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Hey guys sorry I haven't replied for a while my laptop has died (blue screen off death) I am using my phone for now so I cannot use my oscope till its fixed I am going to shorten the lead it is just over 1m it is a dual core shielded cable with a foil wrap should I swap it for coax?
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Impulse for now just shortening it should help. Sorry to hear about the PC. It seems if it not one thing ,
it is another!
What do you intend to use this detector for? Salt water beach, relic, coin hunting?Comment
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I want to use it on the wet sand to find old coins rings ect. .
The delay trim has been set to 12 ohms (just over half way) the whole time I have just wound it to full and backed it off 10 turns this gives me 13ohms.Comment
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I assume you mean 12K ohms? Since this is a 20 Kohm pot half rotation would normally be 10 K but pot tolerances would make 12 K OK as a starting point.Originally posted by Impulse View Post
If it is 12k can you give me a 40106 waveform? Then try with the pot set to max resistance which should be close to 20 K ohm.
If your PC is still broken then an air test it both settings would be fine.Comment
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yes sorry i meant 12k, i will try and get my pc to work, i have shortened the wire and cable tied it down to a pole so it cannot move around i have the neutral and the shield on the neg side at both ends i cannot move it without it sending a false signal (beepbeepbeep). The cable is only 750mm long now i have tried the coil both ways which didnt help, why is this problem still here?
what pins of the 40106 did you want? pin 2?Comment
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Yes pin 2 and 4. Regards the noise with cable movement, I don't know for sure but it looks like your sampling circuit is not working correctly.We will try to troubleshoot this when we get your scope working.Originally posted by Impulse View PostComment
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heres the 40106 scope pic pin 2 and 4
hereComment
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40106 pin2 and pin4 is same - 45us has to beComment
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kt315 yer they are the same no matter the position of the delay trim it does not change only the amplitudeComment
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Impulse see you got your PC fixed. Good job. As KT 315 says these signals appear to be the same, pin 4 should be significantly delayed relative to pin 2. The pulses should also be about 4V high and 45 uS wide. See post 205. Your signals just show the spurious response which is apparently (but not desirable) for a Barracuda. See the first two pics for what it should look like.mthe pic delay -near- minimum shows what you have which is wrong. I would do two things
1. Look at post 210 and very carefully compare you board to the pics Ray so kindly provide. If you do not see any differences do 2.
2. Cut the link across the external delay pot connections and install a 10K ohm fixed resistor.
The
There is something wrong with this sample pulse generator and unless it is working correctly the detector wil work very poorly or not at all. Until we get this fixed we can not proceed. It is my hope this is the last remaining problem. The rest is just tweaks
BTW I forget can you get you old board to work? Also can you send a 5534 pin 6 trace of you new board with the shorter cable?Comment
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you do not have a delay making by C4 R17 (U4 12-13pins). bad you do not see that.Originally posted by Impulse View PostComment
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5534 pin6Comment
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a delay making? next to cap 4 and resistor 17? what am i not seing?Originally posted by kt315 View PostComment
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you do not see THE DELAY between THE signals (the samples' strobes).Originally posted by Impulse View PostComment
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