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