12
7. INTERNAL MAINTENANCE
I
I
WARNING
Only qualified technicians or supervised personnel should open the UPS and only after ALL of
the following WARNINGS and instructions are read and fully understood.
Mesta's UPS has been designed to provide unprecedented reliability; therefore it requires little or no
maintenance. However, should internal maintenance be required, please adhere to the following
warnings and instructions.
I
I
WARNING
Risk of
Electric Shock
exists inside the UPS. The UPS receives power from the AC source
(via the AC power cord) and a DC source (via the internal batteries). Maintenance personnel
must be aware of this hazard or they may be exposed to an electrical shock hazard that could
result in death or injury or damage to the UPS or its electrical loads.
I
I
WARNING
The UPS internally contains capacitive components which remain energized even after power
to the UPS has been turned off. A unit's front panel LEDs are functioning normally such that
when the unit is turned on, one or more of the LEDs lights up steadily or periodically, and when
the unit is then turned off, all LEDs go off within 20 seconds. Under these circumstances the
voltage across these capacitive components will be minimized to safe levels within 1 minute of
turning the UPS off. If, however, the LEDs never come on or never go off during operation of
the "ON" and "OFF" switches, a problem exists with the unit. Under such conditions it is
possible for hazardous voltages to remain for longer periods of time. If such a malfunction
exists, it is advisable not to open the unit. Instead, contact the manufacturer or nearest repair
center.
Instructions for Opening and Closing the UPS:
Before opening the unit, make sure the UPS power
switch is "OFF" and the AC power cord is unplugged. Make sure all front panel LEDs go off. Next,
remove the battery fuse, located at the upper left side of the back of the unit, by turning the fuse cap
counterclockwise. Then pull out fuse/fuse cap, being careful to touch only the plastic cap while
extracting the fuse. To avoid risk of
Electric Shock
, DO NOT
probe into empty fuse holder.
Four #6-32 screws must be removed from the bottom of the unit so the UPS cover can be removed.
To access these screws, either lay the unit on its side or position the end of the UPS slightly over the
edge of a work bench so you can reach two of the screws at a time from below. Once the four screws
are removed, set the unit upright and slide the cover towards the rear of the unit.
DO NOT
try to enter the unit any other way (such as removing screws from back of unit) as such an
action may result in risk of
Electric Shock.
If extensive work is to be done within the UPS, remove
the batteries from the unit as described in the
"Battery Information"
section of this manual. When
servicing inside of unit is complete, return the cabinet cover to its original place on the UPS and
replace the four #6-32 screws in the bottom of the chassis. After making sure power switch is still in
the "OFF" position, place fuse cap on one end of the fuse (if the two have become separated) and
screw fuse/fuse cap clockwise into empty fuse holder, being careful to touch only the plastic part of
the cap.