> From: Sam
>
> I ordered a set of replacement membrane panels from Paul as
> my Polaris (which I bought used as-is) had no sound and also
> no response from the membrane panels which stayed lit up in
> one formation constantly.
>
> At any rate following the replacement of the panels
> meticulously following Paul's installation instructions, I
> find myself in the exact same situation: No sound, same
> unresponsive lit up membrane panel.
>
> I sent Paul a message to see his thoughts; I can confirm that
> the internal LED cr10 is on.
>
> Anyone have any ideas where to start looking for the possible
> cause of this?

Do you have any debugging tools available? A DC voltmeter is pretty
essential. A scope (even a crappy one) would be nice.

The first thing I'd do is download the schematics from here:

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

Then, check the power supply outputs. Make sure the DC voltages are within
10% of their correct values. Make sure AC OK is about 5V and DC OK is
above 3V. One possibility is that the big bypass capacitors on the supply
are dried out, leaving a huge amount of ripple on the supply outputs. The
AC OK or DC OK signals may even be toggling on and off at 120Hz, which
would make them read very low but not zero on a meter.

--

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