Wang 5536 - Chapter 7 Troubleshooting Procedures; General Troubleshooting; PCA 7544;7744 Problems; PCA 7545 Problems

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CHAPTER 8
TROUBLESHOOTING PROCEDURES
8.1 GENERAL TROUBLESHOOTING
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Effective troubleshooting is carried out from a system viewpoint. No
procedure can list every potential problem or combination of problems for
even a very simple device. The troubleshooting flowcharts provided in
this section are intended as aids for systematic investigation, diagnosis,
and repair of failures conunon to all 5536 workstations described in this
manual.
8.2 PCA 7544/7744 PROBLEMS
Problems that indicate PCA 7744/7544 difficulty are generally related to
workstation main memory or to conununication with the system master (data
link).
o Continuous READ - screen blank
o No startup - screen blank
o LINE ERROR message on startup
o PARITY message on startup -- screen slowly blanks
o All "9
11
s displayed on screen -- PROM trying to load. Correct switch
setting. Switch 1 must be OFF.
8.3 PCA 7545 PROBLEMS
Problems that indicate a bad 7545 PCA are generally related to CPU, video,
or keyboard functions. The board should be swapped when any of the
problems listed here are encountered.
o Keyboard repeat keys function incorrectly
o Keyboard entry is erratic or absent
o Display is erratic or erroneous
o Video sync. problems (try pot adjustments first)
o Intensity and character control (underline, etc) problems (try pot
adjustments first)
o Beeper/clicker problems (also check speaker and speaker circuit)
o Faulty peripheral selection
o System program does not load
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