Rhodes Chroma Polaris

> From: pterodactylrecords
> 
> My Chroma Polaris get really hot just stitting there. When 
> turned on I play it occasionally during the session after a 
> good while it gets quite warm where the heat sink is and the 
> keyboard OS eventually crashes. In a hot room ( summer , 
> lights, etc.) the crash happens sooner. Usually no sounds are 
> lost but I can't really use it further until after it has 
> been shut off and has cooled down. 
> 
> Any ideas as to what is going on? Improvements or repairs to 
> be made to stop this? Similar experiences? Or does everyone 
> else's keyboards work fine in this regard? 
> 
> I've got to be able to play it in a warm if not hot room and 
> depend on it being functional to be of any use. One would 
> think that originally the keyboard would have been built to 
> be robust, but man that heat-sink looks like it was designed 
> to dissipate a lot of heat!

Under normal conditions, the heat sink gets pleasantly warm to the touch,
not hot by any stretch of the word. The only thing I can think of that would
make the heat sink really hot is if you were running on 240V while the
selector switch is set to 120V. But since you're in Canada (I assume from
your e-mail), that wouldn't be an issue.

If it's not getting really hot, the most likely culprit is that you've got
the early version of the power supply, with three trimmers on it, and the DC
OK threshold is set too low. The late version only has two trimmers, but has
a more reliable DC OK circuit which doesn't require adjustment. If you have
the early version, you can easily adjust this with your finger, by turning
R17 on the supply until LED CR10 turns on, and then turning it a little
further, maybe 5 degrees.

-- 

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