Gasboy CFN Series Diagnostic Manual - Manual (Page 48)

GASBOY CFN Series
2-22 0021
DC Power Measurements and Adjustment
+5 VDC Measurement
1. Remove the four Phillips screws from the sides of the unit and remove the cover.
2. On the CPU 512K PCB, measure at the Vcc and Gnd test points. On the Memory Plus CPU
PCB, locate the 64-pin P9 connector. Using a DC voltmeter, place the positive probe (+) on
pin 63 or 64 and place the negative (-) probe on pin 1 or 2. Be careful not to let the probe
tips touch any other pins. The voltage should be +5.00 to +5.10 VDC. If the voltage does not
fall within this range, adjustment is necessary. Follow the steps below to adjust the supply. If
the voltage is within tolerance, skip to step 11.
+5 VDC Adjustment
3. Turn off the power to the site controller.
4. Remove the two screws that hold the power supply cover onto the supply. Remove the
cover.
5. Attach the meter probes to Pin 1 or 2 (black), or pin 63 or 64 (red) on the P9 connector on
the CPU PCB.
6. Turn the AC POWER switch back on.
CAUTION
Be careful not to touch anything but the adjustment screw. High voltage exists at
various points on the supply.
7. Using a 1/8 inch or smaller plastic, flat-blade screwdriver, adjust the power supply to +5 VDC
by turning the +5 VDC adjuster clockwise to increase voltage, counterclockwise to decrease
voltage. Turn the adjuster slightly to judge how sensitive the adjustment is.
8. Disconnect the meter probes.
9. Turn the AC POWER switch off and return the power supply cover to its normal location.
10. Turn the AC POWER switch back on.
+12 VDC Measurement
11. Locate the DC power input connector (P8) on the
CPU PCB. Measure the +12 VDC between the red
(+) and black (gnd) wires on the DC input power
connector of the CPU PCB. The voltage should be
+11.00 to +14.00 VDC.
NOTE: This voltage is not adjustable.
-12 VDC Measurement
12. On the P8 connector, measure the -12 VDC
between the white (-) and black (gnd) wires on the
DC input power connector of the CPU PCB. Voltage
should be -11.00 to -14.00 VDC.
NOTE: This voltage is not adjustable.
13. Replace the cover and screws of the unit.