[sdiy] Sequencer good (and bad) news update

[Peter Grenader]

Well, it seems I've fumbled the ball on the 2 yard line.

I've got everything wired up on the sequencer (including 46 lines going
through molex connectors - a lesson learned for not waiting for the proper
size breadboard and electing to do it on two) and everything works, - all
the direction controls, the pulse outs via IN4148s that I wasn't sure about,
hold, random, EVERYTHING except there is no output on either of the summing
amps at the very end of the signal flow.  D'oH!

Let me just focus on the final output summing amps here as I petition my
brethren for solutions.

I used a dual LM324 inverting amps in series for each of the stage outputs
to sum the voltages coming out of the pots and get them up to 0 to 12 volt
output.  Each op-amp pair is getting a signal from the pots, the correct
pots, yet none of the summing amps are passing a signal out of either the
final exit or from the output of the first series op- amp into the last.

This points to three things:  1) Either there's a wiring error, 2) the one
LM324 is a dud (two banks, two op-amps in series per bank, four op-amps
total = one LM324) -or- my design in this area is bad.  Highly likely.  Ever
more so in that both op-amp pairs are behaving exactly the same.

Here are the facts:

1) Unit runs off of ground and +12

2)  All of the outputs of the pots are functioning identically.  No bleed
from one bank to another, no grass on the signals, no dead pots, no pots are
effecting others.  They are doing exactl what I wanted/expected them to.

3)  the range of these pots are:  fully CCW= ground, fully CC= 1.2 volts.
Required range after summing and amplification is 0 to 12 volts.

Any suggestions any of you might have as to alternate summing amp design
would be greatly appreciated.  Then all I need is Grant to help me with a
tweek name for the beast.  Something like "Sequ-o-later" or something like
that.

Thanks in advance and humbly submitted,

Peter