I have problems 04-2011

[Gerrit]

Hello I’m a newbie at this forum, I came from Holland and don’t understand everything.

I build the HH normal setup C1, build everything together inc. coil. The HH was detecting but the sound was not stable. So I change a few things with the information from this forum. Nothing helps, and then I change the IC 5 and 9 with type TLC555. Then I power up the HH, sounds like the same, I was checking the Tp and then from the Q3 came some smoke. I turning of the power and replace Q3, then power up and feeling the Q3, he came very hot, then power of. This with coil connected. Then I disconnected the coil and power up checking TP 1, very low signal, and then I replace the IC 5 with a new one, then checking the signal, signal likes oké. I hope.
Used Parts;
IC1 ICL7660SCPA
IC2 78L05
IC3, IC4 79L05
IC5, IC9 NE555 changed it with TLC555CP
IC6 NE5534P
IC7 HEF4066BP
IC8 TLC072CP
IC11, IC12 CD74HCT221E
Q3 IRF840
R11 680ohm

Power up the system with coil connected for a few seconds and no detection.

With the power on and disconnect the coil because the Q3 get very, very hot.

When I turn the R42 I hear nothing changing, Turn R34 I hear nothing changing.

The signals at the TP are not the same as the Fig. 21-30.

Now I lost completely my way, I doing something wrong? I don’t know what is must do first.

Can someone help me.


A few off my pics.

http://metaal.webnode.com/images/200...F0009kopie.jpg,

http://metaal.webnode.com/images/200...F0014kopie.jpg,

http://metaal.webnode.com/images/200...F0015kopie.jpg

http://metaal.webnode.com/images/200...F0016kopie.jpg

[Qiaozhi]

Hello I’m a newbie at this forum, I came from Holland and don’t understand everything.

I build the HH normal setup C1, build everything together inc. coil. The HH was detecting but the sound was not stable. So I change a few things with the information from this forum. Nothing helps, and then I change the IC 5 and 9 with type TLC555. Then I power up the HH, sounds like the same, I was checking the Tp and then from the Q3 came some smoke. I turning of the power and replace Q3, then power up and feeling the Q3, he came very hot, then power of. This with coil connected. Then I disconnected the coil and power up checking TP 1, very low signal, and then I replace the IC 5 with a new one, then checking the signal, signal likes oké. I hope.
Used Parts;
IC1 ICL7660SCPA
IC2 78L05
IC3, IC4 79L05
IC5, IC9 NE555 changed it with TLC555CP
IC6 NE5534P
IC7 HEF4066BP
IC8 TLC072CP
IC11, IC12 CD74HCT221E
Q3 IRF840
R11 680ohm

Power up the system with coil connected for a few seconds and no detection.

With the power on and disconnect the coil because the Q3 get very, very hot.

When I turn the R42 I hear nothing changing, Turn R34 I hear nothing changing.

The signals at the TP are not the same as the Fig. 21-30.

Now I lost completely my way, I doing something wrong? I don’t know what is must do first.

Can someone help me.


A few off my pics.

http://metaal.webnode.com/images/200...F0009kopie.jpg,

http://metaal.webnode.com/images/200...F0014kopie.jpg,

http://metaal.webnode.com/images/200...F0015kopie.jpg

http://metaal.webnode.com/images/200...F0016kopie.jpg

From your first image it looks like Q3 is permanently turned on.

Let's take this one step at a time ...
1. Have you checked all the power supply voltages are ok?
2. What does the signal look like at the collector of Q1?

Make sure you take all measurements referenced to ground (+ve side of battery).

[Gerrit]

Hello,

The power supply voltages are ok.

Picture of Q1 collector

http://files.metaal.webnode.com/2000...F0017kopie.jpg

[Qiaozhi]

Hello,

The power supply voltages are ok.

Picture of Q1 collector

http://files.metaal.webnode.com/2000...F0017kopie.jpg

Are you sure you have the scope set to 50us per division? From the image, it looks like you have approximately 5 divisions per cycle, which means a pulse repetition rate (freq) of approximately 4kHz. The HH design is supposed to have a range of 900Hz to 2300Hz.

Are you using the active pulldown or passive pulldown option for Q3?

[Gerrit]

I using the passive pulldown option for Q3.

http://metaal.webnode.com/images/200...F0020kopie.jpg

[Götz von Berlichingen]

The Time/Voltage Measurements are probably very wrong, because the red Knobs are not in the "calibrated" 3'o clock position.

[Qiaozhi]

I using the passive pulldown option for Q3.

http://metaal.webnode.com/images/200...F0020kopie.jpg

Is there a signal on the gate of Q3?

[Gerrit]

Hi, I had no signal at the gate of Q3, so replace both transistors Q1 + Q2. Now a have a signal to the gate of Q3, he works again. Thanks for the info.