congratulations on your perseverance John. This is hardly the first time that someone has resolved an issue without really understanding exactly what happened & why. I was thinking though, if you have further problems with the DVD player you could (1)replace it or (2)have it serviced (for possible degraded capacitor in the power supply) or (3)try an AC line isolation transformer, for power to that offending component only.
I had some screwball/intermittent noise problems with my computer, which I unsuccessfully tried everything that I could think of to fix. I ended up buying a small-ish (3 amp) isolation transformer on EBay for about $25. It was originally designed for homeuse medical equipment. What this does is float the power supply such that neither side of the AC line connects to household grounded neutral. Easy fix, but I don't know what / why either.
I had some screwball/intermittent noise problems with my computer, which I unsuccessfully tried everything that I could think of to fix. I ended up buying a small-ish (3 amp) isolation transformer on EBay for about $25. It was originally designed for homeuse medical equipment. What this does is float the power supply such that neither side of the AC line connects to household grounded neutral. Easy fix, but I don't know what / why either.

