> From: Mario
>
> Please May you help me to understand why
> my Polaris , when turn on, after 15/20 sec it became frozen,
> and all push buttons do not respond , it seems that the
> sliders works good , when it start to froze!
>
> This froze , start with last note continuing to play , and
> then if I try to change memory / patch the push buttons
> starts slightly not to respond , till everything stop, and
> even all push buttons don't respond !
>
> Few days ago VCO 1 played with a fast glide , and I ordered a
> new chip CEM3374 .
>
> I really do not know what to do ! Please May you give me some advice ?

Are you saying that it fails gradually? Most freeze ups happen suddenly
and all at once.

The first thing to try on any old piece of electronic equipment is to
check all the connectors.
Open it up (with the power off) and unplug and plug all the connectors
(except the battery one, if you want to keep your memory). If the
integrated circuits are in sockets (most Polarises have sockets), you
could also try pressing on them to make sure they're properly seated.

It's also possible that the EPROMs are fading, since they're 30 years old.
This would cause the CPU to occasionally read a bit incorrectly, causing
it to strange things, or even crash. The solution to this is to erase and
reprogram the EPROMs, which can be done by anyone who has an eraser and
programmer. The hex files are available at the rhodeschroma.com web site.

Another frequent issue, if you have the old power supply, is the DC OK
threshold adjustment. But if this is set improperly, it should freeze the
Polaris instantly, not gradually. You can read about this in the Service
Manual, also available at rhodeschroma.com, on pages 3-22 and 6-1.

--

Ciao, Paul D. DeRocco
Paul mailto:pderocco@...