Full m/lab SD2000 schematics

[Anis]

Hi Anis,

Litz made with 36 strands of 0.2 mm enamelled wire would be perfect for what you want for a Mono coil it is what I use.

Regards, Ian.

Hi Ian, please can you specify the outer ID in AWG or in mm for this type of wire? it would very helpful for my search ebay.

Thx
Anis

[IBGold]

Hi Anis,

What you are looking for is Litz with 36 strands of 32 A.W.G or .2 mm making the overall 16.55 A.W.G good luck it is hard to find.

Regards, Ian.

[ghaj]

A question about low battery cct on the sd-2000 schematic

Hi there every body,
Does any body know how the low battery CCT in SD2000 is supposed to work?
I have wired the schematic on breadborad. As +VB voltage goes lower than 5.75v LED starts lighting. But in SD2000 user manual it has been mentioned that LED must flash on low battery.
As you can see on the schematic attached, LM393 Comparator-A goes low on battery voltage over 5.75v and goes high otherwise (having in mind that output is open collector). After that, Comparator-B has its non-inverting input connected to +Vb. It seems a little weird. How is the LED going to flash (or blink)? Does any body know about the frequency of flashing of the Low battery LED or how the circuit is going to do that?
Thanks.

[waltr]

Just put that CCT in LTspice and it does what you observed.

[ZED]

Well i did exactly that and it didnt work,discovered there is a trace missing from pin 5 to the junction of the two 100k resistors to the right of the IC,plus the 1nf cap on pin six is a tantalum which looks like a 1uf cap.
With out knowing what the chip is its difficult to get the cct to work in spice,it looks like the 1 uf cap loads the output on pin 1 when it wants to go high as a result of a low battery causing the following stage to oscillate.....i may be wrong.

As a foot note the proper battery voltage is above 6 volts,at 5.8v or below the led will flash at a freq of about 1hz.

[waltr]

Thanks ZED.
I though probably the schematic was missing connection and/or wrong value.
I simulated with an LT1017 which is open drain but has a large value internal pull-up. The older LM393 is a different beast.
The LED may also be involved.

ghaj,
Does the actual circuit work with the changes ZED listed?

[ghaj]

Hi there,
using the original schematic () ---> No flashing LED!!! The LED lights steady.
Modifying circuit to schematic (As ZED suggested) () --> Flashing LED
Changing the cap to 100nF in modified schematic results in ---> Flashing faster.
Thanks to ZED and Waltr.
I have built up the circuit on breadboard and I have checked both schematics. I have taken movies in .mp4 format but I could not upload it as it says invalid file .
Although it does not affect the Detector performance, but at least corrects the schematic.
Regards,
Ghaj.

[ZED]

Update on schematic for the low battery cct

See the pic below for the changes made to the low battery cct,will see if i can update the original schematic as well.

[Mechanic]

See the pic below for the changes made to the low battery cct,will see if i can update the original schematic as well.

While you're at it, I remember someone saying that the pin numbering of the bas16 diode was wrong as well.

Cheers Mick

[ghaj]

Hi there ZED,
I tested your updated schematic for Low battery cct (with LM393 IC and 1N4148 diode) on bread board and it is OK. The LED started flashing.
Thank you.

[ZED]

Nice job ghaj ! i wasnt sure if the cct would work with a 393,that chip was one of the few chips on the 2000 board that i couldnt figure out...well done !

Thanks Mick ! i think i may have grabbed the wrong diptrace model,um could you be so kind and tell me which is pin one on a smd resistor....

[dbanner]

Hi there ZED,
I tested your updated schematic for Low battery cct (with LM393 IC and 1N4148 diode) on bread board and it is OK. The LED started flashing.
Thank you.

It's a handy little circuit. I like it.

[Andrei]

Hi! How to connect LM13600? Pin 1 and 2 not connected? Pin1 connect to collector BC857? Pin 12 and 16 too not connected?

[Mechanic]

Nice job ghaj ! i wasnt sure if the cct would work with a 393,that chip was one of the few chips on the 2000 board that i couldnt figure out...well done !

Thanks Mick ! i think i may have grabbed the wrong diptrace model,um could you be so kind and tell me which is pin one on a smd resistor....

When you look at the resistor and the writing is the right way up, pin 1 is on the left! Make sure the current goes through the right way otherwise it will increase the current!!

Andrei, the connections around the LM13000n are correct. They look odd, but that is how they are and it works.

Cheers Mick

[Andrei]

When you look at the resistor and the writing is the right way up, pin 1 is on the left! Make sure the current goes through the right way otherwise it will increase the current!!

Andrei, the connections around the LM13000n are correct. They look odd, but that is how they are and it works.

Cheers Mick

Thank Mechanic! https://youtu.be/S1s6D3uFmmA. What could be the problem? Coil single core ~ 0.8mm wire is not shielded, maybe there is a problem in it?