Silver Sabre Plus zero disc switch

[Math]

hi, i'm trying to work out how to fit a switch to my silver sabre plus that will drop it into zero disc motion mode for searching similar to the original sabre but i have very basic knowledge of electronics and hope someone can help

i have attached schematic posted by Sean in earlier thread and added 2 points A and B where am guessing switch needs to be across?

[Math]

i am also thinking of fitting a pot in this circuit to give a second discrimination mode at a lower level for iron, would this be possible?

[Sean_Goddard]

YEs it IS possible. i'll have a god in the next two weeks and post the mods in this thread.

[Math]

thanks Sean, that's great

[Unregistered]

yaawwwwn still waiting.

[Unregistered]

Hello,

Hello,
Can someone post pcb view,and picture with all elements?
Please

[Qiaozhi]

hi, i'm trying to work out how to fit a switch to my silver sabre plus that will drop it into zero disc motion mode for searching similar to the original sabre but i have very basic knowledge of electronics and hope someone can help

i have attached schematic posted by Sean in earlier thread and added 2 points A and B where am guessing switch needs to be across?

In order to switch between discriminate and all-metal mode (i.e. no discrimination) you will need to put the switch somewhere else. The points you have indicated in the circuit will not produce the result you are expecting.

As you can see from the schematic, there are two separate channels - GEB (ground exclusion balance) and DISC (discrimination). GEB is the top channel and DISC is the bottom one. I would suggest putting a switch in series with the two 1N4148 diodes that are connected to pin1 of the LM393 comparator.
Have a look at the schematic for the Turbocharged Rimatron 7MX. This is the same facility that I added there.

[ivconic]

Very Nice!

I made 2 S.Sabres according this schematics.Works very good. A bit worse that G.Sabre but yet excellent. Note: pinpointing mode is very good, much better than on many other detectors! I salute this!
Regards!

[Sean_Goddard]

OH YAWN, it's a troll from UKDN

Hey unregistered, go Yawn somewhere else "Bloneg mwnci fachgen sy'n gael rhyw efo defaid". If you don't have valid input to this forum then go back to UKDN, it's full of people like you there, you should have a lot of fun.

I've now found 10 minutes to look at this and I think, though I bet Ivconic points me out to be wrong , that if you look at the schematic, at the bottom left side there is a 5.1K resistor, try putting a 1K resistor on a simple on/off switch across it.

I haven't tried this but if you look at it, it's part of the phase shift circuit for the discriminate and when the control is set to minimum, there is a residual shift due to this resistor, thus, reducing the value of this will cause less of a residual shift and so lower the "minimum discriminate" level...IN THEORY.

You CAN try values as low as 470R but NO LOWER as this will cause problems with the phase shift circuit, due to the design you can NEVER have true zero disc only very low levels.

Let me know how this works please.

[Sean_Goddard]

OOPS!!

Just in case it wasn't clear and I have to confess I can sometimes be an ignorant git by assuming people write good inglish like wot I does, and forgetting this is a multi national forum .

SORRY ALL, no offence intended.

Anyway, what I MEANT to say was.. Connect a 1K resistor in SERIES with an on/off swithc, THEN solder the whole lot in PARALLEL with the 5.1K resistor. Give that a shot, should work OK.

[Math]

thanks thats great i'll be trying this soon &post up how it goes