Janglebox Vero Issue

[kayrosso]

Built out a janglebox using the lm13700 layout and not getting expected behavior.

Getting a mis-biased type sound, with sound only kicking in with louder notes and decay sputtering out then abrupt silence.

Video here:


Pictures of top and bottom of board:

https://pasteboard.co/cJtpy3dKxLHk.jpg

https://pasteboard.co/gWTxF3OqTbZw.jpg


Pins 3 and 4 are giving me an expected voltage reading of about 2.92v with a .02v max differential between them. Pin 1 is 1.31v with attack at max and 1.20v at min.


Issue seems to stem from pin 5. Getting a voltage reading of .68v. My understanding is that the 220k resistor should be measuring 2.78v across but end at VB is 2.78v while end going to pin 5 jumper is at .68v.


Any ideas what might be the issue here?

[Lani]

I would run a knife down the board on the solder side in between the tracks. Would also make sure your getting no continuity where your breaks are. Soldering looks good so my guess is there is a hairline short in one of those two areas (in between tracks or breaks in tracks)

[mauman]

+1 to Lani's ideas, make sure all your cuts are truly cut, including the one in the green circle by pin 5. Also knife-blade the tracks, including the suspicious locations in the orange circles (but there are others.)