Hello everyone,
Recently, I'm making a x0xb0x, and I have completed the VCO part. It seems that it has worked. I tested Pin1 and PIN3 of S1 with oscilloscope, and got these two waveforms, which should be correct.
However, when I went to the VCF part, I had trouble. It didn't seem to work. I couldn't detect any waveform at VR4. I didn't have high impedance headphones, so I used a speaker with a power amplifier, and there was no sound.
So I used the oscilloscope to test the pins of Q12 and Q22, and got the following waveform.
In DC, I could only detect a straight line, so I switched to AC.
Each pin of q21 can not detect the waveform, which is almost a straight line.
Voltage of each pin of Q12:
1 - 5.33V
2 - 9.59V
3 - 4.81V
4 - 9.59V
5 - 5.33V
Voltage of each pin of q22:
1 - 11.15V
2 - 11.68V
3 - 11.66V
4 - 11.68V
5 - 11.15V
Voltage of each pin of q21:
1 - 2.73V
2 - 2.15V
3 - 2.12V
4 - 2.14V
5 - 2.73V
The gap between q21 voltage and reference voltage is too large, so I took it down and measured q21 pad voltage as follows:
1 - 5.28V
2 - 11.64V
3 - 0.61V
4 - 11.58V
5 - 5.28V
By the way, I can't buy 2sc1583 and 2sc2291. I replaced 2sc1583 with pmp4201 and 2sc2291 with two bc337a.
This is my current situation. Who can help me?
How depressing! My VCF doesn't work all the time. Who can he
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- supercaby
- Posts: 4
- Joined: Mon Oct 05, 2020 12:12 am
- supercaby
- Posts: 4
- Joined: Mon Oct 05, 2020 12:12 am
Re: How depressing! My VCF doesn't work all the time. Who ca
This has been solved.
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Please be positive and constructive with your questions and comments.