> When I turned it on again, all the panel LEDs lit
> and there was no sound. Unplugging and replugging
> the pedal and sustain switch jacks seemed to clear up the problem.

...

One of the most common reasons for this sort of behaviour is the 'reset
level' ("DC OK Threshhold") on the power supply. Over time the power
supply will age - and so it would not be unexpected that an adjustment
would be required, especially if it has been well used for many years.

If this level is a little low, it will most often manifest with some/all
of the LEDs being stuck on and the machine not working.

If this is the source of the problem, then it is something easy to
address (and is covered in the Service Manual, ref: Section 6 -
Adjustments and Checkout) [The service manual is available in both in
PDF form as well as through web page form at
http://www.rhodeschroma.com/?id=polaris ]

The whole manual is good to have - but if you don't want to download the
large file, here's the two para.'s that deal with the DC OK setting:

===================

DC OK THRESHOLD:
---------------

The factory setting for the DC OK threshold requires the use of a rather
elaborate test circuit; however, it is sufficient in the field to simply
back off on R17 to minimum (full CCW), then turn it clockwise until LED
CR10 lights. The nominal DC level out at DC OK (P3 pin 1, brown wire)
is +3V.

Late serial numbers use a different secondary board with a modified DC
OK circuit. ON these no adjustment is necessary or provided. The
nomimal DC level out at DC OK (P34 pin 1, brown wire) is +5V.

===================

Here's the link to the Adjustments section alone:

http://www.rhodeschroma.com/?id=polarisserviceadjustmentscheckout

Beyond the DC OK setting, it would also be recommended to go through the
full Adjustments and Checkout section - which will also confirm such
items as the DAC null - and will also ensure that the volume levels are
set up and memory is restored.

> I tried doing the adjustments listed on page 108 of the manual.
> But there is a problem with those directions. They instruct
> you to "turn the MASTER slider all the way up", and
> then to & quot;raise the MASTER slider until you
> hear the note just begin to bleed through". I don't
> understand how you can raise the slider any more after
> it is "all the way up".

The reference to Page 108 appears to be for the "Volume Offset"
adjustment in the User's Manual.

The text for this setting in the Service Manual is more clear:

http://www.rhodeschroma.com/?id=polarisserviceadjustmentscheckout#volumeoffset