TESORO GOLDEN SABRE

[zlatica]

Hello,

I don´t have milivoltmeter and I´m measuring voltage on pin 7 LF353. Minimum voltage on pin 7 is about 30 mV. Is it a good or no?

[Qiaozhi]

Hello,

I don´t have milivoltmeter and I´m measuring voltage on pin 7 LF353. Minimum voltage on pin 7 is about 30 mV. Is it a good or no?

???
If you don't have a millivoltmeter, how are you measuring the minimum voltage as 30mV?

[zlatica]

???
If you don't have a millivoltmeter, how are you measuring the minimum voltage as 30mV?

Mimimum range on my DVM is 20 V AC. 30mV is 0.03 V. I can´t to measure voltage below 10mV. Because I´m measurng voltage on pin 7 LF353.

[Qiaozhi]

Mimimum range on my DVM is 20 V AC. 30mV is 0.03 V. I can´t to measure voltage below 10mV. Because I´m measurng voltage on pin 7 LF353.

If you're measuring the signal at the output of the preamp, then (with perhaps 4mV residual voltage across the coil) you should get approximately 4mV * 50 [gain of preamp] = 200mV at the preamp output. You do not want to find the lowest possible null, as this will upset the ground balance and discrimination settings. Try reading the TGSL documentation that Ivconic produced, where he explains how to null the coil properly.

[zlatica]

If you're measuring the signal at the output of the preamp, then (with perhaps 4mV residual voltage across the coil) you should get approximately 4mV * 50 [gain of preamp] = 200mV at the preamp output. You do not want to find the lowest possible null, as this will upset the ground balance and discrimination settings. Try reading the TGSL documentation that Ivconic produced, where he explains how to null the coil properly.

Ok. Thanks Qiaozhi

[sukri01]

anyone got good tip how to hold the 4mv null when potting epoxy? the thing is its hard to gt close to 4mv.. once got it, hot glued it, then when epoxy cured, it would rise back to 100+mv.. a bit frustrated..

[der_fisherman]

Don't do it all at once, do say 75%, let it harden, correct and glue 10% more, let it harden, correct and glue another 10%, then let it harden, do the last 5%.......
I actually glue one coil completely and round75% of the second one, except for the part that overlaps the other....that gets glued in small stages, looking at the scope....
Its not perfect method by any means.....but it gets you closer......not that I am an expert, still VERY amateur.....
Hopefully someone knows an even better way!!

[Qiaozhi]

anyone got good tip how to hold the 4mv null when potting epoxy? the thing is its hard to gt close to 4mv.. once got it, hot glued it, then when epoxy cured, it would rise back to 100+mv.. a bit frustrated..

Leave an adjustable loop that you can use to get the correct null after the epoxy has cured. Then apply a thin layer of epoxy on top of the loop to complete the coil.

[paku]

who on this forum have recompile file for pic16f88 for vdi project
can share

[sukri01]

thanks der_fisherman and qiozhi.. ill try both method. that adjustbale loop comes from one of the coil wires yes?

[Qiaozhi]

thanks der_fisherman and qiozhi.. ill try both method. that adjustbale loop comes from one of the coil wires yes?

Yes. Simply remove a turn from one of the coils and use this as the adjustable loop.

[golfnut]

On some Ive tipped the resin in and observed it change. You can push one of the coil bundles thru the resin with a lolly stick to retune a little. Keep the phase, rather than tiny null. S

[paku]

TGSL Homemade PCB

[Jerry]

Very nice video! Congratulations on getting your TGSL working so well.

Jerry

[Fabian]

TGSL Edu small

Sukri01 asked me about a PCB for TGSL Edu I did a while, and I noticed that I had never posted. Here it is. Is the original design of Eduardo, only a little smaller and it works.

regards,

Fabian

TGSL EDU Small.rar