Rhodes Chroma Polaris

I checked all of the matrix with the Fluke.  Positive results!  After a fashion...

The right top board measured in the 3.7x M Ohms range - all of them.  The left top board had some crap in the connector or something.  I used canned air first and then some Deoxy D5.  Used the leads in a consistent fashion and they ranged from 306 - 363 M Ohms.  So, this is a good thing.

I had to trim the ribbon cables a smidgeon and checked if they were even across.  After the Deoxy, they went in a little more than before.  This was the replacement board for the one in it when I bought it.  I think there may have been some Q.A. issues sending that board out but I won't get into it here.

Further, broke a key but trusty old gorilla glue to the rescue!  

Reseated EVERY DAMN chip and jumper in that beast and lost 1 chip.  A non-CEM, good thing...   $2.95 for a replacement.

So, the ribbon cables check out so far, the key is fixed and playable and I've reseated the entire mutha...  I'll get that chip ASAP because it may not work otherwise, unless it simply cuts off one of my 6 channels.  Z207 clan...

Now what, boss?  Anything I can do with the chip missing or should I wait?

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, 4:53 PM
 
 
  
 
 
 
   
 
 
     
       
       
       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@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, 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@...>
 
  ------------------------------------
 
  
 
  
 
  ------------------------------------
 
  
 
  Yahoo Groups Links
 
  
 
  
 
  
 
      (Yahoo! ID required)
 
  
 
  
 
      chromapolaris-fullfeatured@yahoogroups.com
 
  
 
  
 
  
 
 
 
     
      
 
     
     
 
 
 
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