Hi Don,
I am actually away from the lab at the moment so can¹t give you an
absolutely definitive answer, but shouldn't a CPU clock be a square wave, or
there abouts? It certainly should be stable, even from a cold switch on. If
not then the patch banks and presets would go crackers until the P6 had
warmed up. It is perfectly possible to transplant the ceramic resonator from
one board to another, this I have done quite successfully in the past (it
only has two pins). However, do NOT make the same mistake as I did once and
use a 6Mhz clock crystal instead of a ceramic resonator. A crystal would
require extra circuitry. The 367 goes utterly bonkers with a crystal
fitted! Furthermore, ceramic resonators are available off the shelf¹ from
most of the major component suppliers.
Hope this helps,
Andy
BTW. Let us know what you find. Your postings always make for good reading.
On 21/05/2010 17:16, "longenough2002" <backshall1@bellsouth.net> wrote:
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> Well, the reset seems to be okay. That 6 MHz crystal on the other hand does
> not seem to be behaving well. I can't actually get a good picture of it on the
> oscilloscope. My probe has some obvious adverse effects on the signal, but is
> seems obvious that the frequency is increasing significantly as well as the
> amplitude over the first few minutes when the synth is on. The CPU is in big
> trouble until it gets a steady clock from the crystal. Should this be a sine
> wave? It looks like a sine now that it's warmed up. It was very spiky when
> cold. Not sure it any of this can be blamed on either of those two little
> capacitors. How safe is it to unsolder and resolder a crystal from another
> KLM-367?
> Don B.
>
> --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , Andrew
> Jury <andy@...> wrote:
>> >
>> > Hi Don,
>> >
>> > Best thing to do measure pin 4 on the CPU at switch on.
>> > The output from the comparator should drop active low for
>> > about a second and then swing back to five volts. I had
>> > a very similar problem a while back which looked like this.
>> > One end was coming off the ceramic resonator! So do check the
>> > REST pulse and draw you conclusions.
>> >
>> > Cheers,
>> > Andy
>> >
>> >
>> >
>> >
>> > On 18 May 2010, at 14:14, "longenough2002" <backshall1@...>
>> > wrote:
>> >
>>> > > I've got a Polysix here that doesn't seem to initialize properly on
>>> > > cold mornings. Symptoms range from mild to bizarre. Sometimes I turn
>>> > > it on and the lights all come on, then it switches to just A,1,Poly
>>> > > like it should, but doesn't seem to have loaded all of patch A1
>>> > > parameters properly. Hit the "1" button again and it's fine. Other
>>> > > times, none of the lights go off and hardly any knobs respond. If I
>>> > > leave it on for a few minutes, then turn it off and back on, it
>>> > > fires up properly. The Reset adjustment procedure was done after it
>>> > > was warmed up, as per instructions. Could it need tweaking for cold
>>> > > starts? How exactly does it work? With that big C21 and a zener, it
>>> > > looks like it just delays the initial reset until the 5v supply is
>>> > > up to snuff.
>>> > > Don B.
>>> > >
>>> > >
>> >
>> >
>> > [Non-text portions of this message have been removed]
>> >
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