Check
Check
Check the
the
the Bleed
Bleed
Bleed Resistor
Resistor
Resistor
The bleed resistor (24) is used to help discharge the
system voltage and to measure system performance.
If the displayed voltage appears to be inaccurate,
use the following procedure to check the resistance
value of the bleed resistor.
Use megohmmeter Part No. 241079 (AB) and an
applied voltage of 500 V.
1.
Prepare the isolation system for service. See
Prepare the Isolation System for Service, page
93
2.
Use a flat blade screwdriver to open the isolation
cabinet door.
3.
Slide the electrostatic shield (12) up to remove.
4.
Slide the electrostatic shield (12) to the left to
remove.
5.
Follow the wire from the top of the bleed resistor
(24) to the kV board (428) and loosen the
terminal screw to remove the wire.
6.
Attach the positive lead of the megohmeter to the
wire and touch the negative lead to the threaded
stud at the bottom end of the bleed resistor (24).
7.
Measure the resistance. The resistance should
be between 9 and 11 Gigohms.
• If the value is inside the range, then calibrate
the bleed resistor. Follow the procedure in
Calibrate the Bleed Resistor, page 62
.
• If the value is lower than 9 Gigohm or higher
than 11 Gigohm, then replace the resistor.
8.
Reattach the wire in the terminal screw.
9.
Reinstall electrostatic shields (12 and 82) inside
the cabinet.
10. Close the cabinet door and use a flat blade
screwdriver to secure the door shut.
Check
Check
Check the
the
the Door
Door
Door Switch
Switch
Switch
A door switch interlock automatically discharges the
system voltage any time the door on the isolation
cabinet (1) is open. Use this procedure to determine
whether the door switch is working properly.
1.
Navigate to Maintenance screen 5 and activate
the grounding rod (N). See
Valve Resets and Test, page 65
2.
Manually depress the door switch. If you hear
the ground rod retract and extend within a few
seconds, the door switch is working properly.
3A7370C
73
