A:
Milt,
1) This is the APC User Manual and Specifications site for the Back-Ups 650 (and ES 650) unit. Just Google "Manuals specifications for Back-Ups 650". Also, in case all else fails - The Number for APC CUSTOMER CARE (Also known as Schneider Electric the past 5 years or so): 800-800-4272.
2) First, I have used and placed a dozen or so of these type units over the past 10 years. I am now an IT manager/network engineer of about 44 years in this business. even after 44 years, I still only know a fraction of what I'd like to. Will give this my best shot: The user guide under STATUS INDICATORS makes reference to "...power only delivered from the BATTERY LOAD outlets..." and CHECK IF BATTERY LOW IS INDICATED (RAPIDLY FLASHING)? IF SO, REPLACE BATTERY PACK: PART # RBC17 - NOTE: IF YOU DO NOT HAVE THE BACK-UPS ES 650, DO NOT ORDER THIS UNTIL YOU CALL APC CUSTOMER CARE AND CONFIRM WITH THEM THAT THE RBC17 IS CORRECT FOR THE PLAIN VANILLA BACK-UPS 650 ALSO.
3) BOTTOM LINE, I HAVE NEVER HEARD OF LOSING POWER ON ONE SIDE OF OUTLETS. IT COULD BE THOUGH THAT APC DESIGNED IT THIS WAY THAT IF POWER RESERVE IS LOW, THE SYSTEM CUTS OF POWER TO THE SURGE PROTECTED SIDE IN ORDER TO CONSERVE POWER FOR BATTERY DELIVERY. HOW OLD IS THIS UNIT? LAST APC AT HOME LASTED ME 8 YEARS, THOUGH RUN TIME WAS FALLING OFF THOSE LAST 2 YEARS...IT MAY BE TIME TO REPLACE BATTERY, ESPECIALLY IF IT IS BEEPING ON A REGULAR BASIS.
HOPE THIS HELPS, BEST LUCK AND SORRY IF I DID NOT HELP.
02BirDog