6.3.5
High Voltage
Transformer
6.3.6
Generator
PCB
Chapter 6 - Detailed Diagnostics
continued
Replacement:
1.
Remove the line cord, the microprocessor PCB (see section 6.3.8), and the generator PCB
(see section 6.3.6).
2.
De-solder the primary and secondary connections and remove the two phillips head screws securing the
transformer to the base plate. Remove the transformer and replace it with the appropriate part listed in
Appendix C.
The high voltage transformer is bolted to the base plate underneath the generator PCB to the right of the low
voltage transformer and receives line voltage from the fusing distribution module. For a functional description
see section 2.2
The output of this transformer also terminates at J1 on the generator PCB. Proceed through the following steps to
test for the proper output voltage:
1.
Remove the power cord. Remove the plug at J1 and clip the digital voltmeter to locations 7 (blue
wire) and 8 (brown wire). Note: Location 1 is next to the filled keying location.
Warning: Take the appropriate precautions; locations 7 and 8 are high voltage (250 to 260 VAC).
2.
Supply power and turn the front panel switch on. With nominal line voltage, the open circuit
voltage between locations 7 and 8 should be between 250 and 260 volts AC.
3.
Remove the power cord and replace the J1 plug.
If power is available to the transformer and there is no output voltage, remove the line cord, refer to the wiring
diagram (Appendix B), and inspect the wiring leading to the transformer. If the wiring appears intact, replace the
transformer.
Replacement:
1.
Remove the line cord, the microprocessor PCB (See section 6.3.8), and the generator PCB
(see section 6.3.6).
2.
De-solder the primary and secondary connections and remove the four nuts/washers securing the
transformer to the base plate.
3.
Remove the transformer and replace it with the appropriate part listed in Appendix C.
The generator PCB is supported on an aluminum bracket above the high and low voltage transformers, and under
the microprocessor PCB. The generator PCB serves as a central point of connectivity and receives inputs from all
other PCBs and transformers. For a functional description see section 2.2.
The simplest way to determine if the generator PCB is working is by substitution. However, the following tests can
be performed if preferred.
In order to access the generator PCB's test points, the microprocessor PCB must be re-oriented in the service
position. With the line cord removed, remove the four screws securing the microprocessor PCB and use two of the
screws to re-attach the board in the inverted position as shown in figure 4.
The following steps will test the four major functional areas of the generator PCB. During these tests, refer to the
generator PCB schematic, found in Appendix B, for a more in depth understanding.
21
6.3.4
Low Voltage
Transformer
continued
