The TP1 Waveform

[1843]

Hi,
In my HH2 when the 7660 is not installed, the waveform of TP1 is OK,
But when the 7660 is installed, the waveform changes.
I did change the 7660, but its result was the same.
Is it normal?

[1843]

TP9

The TP9 voltage is varying between zero and -1v at all the time (for no target) and every 2 seconds goes up to +3v and then the HH (opt2) makes a beep.

Why it does occur? and for solve it, what I must do?

Thanks for every help,
Best Regards

[Carl-NC]

I have no idea what's going on. Try removing R37 and see if TP1 cleans up.

- Carl

[1843]

I have no idea what's going on. Try removing R37 and see if TP1 cleans up.

- Carl

Yeah, when I remove the R37, TP1 is clean.

[bbsailor]

Try This

1843,

Put about a 10 ohm resitor in series with the coil to reduce the coil current draw and see if this changes the waveform problem.

What is the inductance and resistance of your coil?

If you are working inside, you may be picking up noise. In that case, you may want to make a 4" diameter coil with about 35 turns of wire just for test purposes. This will work better indoors and pick up less nearby targets.

bbsailor

[1843]

TP4

My HH's TP4 waveform has difference with the HH article's waveform.
Is it cause to changing the TP9 voltage?

Mine:


Carl's:

[bbsailor]

1843,

Where did you put the scope probes on the Hammerhead schematic when making the photo that you just posted?

bbsailor

[1843]

I put the scope probe to TP4 and its GND to the +VB.

[bbsailor]

1843,

Can you adjust R18 to obtain 0 V at TP4?

See the adjustment procedure in Carl's Hammerhead article.

bbsailor

[1843]

Yes

[1843]

Yes, I did adjust it to zero.

[bbsailor]

1843,

Does this adjustment of 0 V at TP4 make your waveform look like Carl's?

If not, look at the waveform driving the the gate of the MOSFET to see what it looks like. First look at the waveform across R6 to see that it is being driven by Q1, 0V to -VB and then check that Q2 is driving the gate of MOSFET Q3 with an adequate drive signal across R9.

bbsailor

[1843]

The waveform across the R6 is from 0V to -VB, But the Gate driver waveform is from -3V to -VB.
Is it OK?

[Carl-NC]

Yeah, when I remove the R37, TP1 is clean.

So it sounds like the value for either R37 or C11 is wrong. Double check the values you have.

Regarding the Q3 drive, -3v is a little low, should be more like -1v, but it should still be OK.

- Carl

[1843]

I removed them; their value was correct (10K & 1nF).

Carl,
I don't know why my HH TP4 has difference with your.
All the my HH problem depends to it
It has a maximum at 4V (or5V - depends on coil using) and a minimum at -4V and its remainder is at 0V.

https://www.geotech1.com/thuntings/s...33&postcount=6
Plase help me,
Thanks