Honeywell Chadwick-Helmuth 8500C Maintenance Manual page 78

Chapter 5 - Maintenance And Repair
Problem
8520C power indicator is not on.
8500C/C+ screen display is scrambled.
8500C/C+ LCD does not operate in cold
temperature.
5-34 Chadwick-Helmuth A Business Unit of Honeywell International, Inc.
Table 5-8. Troubleshooting Guide
8500C/C+ Balancer/Analyzer
1. Verify that 8520C is receiving power. If
2. Check 8520C harness assembly
3. To determine whether one of the 8520C
1. Cold-start the 8500C/C+ in accordance with
2. Remove EPROM's in accordance with
3. 8500C Only: Remove SRAM U10
1. Verify that heater connection J3/P3 on
2. Check 8500C/C+ harness assembly
3. Measure resistance across P3 connector
Solution
8520C light is off, but 8500C/C+ light is on,
problem is isolated to 8520C.
(Figure 5-21) for shorted or open
connections which can be caused by loose
or pinched wires, unplugged connectors, or
worn-through insulation.
boards may be causing the problem,
perform the steps shown in the flowchart in
Figure 5-12.
Section 3.3, "8500C/C+ COLD-START
PROCEDURE.
Section 5.7.3, "EPROM Change
Procedure." Check EPROM's for bent pins,
etc. Reinstall EPROM's.
(Figure 5-15), while observing antistatic
precautions (which are discussed in Section
5.7.3, "- EPROM Change Procedure").
Check SRAM for bent pins, etc. Reinstall
SRAM.
NOTE: If backlight does not work,
skip ahead to backlight
troubleshooting procedure.
Heater/EL board (Figure 5-17, A4) is
connected and wired correctly
(Figure 5-19) Sheet 2.
(Figure 5-19) for shorted or open
connections which can be caused by loose
or pinched wires, unplugged connector, or
worn-through insulation.
which connects to Heater/EL board.
Resistance must be less than 100 Ω: if it is
not, replace graphics module (Figure 5-17,
(24)).