Delta Pulse

[okantex]

Thanks for reply
indded I am jsut hobby guy.
I can not read colours.
I measured 680 ohm ,which must be 680ohm on pcb .it was 6k8 .may it be reason for high power on 2k2 ,can it burn 2k2.
anyway forgive me forlate replies, I only can visit site weekends ,
okantex

[Great_Alex]

I finally finished my delta pulse .special thanks to AFT,KT315,HUNTER.

[Great_Alex]

after i built the delta pulse it works well , it could detect a 2cm coin at 32cm with 25 cm coil ,at first the meter gage when it was calm and away from metalic object was around zero when detect a sample coin the meter gage increase to positive side and when the sample metal removed the gage go to negative but after 1 or 2 seconds it go back to zero position and balanced whit out pushing zero key , my delta fall into ground when i was testing the unit and it damaged , i check all the parts pcb and resodering and finaly found the D9 diode was crashed , i replace the D9 , and all of the iCs after this work the delta seems to becomes healthy but now when the sample metal removed the gage doesn't go to negative , i check the uA meter but it's OK , i don't know which one of this kind response is normal ,also the depth of detection decrease a coin in 20 cm .

the zero button doesn't work like the tune of other detectors like PS2 or lorenz , is it normal ?

what's the main reason for RANGE knob ( 500K ) , when i increase or decrease it obvious change in detector response not happen, what's the advantage of range of between 2 sample ?

best regards

[1843]

the zero button doesn't work like the tune of other detectors like PS2 or lorenz , is it normal ?

best regards

Hi,

Deltapulse is a very high gain and lazy metal detector... I have the zero problem with it like the yours...
Try to reduce the gain and increase the sample delay.

Regards,
1843

[aft_72005]

Hi Great Alex
You built it compact, also nice box, maybe made in china.
My delta pulse didn’t has zeroing problem. It is work ,fine.
Let me study circuit …………….
Best regards.

[Great_Alex]

Hi

yes AFT, it's a china box and it takes a lot of time to find a way to how arrange the items in the small box .
i use a 800mah SLA battery and it's enough for me.

about the uA meter reading ,after moving the metal away from the coil does it go back to negative side of uA meter then balance and set to zero or not it's go back to zero immediately .?( i don't know what's the normal response)

the Manual Mode that modified by KT315 in schematic is working very good and Metal detector can reach to deeper targets ,and excellent for pinpointing.

[aft_72005]

Hi Great Alex
Remote trouble shooting is difficult, as you said, your detector fallen.
Please check pcb tracks and true connection, also all pot.
Seem as final stage opamp go to latch up, as 1843 said you reduce sens
pot.
Best regards.

[Pektro]

Hi,
I've got same problem as the 1843 describe on page 11 of this thread.
I can't find solution in this topic.
Signal at the output of D4 (pin 6 of LF356) looks wery bad.
I spent last few days trying to locate problem, and nothing found.
The coil shouldnt be the problem - I have checked few coils, with resistance 2-10 Ohm, and different inductance, and alyawys is the same.

1843, how do you solve this problem?

[Carlos]

Hello, can you try to solder in parallel with a condenser coil between 300 to 600 pf, and you can see that the image of the wave is normal and does not alter the sensitivity of the detector

Greetings

Carlos


Hola, puedes probar soldar en paralelo con la bobina un condensador entre 300 a 600 pf, y podras ver que la imagen de la onda se vera normal y no altera la sensibilidad del detector

Saludos


Carlos

[Noemio]

Hi Pektro,

First of all just a little stupid clarification: your device is not working properly, right?

I will try to test my (working) DP to compare results but I need to know where do you connect the ground clip of your probe.

Regards

Hi,
I've got same problem as the 1843 describe on page 11 of this thread.
I can't find solution in this topic.
Signal at the output of D4 (pin 6 of LF356) looks wery bad.
I spent last few days trying to locate problem, and nothing found.
The coil shouldnt be the problem - I have checked few coils, with resistance 2-10 Ohm, and different inductance, and alyawys is the same.

1843, how do you solve this problem?

[Pektro]

Noemio,
My DP have a serious problem with stability, with higher Gain setting is singing like a canarian. Also Sensivity is very bad, it needs about 10cm to detect pincers (with coil 20cm).

Ground clip of probe connected to (-) therminal of battery.

Best Reagrds

[kt315]

did not forget about a battery of capacitors on power supply? I use even more then are seen on the schematic... is it 10000 uF? seems it is connected not right... you must connect it to power supply FIRST, then connect wires to PCB - ! (I do not consider a switch here).

people will translate my answer on clear english

[Pektro]

Hi kt315,
Im using a 5600uF nippon sxe + 1000uF (unkown made) + 100uF Panasonic FC (low ESR), connected parallel.

Something interesting: output of D4, with unmonted T3 (bc557). Still not perfect, but looks better.
It is possible that T3 is source of problems?

Best Regards.

[Great_Alex]

I use one 10000uf 50V and 4700uf 50v in parralel to power suply , but they are connect in pcb after the main switch that i applied in (+) battery , is it differ ?when i turn the power switch off the detector shut down slowly cause of energy in the capacitors , when i turn the TX PULSE knob to maximum the detector goes deeper and a beezzzzzz sound hear from coil , i put a magnet near the coil and when i use high power the magnet jump away ( amazing test ) , i use the detector with 50% sens and 50% pulse width and everything is ok , but changed in way of showing thge meter after the detector dropped !!!
ok it's work stable .
how can we adjust the circuit for more depth with stable behaviour ?

if we use very long tx pulse width the detector depth become very better but the mosfet become warm but no so hot , which stronger mosfet could i use or can i use another IRFf740 in parallel ?

i use another coil socket in paralell to main coil socket only for putting and testing damping resistor .

[kt315]

It is possible that T3 is source of problems?

if it is good so not. T2 & T3 & neighbour is anti-overloading circuit. as you are aware the overloading is getting up on massive metal target near the coil. the sample pulse is MOVING at 'right' side of delta pulse - in the side of more less of delta pulse amplitude.

that is simple role of these T2&T3. you can certainly temporary delete them on testing.

what value of R5 you did solder of?