madbeanpedals::forum

Projects => Tech Help - Projects Page => Topic started by: Droogie on March 23, 2014, 02:13:54 PM

Title: Sea Urchin Noise—FIXED!
Post by: Droogie on March 23, 2014, 02:13:54 PM
Built a Sea Urchin yesterday on a nice SMD board by Pickdropper and got significant noise on all repeats and continuous white noise with the delay pot at minimum. Not expecting pristine by any stretch, but there's something wrong. My voltages are good on the TL072 and 78L05.

On the 2399 I get 5 volts on pin 4, which should be 0; pins 5, 7 and 8 are also off significantly. I'm looking at C17, C18 and C19. R18 appears to be correct. Any place else I should be looking?

Thanks!
(http://www.madbeanpedals.com/forum/index.php?action=dlattach;topic=2832.0;attach=2213;image)
Title: Re: Sea Urchin Noise
Post by: muddyfox on March 23, 2014, 02:27:24 PM
I'll be watching with interest as I also have a nonfunctioning dbd build in my box of fail.

sent from my mobile device

Title: Re: Sea Urchin Noise
Post by: lincolnic on March 24, 2014, 04:41:58 AM
Pin 4 is a ground connection, right? Make sure you don't have your 9V shorting to ground somewhere.
Title: Re: Sea Urchin Noise—FIXED!
Post by: Droogie on March 28, 2014, 02:08:09 PM
I reflowed pins 4 and 5 of the PT2399 and just touched up the adjacent caps—when I hit one end of C17, the whole thing came off. I had a bad joint on the other side of the cap. Works like a charm now.