My thoughts were along the same lines, but the IC's are pretty easy
(for me anyhow) as they were made to line up the same direction. I had
some of the via holes had not been flowed all the way through last
night, correcting that did not modify the behaviour.
I am going to run this thing the way I would as a crusty old avionics
tech (hmm...)
But as Paul mentioned earlier the place to check things out would be
the Sawtooth first, and I have this fear that I may have cooked one of
the nice custom Q's that came with the kit. The smaller one (Q2?)
really did not want to get soldered in correctly, and I may have given
it too much iron.
That is the place where I will start anyhow. Glad that the theory is
in there too, makes it much easier to figure out.
Now to hunt ebay for an O-Scope
Bruce
--- In motm@y..., mate_stubb@y... wrote:
> Chances are greater than 50% that your problem is something simple
> like a bad solder joint, or IC in backwards. I had two modules that
> had completely dead outputs when I finished them. The problem? Too
> much heat had caused the coax insulation to melt just enough to
short
> the output cable. I had to learn to modify my coax installation
> technique!
>
> Moe
>
> --- In motm@y..., bruce@s... wrote:
> > I have a question about the troubleshooting guide in the back of
> the
> > MOTM 300 instructions.
> >
> > The third check box has several lettered steps. Step (b) says to
> > check the VX voltage, and make sure it is close to +4.8V, and
> mentions
> > the right side of R3.
> >
> > Looking at the schematics, it looks like R3 is involved in the
fine
> > tune voltage, whereas R37 is closer to where one might find VX.
> >
> > Comments?
> >
> > Oh yeah, I have an MOTM-300 that is not playing nice at the
> moment.
> > All of the voltages seem to check correctly (with the exception of
> VX
> > as noted above), now it is down to verifying that all of the
> > components are in the right spot...
> >
> > Part of me is wondering about O-Scopes and if that might help me
> find
> > the trouble sooner. There is no sound at all out of the module,
> > except from the pulse jack, if I turn the coarse tune knob to just
> the
> > right spot, it outputs noise that can be changed by moving the PWM
> > pot. 8-)
> >
> > Wahoo! (translation: this should keep me occupied for the next
> couple
> > of nights)
> >
> > Bruce