Help with Q3

[mschmahl]

Hello. I have built the HH2 single tone option and programmed the pic with the HH2Option1.c. I have conect all pot´s and a single-coil (as described in Rev 1.5 HH1) Now my HH2 give a permanent tone and doesn´t react of a metall-target. Q3 get very hot. I have only a DMM to measure.
Can anyone help me?
What informations do you still need?

Thanks from Saxony

[muss2020]

bonjour

[waltr]

Very hard to trouble shoot without an O'scope.
Do you know some one that has one you can borrow?

Also, not sure which schematic and PIC code you are using. Please post a link to these here so we can refer to the same documents you are using.

some troubleshooting hint:
1) Remove coil but keep a resistor at R101 (damping).
Apply power- Measure all the Voltages from the regulators. Are you getting +5, -5 & -5D???
If yes go to #2.
If -5 & -5D but no +5 then either the PIC is not outputing pulses to N1 or the charge pump circuit is bad or connected wrong.
Check polarity of the diode.
Get the O'scope and check that the PIC is outputting the correct pulses (you can not do this with a DVM). If its a DMM and has a Frequency range then check N1 for the correct frequency.

2) Remove PIC.
With your DVM measure the Voltage at the Drain of the MOSFET (Q3). Should be -VB (MOSFET ON)without PIC driving N1.
Tie N1 to -5D with a jumper. Q3 drain should now be are 0V (MOSFET OFF). Remember Battery positive is 0Volt in this circuit.
If either test does not give correct Voltage then recheck the parts from N1 to the MOSFET gate.

[mschmahl]

Thank?s but it is a very old post (2011). I have build some other PI?s since than. I don?t have the PCB anymore.

[Qiaozhi]

I was just going to ask if you realized that the post you're replying to is 9 years old!

[waltr]

No I didn't see the date....
At least the question now has an answer...lol