I've tried to figure out what is going on with my UPS and am getting strange results. Usually in a working unit when it is plugged in I can get power from the 6 120vac outlets on the back of the device (regardless if the unit is powered on or batteries are working - they are supposed to be "pass through) and continuity obviously works from the power cord prongs to the outlets. The way the device is set up is the 120vac in comes into the unit and the black & white go into the board (the ground attached to the case). From there it is difficult to trace. In the unit I'm working on I have no continuity from the 6 outlets to the power cord on any of the 12 terminals (ground has continuity). I've seen this before years ago before I knew much about electronics. I have checked all 4 fuses on the machine and they all seem good (can they read bad even if they pass continuity testing?)
Now I was thinking that this sounds like it night be a relay? If the unit is powered on with a button but has no AC connection, then it is going to try to draw energy from the batteries but if it sees AC in sufficient supply (V/C) then it will use that and charge batt's if needed. I would suspect a relay (or many) are used here? There are probably 4-5 relays on this board and I've never worked with them so I don't know how to check them.
Does my thought process about this sound logical or possible? Any ideas as to why no power to the rear outlets even when plugged in?
Now I was thinking that this sounds like it night be a relay? If the unit is powered on with a button but has no AC connection, then it is going to try to draw energy from the batteries but if it sees AC in sufficient supply (V/C) then it will use that and charge batt's if needed. I would suspect a relay (or many) are used here? There are probably 4-5 relays on this board and I've never worked with them so I don't know how to check them.
Does my thought process about this sound logical or possible? Any ideas as to why no power to the rear outlets even when plugged in?