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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