Voodoo Main Discussion

[Qiaozhi]

Hi Good evening everyone, I will make a summary of the problems I had with this Voodoo Project, I assembled and tested the various stages of the circuit with positive results, and once all the components were mounted, and connected a temporary coil for the PI circuit, all it worked with acceptable audio, at one point the audio dropped barely noticeable, and I started having problems with the lack of +5 volts at the Tp15. Replaced the components of the power supply stage, nothing changed. Today I connected a 1k resistor between the input and output of the 78l05, the voltage +5 is back on the Tp15, but after a few seconds the LT1054 pulled out the famous magic smoke. Without the +5 volts I hear very low only the hum of the 555, instead with +5 the circuit works with barely perceptible audio. My question is where can I look for the faulty component in the audio zone. A thousand thanks.

Did you measure the current being drawn from U7, as I asked in post #1534?
Adding a 1k resistor between the input and output of U7 was a bad idea.

[dgm]

Hi Good evening everyone, I will make a summary of the problems I had with this Voodoo Project, I assembled and tested the various stages of the circuit with positive results, and once all the components were mounted, and connected a temporary coil for the PI circuit, all it worked with acceptable audio, at one point the audio dropped barely noticeable, and I started having problems with the lack of +5 volts at the Tp15. Replaced the components of the power supply stage, nothing changed. Today I connected a 1k resistor between the input and output of the 78l05, the voltage +5 is back on the Tp15, but after a few seconds the LT1054 pulled out the famous magic smoke. Without the +5 volts I hear very low only the hum of the 555, instead with +5 the circuit works with barely perceptible audio. My question is where can I look for the faulty component in the audio zone. A thousand thanks.

[waltr]

Never mind... I though I had issues with the LT1054.

Looked at my notes and see it was the +5V regulator, U7 that did not power output with more than a few chips installed.
A 1k Ohm resistor across U7's input to output fixed this.

[Carl-NC]

I would suspect a short circuit between pins 7 & 8.

[green]

Measuring resistance from ground to IC pins and other points on the circuit card looking for a low resistance can sometime find the fault.

[Qiaozhi]

Mr. George, I removed all the integrated from the pcb, I tried to connect the power supply, Tp15 read +05, then except I reinserted one at a time up to the U10 Tl072, inserting this integrated the +05 on the TP15 disappears. I checked the power supplies between 0V -5 on pin 4, and +5 on pin 8, they are correct. What do you advise me to do?
I meant that the TL072 chip works by changing it with a new same result.

The next step would be to measure the current consumption on the +5V line. Disconnect the output pin of U7 (78L05) and insert a current meter in the line. U7 should be capable of supplying 100mA before dropping out. If it cannot manage that value then the 78L05 is either fake or a sub-standard part.

[dgm]

Mr. George, I removed all the integrated from the pcb, I tried to connect the power supply, Tp15 read +05, then except I reinserted one at a time up to the U10 Tl072, inserting this integrated the +05 on the TP15 disappears. I checked the power supplies between 0V -5 on pin 4, and +5 on pin 8, they are correct. What do you advise me to do?
I meant that the TL072 chip works by changing it with a new same result.

[Qiaozhi]

Hi Good morning Mr. George, the first time I removed the R48 resistance, the MD had an acceptable auduio, after several tests it lowered becoming barely noticeable. Could it have any meaning? And still the cip still has the firmware 1.0 loaded by Endy, could it have some responsibility? Thanks and sorry again for my questions.

The only way you're going to trace the cause of this problem is by employing logical fault finding. Trying to guess where the fault is invariably doesn't work. Version 1.0 of the software has nothing to do with the loading issue on the +5V line.

[dgm]

Hi Good morning Mr. George, the first time I removed the R48 resistance, the MD had an acceptable auduio, after several tests it lowered becoming barely noticeable. Could it have any meaning? And still the cip still has the firmware 1.0 loaded by Endy, could it have some responsibility? Thanks and sorry again for my questions.

[Qiaozhi]

In that case the LT105 appears to be working. There must be something loading the 78L05.

[dgm]

On the cathode D6 11,7 volt.

[Qiaozhi]

Hi Mr. Carl and Mr. George good evening, as promised I carried out your suggestions, without the R48 I tested the TP9 as per file n.1, then I tested the collector of transistor Q5 as per file n.2, last I inserted the R48 and tested the manifold of the Q6 as per file n.3. I changed the 79l05 - 78l05 - Q5 and Q6, but the result does not change, on the TP 14 I read -5, and on the TP15 +0.85. The 79l05 heats up and the 78l05 no. I don't know where to look. Thank you for your patience.[ATTACH]55862[/ATTACH][ATTACH]55863[/ATTACH][ATTACH]55864[/ATTACH]

If you remove the 78L05, what voltage is present on the cathode of D6?

[dgm]

Hi Mr. Carl and Mr. George good evening, as promised I carried out your suggestions, without the R48 I tested the TP9 as per file n.1, then I tested the collector of transistor Q5 as per file n.2, last I inserted the R48 and tested the manifold of the Q6 as per file n.3. I changed the 79l05 - 78l05 - Q5 and Q6, but the result does not change, on the TP 14 I read -5, and on the TP15 +0.85. The 79l05 heats up and the 78l05 no. I don't know where to look. Thank you for your patience.

[Qiaozhi]

Hi George, was there any reason why you used the oled display on the nano version vs. the lcd display in the original version?

If you look at the DipTrace schematic for the Arduino Voodoo adapter you will see that the connections are already there on D6 to D11 for the LCD.
I just wanted to use an OLED as an alternative. You can easily change the code to use the LCD if you desire. In fact the LCD is arguably easier to drive than the OLED, and may even be faster since it uses a 4-bit parallel connection instead of SPI.

[yatahaze323]

Hi George, was there any reason why you used the oled display on the nano version vs. the lcd display in the original version?