Thanks to Dave and James so far.
I ∗really∗ appreciate the help! I ∗do∗ know how to set it up and have used
it effectively for many tasks, including past calibrations of a power supply
and another MOTM module. My problem probably can't be solved by the listers
(though I hope it can!) and I think it's that I don't have enough real-world
experience with it, and a mentor (or tutorial) to guide me through it.
I read the books, etc. and I find that if I were working on a refrigerator,
e.g., I'd be fine ;)
I just wonder for example, why my DVM reads 27 volts when it's set to Volts
DC and the probes are hanging, unconnected to anything? These are my
demons--the odd little things that aren't documented in books or instruction
manuals...
I somehow feel that if I understood that, I would understand why that
trimpot didn't do anything to the reading.
Paul--to your recollection, there's no "HEY IDIOT YOU HAVE TO PRESS THIS
BUTTON FIRST" button on the DVM you designed, is there? Power on, dial it to
DC Volts should be good enough, right?
David.
> -----Original Message-----
> From: Dave Bradley [mailto:daveb@...]
> Sent: Monday, August 02, 1999 12:04 PM
> To: motm@onelist.com
> Subject: RE: [motm] Hey, look at me, I'm a dumb-ass.
>
>
> From: "Dave Bradley" <daveb@...>
>
> Also, you have to set the meter to read either Volts DC or Volts AC,
> whatever you are trying to look at. Trying to read volts with the
> meter set
> to read resistance won't increase your sanity!
>
> Moe
>
> > -----Original Message-----
> > From: james holloway [mailto:jimh54@...]
> > Sent: Monday, August 02, 1999 10:53 AM
> > To: motm@onelist.com
> > Subject: Re: [motm] Hey, look at me, I'm a dumb-ass.
> >
> >
> > From: "james holloway" <jimh54@...>
> >
> > Generally, when reading voltages you want the black lead attached to
> > "ground". The coax shield braid is a good ground on the MOTM
> > stuff. the red
> > or Positive lead is then used to measure the various voltages you
> > want. Hope
> > this helps.
> > Jim
> >
> >
> > >From: "David Bivins" <david@...>
> > >Reply-To: motm@onelist.com
> > >To: "Motm@Onelist. Com" <motm@onelist.com>
> > >Subject: [motm] Hey, look at me, I'm a dumb-ass.
> > >Date: Mon, 2 Aug 1999 10:13:11 -0400
> > >
> > >From: "David Bivins" <david@...>
> > >
> > >O.k., it's time to admit it. I'm bluffing through this modular-building
> > >thing!
> > >
> > >That's right--Every one of my modules has worked perfectly after
> > I've built
> > >it, and that's because I'm extremely careful and don't do
> anything unless
> > >I'm very sure of what I'm doing.
> > >
> > >But here's the problem. I can't seem to figure out my DVM.
> I've read the
> > >manual, I bought another DVM book at Radio Shack, I've read a couple of
> > >introductory electronics books, but for some reason I can't get my head
> > >around a couple of things.
> > >
> > >For example: I was calibrating my MOTM-110 yesterday, and even
> without my
> > >probes touching anything (quit snickering in the back), I was reading
> > >something like 29 volts. Once I was "hooked in," I put the
> jumper between
> > >+15 and the jack (you know what I mean?), watched the meter, and
> > turned the
> > >trimpot. Nothing. No change.
> > >
> > >I feel like whenever I turn on the voltmeter for anything other than
> > >testing
> > >batteries, I'm in for a rollercoaster ride of frustration. I
> > quit using my
> > >B&K, which was supposedly a good instrument, because I thought
> it must be
> > >broken--I could never get predictable results. Now I have the
> Radio Shack
> > >DVM that Paul designed, and I'm just confused.
> > >
> > >Thanks for the modules, Paul! I had the most amazing groove
> > going yesterday
> > >with the ring mod/vca, sub-octave multiplexer, 420, an EG, an old
> > >Hewlett-Packard function generator, a 606 and a 303 (for the CV
> > out). Wow.
> > >I
> > >have never, ever, ever heard a synthesizer do that. My jaw just dragged
> > >around the floor for an hour.
> > >
> > >Anyway, if anyone has a pearl of wisdom about DVMs, please drop them my
> > >way.
> > >Luckily I don't actually need it as the modules work just fine
> and I was
> > >able to do the alternate (non-DVM) calibration of the 110.
> > >
> > >Take care,
> > >
> > >David Bivins
> > >Creative Strategist & Transistor Rhythmer
> > >Brandscape
> > >New York City
> > >212.285.2600.x103
> > >
> > >
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