Memorial day is 05/25/2015 – Orders will ship out on May 26th. There will not be any deliveries or shipping on Monday. Any order placed after 11am ET on Friday May 22nd will not start to ship out until Tuesday May 26th.

troubleshoot VCO: no SAW, only SQUARE
Moderators: Altitude, adafruit_support_bill, adafruit, phono, mome rath

Re: troubleshoot VCO: no SAW, only SQUARE

by substyler on Fri Mar 11, 2011 3:00 pm

DjunaSaurus wrote:
SubStyler wrote:check the area around C11, C31, C32 (voltages across) Q24, Q25 and the solder joints at S1.
maybe one of your eletcrolytic capacitors is bad or soldered in a wrong direction?
if you try to get saw wave, IC23 is getting hot?


I triple checked and everything is soldered right. But I didn't solder C31 and C32 yet (the manual didn't say so), but that normally shouldn't have any effect on the saw right?

you're right. I did not know how far your build has gone at this time. I had the same problem recently and it was a faulty electrolytic cap... C11 to be exactly.
therefore my thought.
electronics consists to 80% of superstition and to 20% of fairy tales • DIY or die!

Posts: 419
Joined: Tue Dec 02, 2008 6:29 pm
Location: Göttingen, Germany

Re: troubleshoot VCO: no SAW, only SQUARE

by pattern9 on Sat Dec 15, 2012 2:45 am

This is for reference to the future builders.

I had this problem too.

No saw, only square. R105 gave me a loud pop on the headphones.

After completing the VCF i could hear both waves.
Posts: 2
Joined: Thu Nov 01, 2012 1:41 am

Re: troubleshoot VCO: no SAW, only SQUARE

by monoloco on Thu Apr 04, 2013 5:05 pm

so once again theres a vco completely build
but no saw just a square wave :?
all components triple checked... doesnt feel right to just go on there must be a reason why it doesnt work
any suggestions ??? please!!
"he always had a terrible much acid i assume"
Posts: 14
Joined: Thu Apr 04, 2013 7:52 am

Re: troubleshoot VCO: no SAW, only SQUARE

by antto on Thu Apr 04, 2013 5:29 pm

well, the square wave is made out of the sawtooth, which means it most likely works
i'd suggest continue forward and check the waveforms again later :wink:
We are here too: >>> #x0xb0x
..:: c0nb0x v1.00 ::.. (new control app - win/osx)
VCO Tuning: (do it the EASY way)
User avatar
Posts: 1416
Joined: Thu Apr 15, 2010 3:21 pm