Rhodes Chroma Polaris

> From: Mario Faelli
> 
> May you give me the exact Z53 chip code ?
> Do you think it should be easy to find ?

http://www.digikey.com/product-detail/en/ADC0804LCN/ADC0804LCN-ND/3701254

I'm not certain it's the problem, though. The first thing you should do is
to check all the power supply voltages. It's important to check them on the
power supply board, and also on the panel boards. Sometimes problems like
this are caused by a bad connection between boards. A cable can have a
broken wire in it, or a connector can have dirty contacts. So check all the
cables, unplug them and plug them in again several times to make sure the
connector contacts are clean.

The panel boards have lots of different power supply lines, including three
separate grounds and three +5V lines. You should measure ALL the supply
voltages relative to a single ground point. If you have a meter, connect the
common (black) lead to the ground lug sticking out of the middle of the main
board, and use the other (red) to measure ALL the supply voltages on the
right panel board. These include:

	LED GND, DIG GND, ADC REF
	LED +5V, +5V DIG, ADC REF
	+12V ANA
	-12V ANA

Yes, you should check the ground circuits, to make sure they are very close
to zero volts. A bad ground connection can cause problems. Without removing
the boards, you can measure the voltages at the connector pins.

> In the input jack area I see a brown cable coming from the 
> preamplifier board ( LM384 ) that it is unconnected , do you 
> think it is this the reason that Polaris stop playing sounds ?

That board is an output board, not a preamplifier board.

There is a brown wire that comes from the cable that plugs into J13, but
doesn't connect to anything at the other end. Originally it was a ground
wire to the output jacks, but it caused a ground loop so it was
disconnected. But the cables had already been manufactured, so the wire is
still there.

-- 

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