Rhodes Chroma Polaris

hi all,
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?
cheers
-Sam

PS: uploaded photos of the leds that are always on in case that is relevant.

> 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@...

That's the same thing that happened to me.  Most of the LEDs lit up, nothing was responsive and no sound out of the board.  Found out the power supply voltage had drifted too far out of spec.  I had a friend adjust the voltage and it works great now.  I will need to replace those capacitors on the power supply though.  Thankfully it wasn't as bad as I thought.