Troubleshooting
Tro
ubleshooting information for the various circuits is summarized below. See the
component layout drawings at the end of Section 6 for test point locations.
Display board checks
If the front panel display tests indicate that there is a problem on the display board, use Table
4-1. See principles of operation for display circuit theory.
Table 4-1
Display board checks
Step Item/component Required condition Remarks
1
2
3
4
5
6
7
Front panel test
P1005, pin 5
P1005, pin 9
U902, pin 1
U902, pin 43
U902, pin 32
U902, pin 33
Verify that all segments operate.
+5V ±5%
+37V ±5%
Goes low briefly on power up
,
then goe
s high.
4MHz square wave.
Pulse train every 1ms.
Brief pulse train when fron
t
pa
ne
l
key is pressed.
Use front panel display test.
Digital +5V supply.
Display +37V supply.
Microcontroller RESET.
Controller 4MHz clock.
Control from main processor.
Key down data sent to main
p
rocessor.
Troubleshooting 4-13
2410-902-01.book Page 13 Monday, November 7, 2005 2:49 PM
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