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Subject: Re: [chromapolaris] CP strange behaviour

From: Antonio Tuzzi <antoniotuzzi@...>
Date: 2005-02-22

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.
>
>