> From: sonicalliance@...
>
> I am having an issue with the synth and I needed some help.
> When I turn it on, all of the LEDs on the front panel are
> lit. No sound when I press keys, buttons do not respond. I
> tried turning it off, waiting and turning it back on. This
> worked twice over various on/off attempts. When I was getting
> sound out of it, all sliders worked. I was able to change
> patches and modify some parameters. Some membrane buttons
> didn't work, but most did.
>
> My question, is the membrane related to the boot issue? Will
> a new membrane install solve it? Or is that a separate issue?
> I have been searching through the manuals for some type of
> reset function to see if that will fix the problem. I learned
> about the Warm Reset and Reset functions, but I can't seem to
> use them while the synth is in the error state.

When the system doesn't respond at all, it means the computer isn't running at all, or has crashed. There are two common causes of this in old Polarises:

1) You have the old version of the power supply, which holds the processor in the reset state until the voltage is above an adjustable threshold, and that adjustment has gone out of whack after a long time. This power supply has a red LED that turns on when the reset signal goes off, so it's easy to see if this is causing the problem, and trivial to fix: you just twist the nearby trimmer (R17) to find the point where the LED turns on or off, and go past that by about 10 or 20 degrees so that it is safely on.

2) The EPROMs holding the software have faded, and occasionally a bit is read incorrectly, crashing the computer. It's hard to know when this is a problem, but you could tweak the +5V supply both upward and downward with power supply trimmer R9 (old board) or R4 (new board without LED) to see if it changes anything. (On the old board, you'd have to readjust R17 to make sure the LED still comes on.) It's best to do this while monitoring the voltage with a meter, to stay within 4.5V to 5.5V. This may not reveal anything, but if some bits are on the "hairy edge", they may be sensitive to supply voltage.

If this is indeed the problem, the solution is simply to erase and reprogram the EPROMs, and then go through the whole initialization and calibration process described in the service manual. The code and all manuals are available on the rhodeschroma.com site (use the latest version). If you don't have a programmer, and can't find anyone who can do it for you, you could buy an eraser and programmer on eBay and do it yourself. For about $50, you can get a Willem programmer on a circuit board without a box, and an eraser, or get a GQ programmer in a nice package for about $100.

Of course, beyond that, there are any number of other things that could cause the problem, which would be more difficult to diagnose, except by someone with some real electronic experience and a decent scope, but those two are the first things to look at.

--

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