Very much appreciate the meter data interpretation. Yes 2 mega ohm - that was a typo. I think it may just be the meter, but in sequential measurements it rested at something as low as 0.5 M ohm or as high as 2 M ohm.

Next week I'll have a chance to pick up the external SCSI cases, replacement floppy drive, and another logic board that had been pulled from a IIsi that I'm told was retired for the sole reason of the usual speaker contact problem.

Thanks.

PS I'm fascinated by what kind of motherboard "wash" is recommended here. I see a range online from what appears to be organic solvent immersion (like dry cleaning), isopropanol (either 91% drugstore or 100% commercial) with a brush or cotton, distilled or deionized water, bathroom cleaners, dish soap and hot water (even in a dishwasher), followed by various drying methods.