness last years and get retired
as i know on of the People from lorenz, also at tb electronics - there is nothing new the last years but i wirte to thomas breuer and he told me that he is planning a new detector but nothing happen, alsopulsdetektor from Diethelm neyka is no more active, he restarted an new line of detectors but seems he had no succes
Wolfgang Schüler is also retired (as i think he was involved in Lorenz ) i got one book from him and some parts he had at home

[bernte_one]

big Problem is that it is not allowed to them to give away schematics of older Projects, because thhis stuff is still produced

[Harp]

PCB foto off both side in atachment

If need extra position or value, talk.
Battery blue wire is 0V, red +9V black -9V
Diode red is 4148, blue is 5V6 zener
I see that I must cleen up PCB from soldering.
IC is CA3140E and CA358E
CA3140E gets scratch with sharp objects in pins... seems to me like standard production?
Switch is two side push, green-green, and blue-white
All electrolite 100uF/16V
Transistor are all kind: BC212, BC308, MPSA12, BC238 and C9106

[bernte_one]

wow thats great, this is classic pcb design, before any pcb software

i think in 2 weeks ivconic has draw a halfe sized pcb from it
looks all very simple

here is another patent with ca3140 as metal detector but bfo
pictures in patent sheet are funny but typical for this time
https://www.google.com/patents/US4255710

[ivconic]

wow thats great, this is classic pcb design, before any pcb software

i think in 2 weeks ivconic has draw a halfe sized pcb from it
looks all very simple

here is another patent with ca3140 as metal detector but bfo
pictures in patent sheet are funny but typical for this time
https://www.google.com/patents/US4255710

I did it "on the fly" just for fun.
But... photos are not taken good, under the straight angle, so most probably there are mistakes in my draw.
Let's make this a team work (not that i am lazy, but i have lot of responsibilities in next period) and anyone interested may continue where i stopped...



Yes once we get 100% accurate pcb trace; i will pull out the schematic and later it will be piece of cake to draw new half sized pcb (even smaller, so as i see it).