I wouldn't have thought so Paul. Here's what happened when I started swapping vcf/vca chips to try to even the levels out just for the fun of it...

>

Well.... this is bizarre. I recall someone saying prophet 600 filter/vca chips could be very picky too...(maybe that's the issue I have with a P600 here that has to warm up a bit to tune?) But didn't recall the Polaris was picky. So I noticed there was some level discrepancy in the auto tune. yet waveforms coming in to the CEM3372 looked fairly identical. Most are near the same but ch4 is actually lower by 5% maybe and 5 the one that won't tune higher by about the same.

I swap the chips. Four AND Five fail now consistently! (And yes the levels have swapped. Now 4 is high and 5 is low so it is being caused by vca discrepancies apparently) . Now I swap in a pair of chips from a scrap polaris with the same lot number. ch4 is back up..still no channel 5. And I look on the scope and I see that 4 is actually right in there now but 5 is back up high again.

So I finally swap 4 and 5 again and this time they all work! Wow. So I guess there are some fairly fine tolerences there for whatever reason. I thought we're like..just dealing with a comparator in the tune buffer that chops the signals like usual and gives a nice square wave that can be counted. Anybody got an explanation?

-------continuing

So that's the story on this end. Paul I am the king of bizarre problems. lol. It makes absolutely no sense to me.

--- In chromapolaris@yahoogroups.com, "Paul D. DeRocco" <pderocco@...> wrote:
>
> > From: Robert Weigel
> >
> > Paul, the reason 5 isn't tuning is still a mystery. I
> > swapped all the chips. No result. However the reading I was
> > getting... that was on the wrong resistor. They changed the
> > pattern I see. The envelope is showing up if I get it on the
> > right resistor :-). It looked like a clear pattern but for
> > some reason on 5 they changed it! I couldn't see the
> > writing... anyway I figured probably the hard wired leg 4053
> > chip but no dice. Still doesn't tune until I turn it
> > on..then..I find out ..it's tuned. Whaaaaatever. I dunno.
> > I need to see the code i guess to know what routine it goes
> > through on the tuning. lol
>
> The order in which things are tuned is channel 1 through channel 6. Within
> each channel, it tunes pitch 1, pitch 2, width 1, width 2 and cutoff. The
> Tune switch LED is on while tuning the pitches. You can usually tell where
> the process failed by forcibly enabling that channel and disabling the
> others, and then seeing whether the oscillators are in tune, and whether the
> pulse width goes from 0% to 99% with a proper square wave at 50%.
>
> > PS I checked the tune buffer in also and it looks about the
> > same on all channels. Actually 5's signal looks just a hair
> > hotter for some reason. 5% maybe. 4's is weakest I think
> > and it works fine. Maybe I should..attenuate it some? Too
> > weird. 5's light is always off after I tune when I do lower
> > function E....
>
> Don't bother. There's nothing wrong with the signal being a little hotter.
>
> --
>
> Ciao, Paul D. DeRocco
> Paul mailto:pderocco@...
>