Rhodes Chroma Polaris

Resistance is measured in ohms.

You never measure resistance in a circuit with the power on.
The meter uses its own current to measure the resistance.
Any current in the same circuit from the power being on will 
cause an incorrect reading.

I don't think there is anything wrong with the new panels.
More likely something else could be causing a short between those 
two signals.   But we haven't even determined that a short exists,
it's just a theory at this point.

As I said before, measure the resistance between other pairs of SWSTB signals
to see what the resistance measures (should be high)   then compare that with 
the two signals I mentioned.

Maybe you should download the manual for the meter that you are using and 
review how to use it for simple measurements?


--------------------------------------------
On Fri, 6/1/18, Tracy Barber adirondack_pc@... [chromapolaris] <chromapolaris@yahoogroups.com> wrote:

 Subject: Re: [chromapolaris] OK - I Have Diagnostics Now And They Are Weird
 To: chromapolaris@yahoogroups.com
 Date: Friday, June 1, 2018, 2:44 PM
 
 So, stick the lack lead on one and the red
 lead on the other?  What Ohms / Volts will I be looking
 for?  Anything above 0?
 
 The membranes are pretty tough now that
 Paul redid them.  I have to watch it though because
 they have been jiggled around a bit.
 
 OK, I see - high resistance. 
 check for high Ohms on the pairs.  Unless I was sold a
 bad brand new set of face "plates", they should be
 fine.  Each line in the ribbons are good, except one
 has a small piece missing.  Still 3/4 there.
 
 Try this with the power on?
 
 Since last message, I have reseated the
 connectors and have done so much with it I should be a whiz,
 but no - just a Dummy for Electronics.  Except for
 computers, which are close but not close enough.
 
 Tracy
 
 --------------------------------------------
 On Fri, 6/1/18, Bob Grieb bobgrieb@...
 [chromapolaris] <chromapolaris@yahoogroups.com>
 wrote:
 
  Subject: Re: [chromapolaris] OK - I
 Have Diagnostics Now And They Are Weird
  To: chromapolaris@yahoogroups.com
  Date: Friday, June 1, 2018, 8:50 AM
  
  
   
  
  
  
    
  
  
      
        
        
        What I would
 suggest is that you use a multimeter
  to see if there is an electrical
 connection 
  
  between the two signals that I
 mentioned.   You can measure
  between other SWSTB pairs 
  
  to see what the resistance should be
 (high).   I would say
  do not unplug the flexes from the 
  
  membranes, or do any cleaning or
 spraying until you have
  determined if there is a problem.
  
  If you find a connection between those
 two signals that
  shouldn't be there, then try to
 figure
  
  out where the short is.   But do
 your measurements first,
  especially since the flexes are 
  
  somewhat fragile and you don't want to
 mess with them
  any more than absolutely necessary.
  
  
  
  Ideally, you use a meter and an
 oscilloscope to make
  measurements that indicate
  
  where problems lie, then you change
 chips, fix traces, etc
  to fix the problem.
  
  
  
  Bob
  
  
  
 
 --------------------------------------------
  
  On Fri, 6/1/18, Tracy Barber adirondack_pc@...
  [chromapolaris] <chromapolaris@yahoogroups.com>
  wrote:
  
  
  
  Subject: Re: [chromapolaris] OK - I
 Have Diagnostics Now And
  They Are Weird
  
   To: chromapolaris@yahoogroups.com
  
   Date: Friday, June 1, 2018,
 12:58 AM
  
   
  
   Bob -
  
   
  
   I actually have them here. 
  
   Section 9 of the service manual
 has the pairs. 
  That's
  
   where I got the info, from the
 site.  You have a good
  
   idea, however...  I was looking
 at these but didn't
  
   come up with any way to do
 anything with them.  Your
  
   example would be "J" and "K",
 vibrato
  and pitch pedal, glide
  
   and rate pedal if you put all
 the cross overs together.
  
   
  
   So, you're saying check out the
 ribbon
  
   cables again for anything out of
 the ordinary?  That I
  
   can do.  Clean them with
 alcohol, yes?
  
   
  
   I sprayed the connectors with
 canned
  
   air and used a little Deoxy D5
 on them to clean them up
  
   already.  Made sure they were
 in and lined up
  
   properly.
  
   
  
   Unfortunately, I can't check the
 side
  
   that is connected to the face
 plates because they're
  buried
  
   under the material.  Also,
 they're brand new. 
  
   Sheesh...  I also did the "S"
 curve as told to
  by the
  
   video.   I sure wished
 they would've spent a few more
  $
  
   on real connectors.  You also
 can't get a swab in
  there
  
   to clean the contacts better. 
 I wonder if an alcohol
  
   pad would work?
  
   
  
   Tracy
  
   
  
   **** 
  
    
  
    
  
    If you go to this site, and
 scroll
  
   down to the bottom, you
  
    can see the connections to the
 front
  
   panel membrane
  
    switches.
  
    
  
    These are not shown in the
 service
  
   manual schematics.
  
    
  
    
  
    
  
   
  http://www.rhodeschroma.com/?id=polarisserviceschematics
  
    
  
    
  
    
  
    If you look at switches A and G
 you
  
   will see that one end of
  
    each is common, and only the
 other end
  
   is different.
  
    
  
    One connects to J9A-3 SWSTB4
 and the
  
   other connects to J9A-4
  
    SWSTB5.   If something
 is
  
   shorting those two
  
    
  
    signals together, such as a
 solder
  
   splash, or possibly a bit
  
    of the old membrane flex still
 in the
  
   connector, then when
  
    
  
    
  
    you press G, you could get an
 A. 
  
    A lot of other pairs of
  
    switches would also be joined
 by such
  
   a short.   I suggest
  
    
  
    
  
    you troubleshoot the front
 panel issue
  
   and get it resolved
  
    before trying to troubleshoot
 anything
  
   else.  A DMM
  
    measuring 
  
    
  
    resistance should help to see
 if there
  
   is some kind of short
  
    between those two signals.
  
    
  
    
  
    
  
    Bob
  
 
 
 ------------------------------------
 Posted by: Tracy Barber <adirondack_pc@...>
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