6-44
3. If no voltages are present, troubleshoot the HV power supply. The -15 V Unreg supply is fused
by F961 (schematic diagram 23) which will be open if a component failure in the HV power supply
caused excessive loading.
A High Voltage probe is required to measure the grid, cathode, and anode voltage of
the crt.
I
WARNING
I
2. If no display is present, check the crt intensity grid voltage (V1000 pin 3), the grid bias adjust, the
crt cathode and heater circuits, and the crt anode HV.
1. Press STATUS to set READOUT level.
If there is no GPIB capability, troubleshooting is going to be more difficult if no display is available. The
steps in this table address the analog problems not detectable by the Extended Diagnostics in any
case. Digital failures of the Display System are covered in the troubleshooting tables in the "Diagrams"
section at the back of this manual.
No Intensity (HV Supply and CRT, schematic diagram 19):
INTENSITY
6 DISPLAY TROUBLESHOOTING
2. If GPIB interface is not available, go to Procedure 6 to troubleshoot the display problem.
1. If the hardware and software are available to interface a 2430 to a GPIB controller, then run the
Extended Diagnostics test. Troubleshoot any failed diagnostics test as indicated in Procedure 7.
Extended Diagnostics test may be run via the GPIB interface to track down failed devices when the
Front Panel is locked up due to a front-panel failure or when there is no display visible. The importance
of this is that the initial step of locating all problem areas is simplified when the 2430 can do it itself.
GPIB CAPABILITY AVAILABLE FOR EXTENDED DIAGNOSTICS
5
If A120402 is + 0.3 V, and the relay is open, replace K302.
Check 0402 collector for +0.3 V. If not correct, then either the transistor is defective, the drive to
it is incorrect, or the relay coil K302 is open.
PIN WON'T CLOSE:
If A120402 is +5 V, and the relay is closed, replace K302.
Check 0402 collector for + 5 V. If not correct, then either the transistor is defective, the drive to it
is incorrect, or the relay coil K302 is open.
PIN WON'T OPEN:
Pen Lift Circuitry (schematic diagram 20):
PEN LIFT
PROBLEM
4. Check that the signals on pins 4 and 15 are at -2 V when not plotting. If not ok, replace
A12U130.
Table 6-6 (cont)
Maintenance-2430 Service
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