Thanks to Andy for clarifying the difference between the ceramic resonator and a crystal. If I had gone looking for a replacement, I would have purchased the wrong part for sure. I did move a resonator from another board to this one, and this board still has the problem. Sometimes it just flatlines for a few minutes after being turned on, then seems to resonate just fine. I replaced the 22pf and 10pf capacitors and now it resonates immediately but is fairly unstable. Actually, I didn't have a 22pf so I used a 20pf. So..... I ordered a bunch of tiny capacitors and now I guess it's also time to invest in a capacitance meter of some sort so I can see what I'm really sticking in there.
Don B.
--- In PolySix@yahoogroups.com, "grantpbt" <grantbt@...> wrote:
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> Both the crystal and capacitors have characteristics quite important to achieving god oscillation, especially in the old days. ;-) Make sure all the values are spot on and that the crystal is of the correct type/cut. You should be able to use the crystal from the old board using normal desoldering techniques. Hope the old crystal is functional. Also be careful of too much flux or other contaminants in osc area.
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> The scope will probably show a weak sine wave only. I don't have a Polysix, so I'm just speaking in general terms here. Where you should see a decent square wave is on the address lines (as low order as you can get without running into the data lines if they are multiplexed on this CPU).
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> GB
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