> ... 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"..

Terrific! That's great news.

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

As the power supply had been worked on, it would probably also be good to
double-check the other voltages coming from the supply (to make sure they're
OK).

Assuming everything looks OK there, (and if you have not already done so), I'd
suggest that it would be good to go through the Adjustments and Checkout
section of the service manual, which will confirm such items as the DAC null -
and will also ensure that the volume leves are set up and memory is restored
(the most common reason for loosing all of the audio, especially if the error
honk is missing, would be that the memory data has been lost and has to be
recalibrated - although that should not explain why the voices will not
auto-tune.)