MOTM

I have recently seen indication of several MOTM-190 VCA kits being 'DOA' after 
building. The problem so far has been mis-reading the 15K resistors and the 75K 
resistor, and in 1 case mis-reading the 7K5 for the 75K.

It is quite difficult in most lighting conditions to decide between 15Ks brown 
band and the 75K's violet (purple) band.

Stooge Larry's Rule of Resistors: measure *every time*. A 2 second DVM check 
will reveal the correct value.

If your MOTM-190 doesn't work, check this first!

Paul S.

I always measure every resistor. Takes but a moment, and then you are sure.

Scott
===============================================
Paul Schreiber wrote:

> I have recently seen indication of several MOTM-190 VCA kits being 'DOA' 
> after
> building. The problem so far has been mis-reading the 15K resistors and 
> the 75K
> resistor, and in 1 case mis-reading the 7K5 for the 75K.
> 
> It is quite difficult in most lighting conditions to decide between 15Ks 
> brown
> band and the 75K's violet (purple) band.
> 
> Stooge Larry's Rule of Resistors: measure *every time*. A 2 second DVM 
> check
> will reveal the correct value.
> 
> If your MOTM-190 doesn't work, check this first!
> 
> Paul S.

I have a block of wood with two 4" pieces of stainless steel wire
(welding rod) set in at an angle about 1.5 inches apart. I clip the
ohmmeter leads to these, hold the body of the resistor in my fingers and
run the leads against the wires.  Takes a few seconds and eliminates
problems.

Also, the kits will have a Bill of Materials -- match the components to
the BOM.  I use a piece of styrofoam for all the non-semiconductor
components and write on the foam with a marker what the values should
be.  If there are supposed to be ten 1.5K resistors, I'm expecting to
see ten of them clustered around the "1.5K" written on the foam. If
there are not, I re-check everything.

30 minutes of sorting will eliminate many hours of frustration later
(although I only know this from hearsay -- never happened to me
_personally_ -- nope, never...).

> -----Original Message-----
> From: J. Larry Hendry [mailto:jlarryh@...] 
> Sent: Friday, November 12, 2004 10:25 PM
> To: MOTM List
> Subject: Re: [motm] MOTM-190 resistor swapping
> 
> 
> 
> > ----- Original Message -----
> > From: Paul Schreiber <synth1@...>
> > Stooge Larry's Rule of Resistors: measure *every time*. A 2 
> second DVM
> check will reveal the correct value.
> 
> I still do this always.  Seems like I often find something 
> that is not as it
> appears.  So many of the dang colors look the same anymore.
> 
> It may take a little bit of time.  But, it is a good investment.
> Larry
> 
> 
> 
> 
> 
> 
> 
> 
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> ----- Original Message -----
> From: Paul Schreiber <synth1@...>
> Stooge Larry's Rule of Resistors: measure *every time*. A 2 second DVM
check will reveal the correct value.

I still do this always.  Seems like I often find something that is not as it
appears.  So many of the dang colors look the same anymore.

It may take a little bit of time.  But, it is a good investment.
Larry

On Saturday 13 November 2004 07:20, Dave Halliday wrote:
> I have a block of wood with two 4" pieces of stainless
> steel wire (welding rod) set in at an angle about 1.5
> inches apart. I clip the ohmmeter leads to these, hold
> the body of the resistor in my fingers and run the leads
> against the wires. \ufffdTakes a few seconds and eliminates
> problems.

Great tip!

- Robert

> I have a block of wood with two 4" pieces of stainless steel wire
> (welding rod) set in at an angle about 1.5 inches apart. I clip the
> ohmmeter leads to these, hold the body of the resistor in my fingers and
> run the leads against the wires.  Takes a few seconds and eliminates
> problems.

Oh, I like that. That's much better than fiddling with test leads. Thanks!

I do the same routine of sorting the resistors first and sticking them in a
block of Styrofoam, grouped by value. Besides making the assembly go more
smoothly, this also helps me identify the hard-to-read values before I put
any of them into the PCB, thus reducing the chances of putting something in
the wrong location.

Incidentally, if anyone here remembers the old days in which I was
maintaining a diary about building my modular, I've made an attempt to start
doing that again. The latest entry is a quick summary of what I've built
since the previous entry (which was, um, about two years ago) and this
morning I put up some photos of a few MOTM conversions. The web site's at
http://www.studionebula.com

--Adam

--- In motm@yahoogroups.com, "Paul Schreiber" <synth1@a...> wrote:
> I have recently seen indication of several MOTM-190 VCA kits 
being 'DOA' after 
> building. 

On my little workbench, I have a small bright lamp.   I use a loupe, 
a jewelers magnifier to view the resistors in the bright light.   
Under that bright light and magnification, I can distinguish the 
colors very well.

As a non EE geek, I sometimes get confused with what the 75K and 7K5 
mean.   Before assembly, at each step in the instructions, I go 
through each resistor step and match up the part and write in it's 
color bands.   Then at assembly time I just grab up the resistor with 
those color bands and confirm with the loupe.  It seems to have 
worked so far.

Have fun.
Andy