Johnson Controls Frick QUANTUM Series Maintenance Manual page 18

090.560-M (APRIL 13)
Page 18
DESCRIPTION
The power supply of the Q5 control panel consists a sin-
gle, 12 volt DC supply, and is located on the DIN rail at the
back of the enclosure.
The supply is adjustable and has an indicator to show that
it is powered. Refer to the following page for the location
for the adjustment.
Power ON
Indicator
12 Volt DC Power Supply
POWER DISTRIBUTION
12 Volt DC Power is distributed to the Q5 processor board
and Interface Board.
MEASURING VOLTAGES
CAUTION! Measuring and adjusting the power supply
voltage requires the control power switch to be ener-
gized. Extreme care must be observed when taking any
readings, as 120 or 230 VAC (depending on incoming sys-
tem voltage) will be present next to the DC voltage con-
nector. Adjusting the supply requires the use of a small
Philips screwdriver inserted into the supply to access an
QUANTUM™ LX CONDENSER/VESSEL CONTROL PANEL
MAINTENANCE
Q5 POWER SUPPLY
adjusting potentiometer. CAUTION: It is possible for the
screwdriver (and the person making the adjustment)
to come into contact with potentially lethal voltages.
Proper Personal Protective Equipment (PPE) measures
need to be observed.
All circuit boards within the Q5 control panel require ac-
curately adjusted DC voltages in order to function prop-
erly. Periodic measurement and adjustment of the DC
power system is recommended for optimum system op-
eration. Over time, it is possible for temperature, humid-
ity, vibration and component age, to degrade the accuracy
of these voltages. When any of the DC voltages begin to
stray from their optimum range, mysterious problems can
begin to arise.
Even with a perfectly adjusted supply, it is possible for a
potential drop in voltage at each connection point. This
drop normally is in the millivolt range, but under some
conditions, the drop can be much greater (as high as
tenths of a volt). Some examples of problems could be:
• Loss of or intermittent communications failures.
• Q5 reboots for no apparent reason.
• LED's on the Q5 are lit, but nothing appears on
the display.
To perform measurements and adjustments on the power
supply voltage, use a reliable, calibrated Digital Volt Meter
(DVM). The DVM should be accurate to 1/100 of a volt DC.
With the control power switch turned ON, wait until the
Operating Screen appears. This is because the graphics
required to create this screen will draw more current than
when the screen is showing the normal POST (DOS) style
messages during a boot up. If the screen never appears
however (possibly due to a voltage problem), you will
need to proceed regardless of what is or is not displayed.
In order to properly measure the DC power system, it
must be checked at the DC power supply.