e-licktronic Forum

I have completed nava and everything was working - except bassdrum. I could only hear the envelope, but if I touched the pcb I would hear the bassdrum. So I suspected some cold solder joint or bad connection at sil8 sockets or bad vias. So I reheated most of the solder joints and when I plugged it back in I think I have short circuited something from snare/bassdrum section against one of the regulators. Now I get no output at all (and regulator 1 gets pretty hot). Any ideas?

there is still +15v but instead of -15v I get -0.73v.

tomk wrote:there is still +15v but instead of -15v I get -0.73v.

You most likely have a short between -15V and ground. Your reheats probably created the short.
If your DMM has a continuity checking function, check continuity between any -15V and GND, it should beep, or the resistance would be very low.
Double check all your reheated solder.

As for your original problem with the envelope only, use the schematic and check the continuity of all connection inside the bassdrum part.
This is a tedious task.
I already had that kind of problem, and I basically had to use some wire to bypass the bad connection.

I never had a problem with Yocto PCB, it seems that the manufacturer is different for Nava PCB.

thanks, but I have unplugged IO board from nava and there's not -15v in the power supply section on its own so I guess I should replace regulators.

tomk wrote:thanks, but I have unplugged IO board from nava and there's not -15v in the power supply section on its own so I guess I should replace regulators.

Ok, be sure to check for shorts before reconnecting, otherwise you'll risk frying the new regulator.

thanks for your help. I've replaced 7915 and that solved the voltage problem. bassdrum had a bad via between r13 and r23 so now it's working too (board 1.0a). my only problem left now is last step tact switch going randomly on and off, can't find any bad trace, I'll try ordering a new one.

Does the behaviour change when you press or wiggle the tact switch?
If not it could also be a faulty shift register (ic100)

I found the problem. There was a bad connection between last step and scale switches. Thanks everyone.