Rhodes Chroma Polaris

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@yahoo.com
 [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