VCO / weird looking square wave
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VCO / weird looking square wave

by x0xjesus on Sun Feb 10, 2013 6:44 pm

I am building a new x0xb0x using kit from x0xsh0p and at the moment I am building VCO. I measured the sawtooth with oscilloscope and it looked fine. I then continued the build it, but when I measured square wave, it didn't look similar than the picture on building instructions (http://www.ladyada.net/make/x0xb0x/fab/vco.html) and the voltages were also different:

Image

The instructions say that that the Vpp should be about 4 volts, but I get about 13Vpp. What could be the cause for the difference? And should I first try to solve it, until I continue constructing the kit any further?
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Re: VCO / weird looking square wave

by x0xjesus on Thu Feb 14, 2013 6:16 pm

I found out the problem and I think I found a small error in the build instructions. In the instructions, there is no mention of installing R36 before measuring the square wave. However, if the R36 is not installed, the square wave will look like the picture I posted. When I put the R36 on the board, the square wave looked fine.
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Re: VCO / weird looking square wave

by antto on Thu Feb 14, 2013 7:04 pm

yeah, it won't work if Q8 isn't connected to 5.333V
We are here too: irc.freenode.net >>> #x0xb0x
..:: c0nb0x v1.00 ::.. http://forums.adafruit.com/viewtopic.php?f=7&t=29282 (new control app - win/osx)
VCO Tuning: http://forums.adafruit.com/viewtopic.php?f=12&t=24759 (do it the EASY way)
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