GOLDSCAN 5 SCHEMATIC QUESTION

[daverave]

The GS 5 schematic posted on this site is based on the original early GS 5 from what i see...personally i think the 4001 circuit is a good thing to have to stop any loud blair in your headphones...but its each to his own i guess.

[dbanner]

Gs5 pcb

I am working on gs5 PCB layout using sprint layout 6. It is almost complete. Will be posting it this coming weekend. I am leaving out the 4001 as its not necessary. Power supply will be on separate board. 4046 based vco audio(mickstv) will be on separate daughter board. I am trying to adhere to principles outlined in the following document about PCB design. Noise and inherent instability arising from layout is main concern. Any suggestions would be welcome. The design is throughole.

[eclipse]

Toss out sprint layout. Use schematic & pcb design software like diptrace, eagle.

[dbanner]

almost done. just need to label components

[Orbit]

[daverave]

Hi Orbit

i think the TX is between 100 - 120 uS

[Orbit]

No error with tx 100us but not bad a little more energy tx 200us .

[daverave]

Hi Orbit...how much total circuit current you drawing from the batteries at 200 uS TX ??? surely at 200 uS you will loose some depth on small gold.

[Jose]

A TX of 200 us, is not possible at the frequency of 3200, 3300 Hz, because the sample pulses of channel 2 are superimposed with the next TX pulse.
Also the power consumption would be very high.
Jose

[Orbit]

Hi Orbit...how much total circuit current you drawing from the batteries at 200 uS TX ??? surely at 200 uS you will loose some depth on small gold.

I have not noticed a loss of 1.8 grams concretely ! Otherwise I have to look around about spending where I wrote Consumption from 100us and 200us .. I'll see the notes tomorrow .Maybe I'm something twisted I did it two years ago ! I've been experimenting with various pulse widths maybe it's 800hz here,, I'll write tomorrow !

[daverave]

a few months ago when i built the first stage of GS 5 i set the TX width at 120 uS and transmit frequency at around 3 khz and my back emf was around 750v and my total circuit consumption at around 750 mA...if i increase the frequency control to around 3.3 khz then my consumption go's up to around 850 mA....at this rate my batteries will last only about 3 hours search time which is not good in my view. For me GS 5 should be built according to as near to spec as possible.

[Orbit]

a few months ago when i built the first stage of GS 5 i set the TX width at 120 uS and transmit frequency at around 3 khz and my back emf was around 750v and my total circuit consumption at around 750 mA...if i increase the frequency control to around 3.3 khz then my consumption go's up to around 850 mA....at this rate my batteries will last only about 3 hours search time which is not good in my view. For me GS 5 should be built according to as near to spec as possible.

With which voltage you supplied ? It's a little weird that much energy ?

[daverave]

supply voltage around 15v

[Ferric Toes]

Hi All,
My original GS5 had a current limiter originally using a couple of transistors and later the 337T negative regulator wired as a constant current device. This was largely so that you could use other manufacturers mono coils that had a much lower resistance than the ones I made. This limiter kept the mean current at 600mA whatever the weather.

Eric.

[daverave]

Hi Eric...i didnt realize that the 337T was a way of allowing different coils to be used with GS 5..the circuit i made at the time based on the geotech GS 5 schematic part 1...i was trying to make the front end circuit very compact to fit into a 50mm plastic tube and so maybe there could have been an error in my layout causing the circuit to draw 750 mA.