MOTM

Jesse,

Re check the 300, you must have a short on the power rails
somewhere on that module. Plugging it in with the frame
powered up would not normally cause a problem of that
nature. That is why you have practically nothing on the 5V
rail.

Graham

On 31 Jul 2009, at 03:49, spacebardubs wrote:

> Hey y'all
> I'm new here and this is the first post I've made, so Hello.
>
> I just built a bunch of MOTM modules, all of which work great,  
> except for one boneheaded move I made. I accidentally plugged in one  
> of my 300 VCO's to the power supply while it was on. And it arced  
> and started smoking. I was pretty sure that it was U6 that was  
> smoking, so I replaced it. Unfortunately it's not going to be that  
> simple and I am now officially stuck.
>
> I did all of the troubleshooting tips in the manual and have ended  
> up with some very suspect voltages. At L1 I have -15V, but at L2 I  
> have only +.9V.
> In keeping with the list to check in the maunal:
> a. Pin 1 of U2 should be close to +5V. I have +0.15V
> b. VX should be close to +4.8V, I have nothing at all.
> c. The left side of R37 should be near +0.32V, I have +0.05V
> d. VREF on the left of C15 should be +5V, I have +0.15V
> e. With a sweep of the Coarse knob, Pin 7 of U4 should range from  
> -8.3V to +8.3V, I get -2.13V to +0.11V
> f. With the same sweep pin 1 of U4 should range from -0.3V to  
> -14.2V, I only have a constant +.25V
>
> The other very strange thing is that when I plug this 300 in to try  
> and troubleshoot, it seems like it's somehow shorting out the rest  
> of the modules plugged into the power supply. My other VCO no longer  
> makes any sound and the LED on the front of the 101 stops. When I  
> take the defunct 300 out everything works fine again.
>
> Any tips as to how to proceed would be greatly appreciated!
>
> Thanks in advance.
>
> Jesse
>
>
>