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--- In chromapolaris@yahoogroups.com, "David Clarke" <ac151@...> wrote:
>
> > 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
>