Threshold Pot doesn't work

[Carl-NC]

That should work.

[h9361]

Hello
Dear Carl.
Please forgive me for my questions.
As you know, range of your TX-pulse width is 10-75us (R3). I'm going to increase the range so that be able to set it in 100us.
I saw crossbow schematic and realized that it has only changed value of C8 from 10n to 15n. According to crossbow, we will have 100us if its frequency is set to 1000pps.
Do you think i can reach to it with the change?
thanks.

[Carl-NC]

That should work.

You should understand that your questions are easily answered by reading the data sheets. The 555 timer is well-documented as to how R1, R2, R3, R4, and C8 affect frequency and duty cycle. The 74221 data sheet will also tell you how the R-C values affect delays.

[h9361]

Hello
Dear Carl
I have a question about power of HH1. First, my HH1 worked without any problem, but it shows suddenly an instability behavior.
I started to test its different points, finally i realized that my +5V is +1.5!!!
I changed 7660 and its IC2 (78l05) but my voltage still is +1.5!
Do you have any suggestion to check the problem?
Thanks

[h9361]

Hello
Dear Carl
Please check whether my calibration is true or not?!

1- Remove IC5, IC8, IC10 and IC11
2- Connect pin 1 of IC8 to ground (+ Bat)
3- Set R18 so that TP4 is maximum (4V)
4- Set R23 so that TP5 is 0
5- Set R18 so that TP4 is 0

Is true?

[surfdetector]

Hello
Dear Carl
Please check whether my calibration is true or not?!

1- Remove IC5, IC8, IC10 and IC11
2- Connect pin 1 of IC8 to ground (+ Bat)
3- Set R18 so that TP4 is maximum (4V)
4- Set R23 so that TP5 is 0
5- Set R18 so that TP4 is 0

Is true?

All of the build information is here:
https://www.geotech1.com/cgi-bin/pag...head/index.dat

[h9361]

All of the build information is here:
https://www.geotech1.com/cgi-bin/pag...head/index.dat

Thanks, but i read its article and all of it.
I'm trying to use Mr. Mickstv's Audio over my HH1.
But i have some instability in his audio. I checked my TP4 voltage and it will easily set 0, i also checked my form wave and it's OK and i have good reaction with coil.
I think my instability audio is because of TP5 or TP9. Now, my R23 has not any affect over pins 2,3 of IC8, so i set it center, its voltage varies under 0V.

[Carl-NC]

I changed 7660 and its IC2 (78l05) but my voltage still is +1.5!
Do you have any suggestion to check the problem?

It could be something is overloading +5. Try removing the opamps.

Please check whether my calibration is true or not?!

1- Remove IC5, IC8, IC10 and IC11
2- Connect pin 1 of IC8 to ground (+ Bat)
3- Set R18 so that TP4 is maximum (4V)
4- Set R23 so that TP5 is 0
5- Set R18 so that TP4 is 0

Is true?

No, for #4 you want to measure the voltage across IC8 pins 2 & 3 and adjust R23 until it is 0V.

[h9361]

It could be something is overloading +5. Try removing the opamps.



No, for #4 you want to measure the voltage across IC8 pins 2 & 3 and adjust R23 until it is 0V.

Thanks dear Carl.
I checked the voltage across IC8 pins 2 & 3, it's 2.5v and R23 has not any effect!
So, i set R23 in center (50R).

[Carl-NC]

You may have a bad opamp.

[h9361]

Is your mean TL072 or NE5534?
Do you think i can use AD797 instead of 5534?

[green]

I don't have a Hammerhead so probably shouldn't reply. Trouble shooting interests me so I'll try anyway. With all IC's installed and jumper between L1 and L2 removed. Record voltage between ground and test points with a voltmeter or scope, scope would be better to verify readings are stable(not fluctuating). +5V_____, -5V_____, TP4 with(R18 CW_____, R18 CCW_____, R18 centered_____). TP5 with R18 centered(R23CW_____, R23CCW_____, R23centered_____).

L1(Tx coil) should be removed also.

[h9361]

I don't have a Hammerhead so probably shouldn't reply. Trouble shooting interests me so I'll try anyway. With all IC's installed and jumper between L1 and L2 removed. Record voltage between ground and test points with a voltmeter or scope, scope would be better to verify readings are stable(not fluctuating). +5V_____, -5V_____, TP4 with(R18 CW_____, R18 CCW_____, R18 centered_____). TP5 with R18 centered(R23CW_____, R23CCW_____, R23centered_____).

L1(Tx coil) should be removed also.

Thanks dear green for your guiding.
I have no problem with TP4, my problem is only about R23 and pins 2-3 of IC8.
I will measure the voltages.

[Carl-NC]

Is your mean TL072 or NE5534?
Do you think i can use AD797 instead of 5534?

You said earlier that +5V was not working. Have you fixed that? If not, remove ALL the opamps and see if +5V works. If it does, plug in each opamp and see if one of them is bad.

Yes, the AD797 will work for the preamp.

[h9361]

You said earlier that +5V was not working. Have you fixed that? If not, remove ALL the opamps and see if +5V works. If it does, plug in each opamp and see if one of them is bad.

Yes, the AD797 will work for the preamp.

Thanks dear Carl and green.
My problem is solved. Unfortunately, my two 7660 has problem and can't generate +5V, so my HH1 worked unstable.
Now, my HH1 works very very nice and stable, tp4 is 0, pins 2,3 of IC8 is 0, TP5 and TP9 is 0. I checked the points with my voltmeter and mini O-scope.