Rhodes Chroma Polaris

Hello polarized friends, Hi David,

Ok I changed all the caps and no result,

at the end I changed the lm305k (the incoming voltage was correct) and 
bingo!

now the DIG voltage is stable a +5.00 and the DIG OK signal is "OK"..

The polaris starts

but!!

AAAHAHAHAHAHAHHAHA

is saying all the voice are defective ?
If I turn on all the channels no audio is coming out!

Let's clarify, that I worked on the voltages correction detaching the 
jp4 and jp3 connectors!

the tune all function is blinking just one time, and after all the 
voices are shut down.

I have an xpander, and I tested (just one) cem and is working!

so must be something else.

Another strange behaviour: the click for the metronome is missing, and 
so the click for pressing button and "honk" for the error:
I dont think the sound effects are generated using the 3374 (???)

Any idea help help help

Ciao
Antonio Tuzzi


On Giovedì, feb 17, 2005, at 02:57 Europe/Rome, David Clarke wrote:

> > ... At startup, sometimes about 90 % of all leds are on,
> > but is not  possible to change any parameter. Sometimes,
> > after a couple of secs goes ok.
> ...
> > I'm suspecting that the DC OK signal sometimes is not up
> ...
> > I'm getting
> > a maximum DIGITAL DC +4.2 (maximazing the trimmer, 4.01 at minimum
> > position). I have the second type board (so no trimmer for the DIG OK
> > signal)
>
> If this is actually the output of the 5V digital line that you're 
> reporting,
> then that would seem to be the source of the problem (i.e., 4.2v is .6 
> or .7
> volts too low for good operation - and per the docs, you should be up 
> at 5.0v).
>
> The solid-on LED indication would indeed likely be due to the DC OK 
> signal
> never getting up there (since the power supply is struggling to get to 
> a point
> where the 5V is "ok."
>
> If the voltage is really that low too - then other system operation 
> would also
> be questionable.
>
> > Do you think is the LM350k or is the power coming in that is too low 
> ?
> > and what would be the correct incoming voltage from the transformer?
> > Can be the low voltage caused by old lytics caps ?
>
> I wouldn't immediately expect the electrolytics, but I would certainly 
> look at
> the input voltage to the LM350 to see what sort of levels you are 
> seeing.  If
> you can, it would probably be good to look at this with a 'scope.
>
> While the circuitry between the old and new PSUs are different, I 
> would still
> expect to see the same order of magnitude of voltage going into the 
> voltage
> regulator - so that'd be about 13V coming in, with a ripple frequency 
> of 120Hz.
>
>