MOTM

Today I'm hearing my MOTM for the first time.  The only mistake I made was 
swapping the FM1 and FM2 pots on one of my 420 filters (easy to correct).  
Everything else in my blue case seems to work fine, except the behavior of 
probably the simplest module (MOTM-700) is strange.  I can plug in an LFO, 
VCO or EG and watch the LED go from red to green based on the CV input.  But 
I have to set the knob/switches down to between -4 and -5 to see that happen. 
 With no cable in the CV input, I can't turn the switch and see the LEDs flip 
as the manual indicates.  There are no adjustments on the board.  Both 
channels behave exactly the same.  It does switch between two different audio 
inputs and therefore seems to function.  It almost seems like the values of 
the pots are wrong yet they match the manual.  Has anybody seen this problem? 
 If not, I'll have to troubleshoot it.  Thanks.

-Elhardt

Since both channels behave the same, I might suspect
the regulated reference voltage (12 V+ and 12 V-)
supplied by U6 and U8.  Check the voltage present at
the each end of the pots.  If I am doing the math
right, you should have about +5.1 VDC on one side and
-5.1 VDC on the other side.  If you don't have that,
check your regulators U6 and U8.  Are the inserted
correctly?  What is the voltage on the ouput pins?
Larry

--- elhardt@... wrote:
> Everything else in my blue case seems to work fine,
> except the behavior of probably the simplest module
> (MOTM-700) is strange. ....snip....

> But I have to set the knob/switches down to
> between -4 and -5 to see that happen. 

>  With no cable in the CV input, I can't turn the
> switch and see the LEDs flip as the manual 
> indicates.  There are no adjustments on the
> board.  Both channels behave exactly the same.
> -Elhardt


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Did you forget the little jumpers on the cv input jacks from ground 
lug to normalling lug?

Moe

--- In motm@y..., elhardt@a... wrote:
> Today I'm hearing my MOTM for the first time.  The only mistake I 
made was 
> swapping the FM1 and FM2 pots on one of my 420 filters (easy to 
correct).  
> Everything else in my blue case seems to work fine, except the 
behavior of 
> probably the simplest module (MOTM-700) is strange.  I can plug in 
an LFO, 
> VCO or EG and watch the LED go from red to green based on the CV 
input.  But 
> I have to set the knob/switches down to between -4 and -5 to see 
that happen. 
>  With no cable in the CV input, I can't turn the switch and see the 
LEDs flip 
> as the manual indicates.  There are no adjustments on the board.  
Both 
> channels behave exactly the same.  It does switch between two 
different audio 
> inputs and therefore seems to function.  It almost seems like the 
values of 
> the pots are wrong yet they match the manual.  Has anybody seen 
this problem? 

>  If not, I'll have to troubleshoot it.  Thanks.
> 
> -Elhardt

mate_stubb@... writes:

>>Did you forget the little jumpers on the cv input jacks from ground lug to 
normalling lug?<<

That was a good suggestion.  It sounded like that might have been it, but I 
checked and they are there.  In fact if I just insert an unconnected plug 
into a CV jack, the LED turns green.  There is some info in the manual about 
what voltages I should be seeing on certain pins on the chips.  I'll have to 
check that out.  The module basically works, it's just that the knobs seem 
way off and don't behave like the "Preliminary Check-Out" in the manual.

-Elhardt