<p>OK. Thanks first of all to Pete, who immediately got back to my query. Ishould have posted the previous question in the forum.</p>
<p>As I was testing continuity around the TL074 I found, first, one small break in the trace. I'm sure I bullied it somehow. I had to fix that with a hardwire (piece of cut-off resistor) because the distance between drill holes was to great to bridge with solder. I found another that looked like a piece of dirt between to solder points - it was copper. I bridged those two with a blob of solder.</p>
<p>Now it works 100%.</p>
<p>Fun build. I just didn't have the blood sugar or optimism last night to keep looking. Ha.
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