3000 watt APC UPS won't work - no power to outlets on back even!

Thread Starter

RogueRose

Joined Oct 10, 2014
374
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?
 

eetech00

Joined Jun 8, 2013
1,738
How the APC works depends on the model. Some will pass AC to the outlets and trickle charge the batteries until AC Input power fails. Some have fuses or breakers. Some have a "bypass" mode so the batteries can be changed without interrupting the AC load. What is the model number of the UPS?
 

Thread Starter

RogueRose

Joined Oct 10, 2014
374
How the APC works depends on the model. Some will pass AC to the outlets and trickle charge the batteries until AC Input power fails. Some have fuses or breakers. Some have a "bypass" mode so the batteries can be changed without interrupting the AC load. What is the model number of the UPS?
SURTA1500XL is the one that is doing the no pass through. I'm having almost identical problems with a2 larger ones who's model are 2200XL (IDK full, main board dates are 1996 and 1995, lol, but they look brand new - gov data center stored) I can get more info on those when I get time later today.. Thanks though
 

eetech00

Joined Jun 8, 2013
1,738
What is the status of the indicator lights on the front panel?

Bypass mode is usually used to maintain AC to the outputs while replacing the battery(s).
Is the "bypass" indicator lit? If not, try placing the UPS in bypass mode.
It should then route AC internally to the outputs.
 

ian field

Joined Oct 27, 2012
6,539
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?
Some types sense battery internal resistance and shut down completely if it rises.
 
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