seting up barracuda with oscilloscope

[gogi]

Hi. I made a cuda from silverdog, and a homemade coil of 10,5" 21 turn of 0,5mm wire. the cuda is working on stabilized voltage of 12V. I got an pc osciloscope max 20Mhz. Can I setup the cuda and what should i do? Becouse my problem is that There are two 20turn trimm, and dont know how to setup that. I can get something from the detector, but not good enought. I am turning the pots randomly and checking how it is working, well this is not the right way. I will apreciate very much if somebody have the patience to give me directions.
Thank you.

[FatBob]

Umm Did you look at this thread; http://www.geotech1.com/forums/showt...409#post171409

[gogi]

Umm Did you look at this thread; http://www.geotech1.com/forums/showt...409#post171409

yes i did it. but i have this multiturn pots. well thanks anyway i will get the right setup, and let you know. tnx.

[kt315]

gogi, how to get offset balance U1... desolder VT1.... set your voltmeter on output... turn the trimmer... set zero volt on millivolts range.... voila.
is it difficult??? not!

[gogi]

gogi, how to get offset balance U1... desolder VT1.... set your voltmeter on output... turn the trimmer... set zero volt on millivolts range.... voila.
is it difficult??? not!

It is not difficult. Tnx for instructions.

[kt315]

set delay trimmer in middle position, or slightly in low value side. not so hard to do this.
you need o-scope ONLY to tune the generator on 600 Hz. i got 100us PULSE WIDTH at once, did not see need to tune something for that.

[gogi]

Hi. I have a problem locating VT1 on the pcb, and the trimmer pots are 20 turn, but they are turning continuously, and i don't know where is the middle position, except if i desolder it. Here is the pic of the board, so please can you mark where is VT1.

[Qiaozhi]

Hi. I have a problem locating VT1 on the pcb, and the trimmer pots are 20 turn, but they are turning continuously, and i don't know where is the middle position, except if i desolder it. Here is the pic of the board, so please can you mark where is VT1.[ATTACH]38673[/ATTACH]

Turn your pot in one direction by more than 20 turns. At this point you must be at the end. Then turn it the other way by 10 turns. That's the middle. Simple really.

[gogi]

Yes, thank you.

[Toros]

Hi. I have a problem locating VT1 on the pcb, and the trimmer pots are 20 turn, but they are turning continuously, and i don't know where is the middle position, except if i desolder it. Here is the pic of the board, so please can you mark where is VT1.[ATTACH]38673[/ATTACH]

VT1 is a big transistor IRF. It stands right on the big capacitor.

[kt315]

Hi. I have a problem locating VT1 on the pcb, and the trimmer pots are 20 turn, but they are turning continuously, and i don't know where is the middle position, except if i desolder it. Here is the pic of the board, so please can you mark where is VT1.[ATTACH]38673[/ATTACH]

1. measure the resistance between edge pins of the pot ie full value, pin 1 pin 2 and pin 3 - you take pin 1 and pin 3.
2. stay on middle pin and one of edge pin, pin 1 and pin 2, either pin 2 and pin 3.
3. spin a shaft of pot and look the resistance value on your tester meter.
4. - before you would get 1/2 of full its value.
5. thats be sure the middle position.

[ionut_mtb]

why you need to desolder irf to set 0v null?

[kt315]

why you need to desolder irf to set 0v null?

1. if you do not have o-scope
1.1. desolder irf
1.2. measure and set the nulling
2. if you have the o-scope
2.1. not desolder irf
2.2. set nulling looking the pic on the your o-scope.
3. if 40106 is setting on socket
3.1. remove 40106 from the socket
3.2. no generation - irf is closed
3.3. irf is not needed being desoldered.
3.3. measure the nulling

is that clear for you?

[ionut_mtb]

1. if you do not have o-scope
1.1. desolder irf
1.2. measure and set the nulling
2. if you have the o-scope
2.1. not desolder irf
2.2. set nulling looking the pic on the your o-scope.
3. if 40106 is setting on socket
3.1. remove 40106 from the socket
3.2. no generation - irf is closed
3.3. irf is not needed being desoldered.
3.3. measure the nulling

is that clear for you?

yes,thankyou!