MOTM

I've just finished building a couple of Blacet Dark Star Chaos 
modules with Stooge front panels. Below are the details of some 
simple mods I made to them (in addition to the three Dave B. mods at 
http://www.hotrodmotm.com/ds_mods.htm). If you're building a DSC, or 
have already built one, these mods may be of interest to you.

1. I used a green Lumex LED rather than the one supplied with the DSC 
kit. It seemed a bit dim compared to my other modules. I changed R43 
from 1K to 330 ohm to get the brightness up to spec. (Keeners will 
note that this is the same value used in the MOTM-700 module to drive 
a green Lumex LED off a 5 volt source, same as the DSC.)

2. I made the "Continuously gate the Dark Star ON" mod but noticed 
that it rendered the Gate pushbutton useless. With nothing plugged 
into the Gate jack, the gate is always high so the Gate pushbutton 
has no effect (no problem there). However, with a signal plugged into 
the Gate jack, pressing the Gate pushbutton still has no effect if 
the signal driving the Gate jack is low (0 volts or negative). I want 
to be able to manually trigger the DSC by pressing the Gate 
pushbutton no matter what voltage is applied to the Gate jack. 
Fortunately, the solution is simply to add a diode (1N4148 or 
similar) in series between the Gate  jack and J5 on the PCB (anode at 
the Gate jack):

Gate jack --->|--- J5

Without this diode, the voltage appearing at pin 9 of U7 is (roughly) 
the midpoint between +5 volts and the voltage at the Gate input when 
the Gate pushbutton is pressed. Adding this diode blocks the effect 
of any low voltage on the Gate jack so that pressing the Gate 
pushbutton will still drive pin 9 of U7 high even when the signal at 
the Gate jack is low.