Thanks for the tip about the charger voltage; you're right, it shows faintly embossed just next to the plug; 5 volts.

My equipment is;
Marantz SR750 amplifier
Sharp LC 37HV4U tv
Bell Expressvu 5900 and 6000 Satellite receivers (I don't know who actually makes them, and by the way I've had no luck trying to get or learn their IR codes)
LG LRA 536 DVD player/recorder
Sony SLV N80 VCR

The MX3000 has now worked several times; I haven't used the euipment much in the last day. I don't know how long it will last and I sure don't know why it didn't charge up on one plug and does (so far) on another with the same voltage. It might be that the first plug was after two surge protectors in series (because of how I've had to hook up all the equipment). But the final voltage is the same in both cases: 125 volts.

Thanks all for your interest and help.

Roman