Hi Albert. Appreciate the advice. I have checked the XY mode, but only with
no signal. The dot near the middle does move slightly, but only about a
half-an-inch or so. I don't have any way locally to create a triangular
wave form, and I don't have, or know anyone, with a second scope to use for
testing. I hope I don't need to desolder any of the transistors to check
them out. That would require some extensive disassembly, as far as I can
tell from looking at the physical component locations.
