Thanks everyone, and especially Radu for the info on TCC!? Definitely a resource for me to bookmark.
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I did substitute the resistor using a 15K and 820 ohm resistor in series from my parts bin, sorting through the population to make up something as close to the original 15.82K as possible, at least at room temp.? The resistors I have on hand are just run of the mill 1/4W 5% carbon film, so really poor tempco.
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Once installed everything works as expected, other than not being exactly the correct voltage as the substitution wasn't spot on.? Still it proved me to that there's nothing else wrong going on.
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For now it's buttoned back up while I search out if I can find an exact'ish part at a good price, or decide I can live with a cheaper substitute.?
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Dave
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