Adjustments
NOTE
If
the voltage measured across A3R13 in-
dicates a large current drain, suspect bad
RA
M.
Servicing personnel should weara static con-
trol wristband to avoid Electrostatic
Discharge
("Static
Zap")
of
the components
within the 3314A. Potentials as low as 500V
though
not
noticed by touching the instru-
ment, can damage sensitive components
within the instrument.
D. Simultaneously short the (+)terminal
of
A3BI to
ground while measuring the DC voltage across the bat-
tery. Maintain the short and measurement for approx-
imately five seconds. Monitor the voltmeter display and
verify that the voltage remains >2.20V.
(REMOVE
SHORT
IMMEDIATELY
AFTER
MAKING
THIS
MEASUREMENT.)
NOTE
If
tile battery
voltage
failed to remain >
2.20V;
suspect not only bad RAM, but also the pos-
sibility that A3CR2 may have been destroyed
while probing. This would result in current
loadingby thepower supplies.
A11
E. Briefly place a short across A3C29 to discharge the
capacitor. Then measure the battery voltage at A3U211
pin 24 with respect to ground. The voltage should be
~
2.5VDC
but
< 3.5VDC.
NOTE
This step is a check to insure that the short
applied in step D did
not
drain
A3B]
below
its required operating potential.
5-2
Model 3314A
5·3.
POWER
SUPPLY
ADJUSTMENT
This adjustment enables the 3314A to generate accurate
voltage levels (through Amplitude Calibration) and
calibrate its frequency over the proper range by setting
the
-15VDC
and + 15VDC supply levels and measur-
ing the
+5VDC supply.
Equipment Required:
AC/DC
Digital Voltmeter
Procedures:
A. Preset the 3314A.
B. Set the digital voltmeter as follows:
Function DC
Range Auto
Trigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Internal
Math
Off
Sample Rate Maximum
C. Using the voltmeter, measure the
-15VDC
sup-
ply with respect to ground on A115 pin 17.
D.
If
necessary, adjust A3R1l3 until
-15VDC
± 5mV is measured on the voltmeter.
E. Measure the
+15VDC supply with respect to
ground on
AlJ5
pin 20.
F.
If
necessary, adjust A3R1l4 until +15VDC
± 5mV is measured on the voltmeter.
G. Measure the +5VDC supply with respect to
ground at A3TP3. The .level should be 5.1VDC
±lOOmV.
NOTE
If
the voltage measured in step G is below
the specified level, disconnect cables A3J1
through A3J3 while continuing to monitor
the
+5V
supply at A3TP3. This will deter-
mine which
PC
assembly is causing the
failure.
If
after J1 through J3 have been
disconnected the voltage remains below the
required level, suspect problems with either
the controller hardware or power supplies.
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