Strangeness while testing the VCO... VCO'RLY?

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analogstatic
 
Posts: 25
Joined: Tue Feb 07, 2006 10:04 am

Strangeness while testing the VCO... VCO'RLY?

Post by analogstatic »

Hello all,

I've run into some uncertainty while testing my VCO and am curious to see if their was any advice on how to proceed...

I've correctly finished/tested the power supply and have it calibrated to 5.33V. I then soldered in all components for the VCO. Rather than soldering in the ICs directly, I soldered in sockets but this is a minor detail methinks.

So on to the testing... I have a power supply with positive/ground/negative leads. I also have an OLD Heathkit oscilloscope that I've used many times for testing other audio circuits.

I am fairly certain that every piece used for testing was hooked up correctly as I went through it several times, in order to be certain. However...

When I look at the scope I see nothing but a flat line DC voltage. When I apply the 2VDC this line jumps about 5V. I approximately the same voltage jump when I apply 3VDC/

I figured that since this oscilloscope is so old, I shouldn't trust what I'm seeing. I hooked the waveform switch up to a little 9V amplifier from Radioshack in order to hear the waveform. I can hear a quiet tone coming off of the waveform switch. I can also distinguish between the square and sawtooth waves. However, I can't hear any difference when applying 2VDC or 3VDC, which worries me.

Any advice on how to proceed? I'm hesitant to move on to the VCA when the VCO isn't 100% checked out. It seems like something is wrong, because I should see something on my scope and/or hear the difference in tone between 2V and 3V. Thanks in advance.

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brandon daniel
 
Posts: 160
Joined: Sat Mar 12, 2005 12:46 am

Post by brandon daniel »

o'rly?

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