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z
Finally, the display will
show
the following message dur-
8.8.4
Power
supply
Checks
ing the signal phase:
P=S
All power supply voltages should be checked fit
to make
sure they are within the required limits. If the various oper-
atine voltaees are not~within the readied limits, trouble-
8. To remove the instrument from the diagnostic mode, turn
sho&ng &e re maining circuitry can be quite difficult.
off the power.
During normal operation, the instrument cycles through
these three phases in rapid succession. This cycling a$on
makes it difficult to troubleshoot the instmment~ utilizing
normal signal-tracing techniques. However, by using the
diagnostic program to "freeze" the instrument on the ap-
propriate phase, troubleshooting is greatly simplified. Table
8-7 summarizes phases, display messages, and signals ap-
plied to the A/D converter during each of the three phases.
Table 8-8 outlines the various power supply voltages that
should be checked. In addition to the usual voltage checks,
it is a good idea to check the various supplies with an
dscilloscope to make sure that no noise or ringing is
present.
8.8.5
ND Converter Checks
Table 8-7. Diagnostic Program Phases
Use the orocedure listed in Table 8-9 to make sure the AID
converter is operating properly. The operation of the AID
converter should be verified before attempting to trouble-
shoot the analog circuitry.
A/D Converter
Display
Input Signal
8.8.6 Voltage Source Checks
Phase
Message
(ulZ9, pin W)
Check out the operation of the voltage source by using the
Zero (Common)
P = 0
Analog Common
procedure in Table 810. The first 10 steps in the table check
Calibration
P=C
-2V Reference
the voltage source circuiq, while the remaining steps check
(Reference)
out the step~voltage circuitry. Note that the power supply
voltage should be checked fir&to ensure proper operation
Signal
P=S
O~utput of Preamplifier
of the voltage source.
(Xl) or X10 amplifier
Table 8-8. Power Supply Checks
step1 Item/Component Required Condition
Remarks
Set to 115 or 230 .a~ required
Lie
voltage selection
Check for continuity
Remove fuse and measure
resistance (-2523 for FU-20,
453
for FLJ-21).
:
Line Power
Connect line now3 & hnn on
.--.-.-'-~~~~
~~~~~~
&XV supplies
+27.i
_~ ~3 *X30/
Referenced to f24V common
5
+W
_ - V supplies
+l5v, -uv,
*lO%
Referenced to analog common
6
+9D supply
+9V +16%
Reference to digital common
I
7
+SD supply
+5v *5%
Referenced to digital common
1
s-19
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Table of Contents
Troubleshooting
