[sdiy] Re: Help! Fatman problems!

[Grant Richter]

While it is a huge pain in the a$$, troubleshooting is actually where all
the learning occurs. A recent article on brain function has stated that the
most long term learning occurs by trial and error. In other words, they now
have some evidence that learning by trial and error produces the longest
lasting memory engrams.

I suppose this makes sense from an evolutionary stand point. Failure has a
metabolic "cost", so each failure raises the "cost" of learning. Once the
solution is found, the brain stores that information by the most long term
method in order to maximize return on the metabolic "cost".

>From an emotional standpoint, it is unfortunate that lessons learned most
painfully are learned most thoroughly.

Having spent countless hours troubleshooting my own solder bridges,
transposed pins, misread numbers and other blindingly simple errors, I have
a simple piece of advice: Make yourself as physically comfortable as
possible during troubleshooting. Eat a snack (after washing the lead off
your hands), open a window for fresh air, take frequent breaks, walk around
for exercise. This MAY have the practical result of providing fuel and
oxygen for the intense metabolism of the brain during problem solving.

I don't claim any factual scientific basis for any of this speculation, I
have just noticed I troubleshoot most efficiently when my body is
comfortable.
> 
> I had a bit of a breakthrough yesterday. Previously I mentioned that the DAC
> tuning pot has no effect on the pitch. When I turn the Fatman on and, using
> the headphone probe, listen to R56 (VCOs 1, 2 and 1&2), rotating the DAC pot
> has no effect UNTIL I send a note through to the Fatman via midi. After I've
> done this the pitch can be tuned using this pot!
> 
> So, it appears that everything up to the VCO mix pot is working! I guess the
> next thing is to check the VCF section and find out where the signal is
> failing. I'll check the voltages around the Power Supply section and let you
> know what the findings are.
>