2465B/2467B Service
REGULATOR TROUBLESHOOTING PROCEDURE
Regulator Repair Notes
Hints for troubleshooting a faulty supply Regulator:
1.
First verify that the +10-V
REF
level is correctly
adjusted;
if it is not, do so (see Adjustment Pro-
cedure in Section 5).
2.
Regulator output is
high:
Is the output loaded? All Regulators
(except +10-V
REF
) require some load to
regulate, the lower voltage supplies requir-
ing greater loads. The Regulators between
+
15
V and -15 V may be loaded using
100-fl resistors of the proper
power ratings.
b. Check for
pass device.
a short-circuited series-
Check feedback through to voltage-sense
comparator.
3. Regulator output is low:
a. Check for excessive loading using the
Load Isolation diagram below and the
Interconnection Schematic (diagram 13).
b. The operation of the supply Regulators is
interdependent. If a supply is out of regula-
tion,
verify that the supply of next greater
magnitude is operating properly. Repair
faulty Regulators in the following order:
+87 V, +42 V, +15 V, +5V, -15 V,
-8 V, and then -5 V.
c. Verify that the current-limit circuit is
not activated.
d.
Check drive to series-pass device and ver-
ify that the device is not open circuited.
e. Check feedback through the voltage-sense
comparator.
If supply goes low only when fully loaded,
suspect an open-circuit diode in the associ-
ated rectifier circuit.
AC LINE
SUPPLY
RECTIFIERS
AND
FILTERS
INVERTER
BOARD
â–º
OPTIONS
(PRESENT )
i i
REGULATOR
BOARD
|
PROBE
POWER
HIGH
VOLTAGE
BOARD
i
i
"
MAIN
BOARD
CONTROL
BOARD
|
FRONT
PANEL
BOARD
*"
CRT
READOUT
BOARD
DYNAMIC
CENTERING
(2465A ONLY)
HOLDOFF
BOARD
(2467 ONLY)
SCALE
ILLUMINATION
BOARD
REGULATOR
TROUBLESHOOTING
PROCEDURE*
11
NOTE ADJUSTMENT
OR
REPAIR
OF
ANY
POWER SUPPLY REGULATOR
NECESSITATES
A
COMPLETE
RECALIBRATION
OF THE
INSTRUMENT.
READ
THE
NOTES
ON REGULATOR
REPAIR
AT
LEFT
USING
A DMM,
CHECK
THE +10V
REF VOLTAGE
NATURE
OF
ERROR?
0V
OUT
OF
LIMITS
NATURE
OF
ERROR?
0V
OUT
OF
LIMITS
USING
THE
REGULATOR
REPAIR NOTES
AT
LEFT
AND
THE
THEORY
OF
OPERATION, CHECK
AND
REPAIR
THE
REGULATORS
IN
THE
FOLLOWING ORDER:
-15V UNREG (FUSE 1330) ,
+87V, +42V,
+
15V,
+5V,
-15V, -8V,
AND -5V
CHECK +5Vp FEEDBACK
PATH THROUGH V1371C
AND U1040. EXERCISE
THE CIRCUIT
BY
VARYING R1292*
(VOLT
REF
ADJ)
AND
VERIFY THAT +5V
D
VARIES
CHECK FUSE F1102,
RECTIFIER CR1110,
C1110,
C1111
,
L1110,
AND +5V
OUTPUT WINDINGS
OF TI060
YES
YES
REPAIR PATH
THROUGH U1371C
AND U1040
REFER
TO THE
INVERTER
PROCEDURE
YES
SET
+10V REF FOR
PRECISELY
+
10V*
YES
CHECK
FOR
EXCESSIVE
LOADING
OF +10V REF.
FIRST CHECK VR1293, THEN
REMAINING LOAOS.
USE THE
LOAO ISOLATION DRAWING
AT LEFT
ANO THE
POWER
DISTRIBUTION DIAGRAMS
SET SWITCH
(S90)
TO MATCH
THE
LINE VOLTAGE
PROBLEM
IS
WITH
+15V UNREG
AND
-5V UNREG SUPPLIES
CHECK APPROPRIATE
RECTIFIER, FILTER
COMPONENTS,
ANO
TRANSFORMER WINOINGS
CHECK C1400,
U1290,
U1300C
AND ASSOCIATED
CIRCUIT COMPONENTS
CHECK ASSOCIATED
RECTIFIER, FILTER
COMPONENTS
,
AND
TRANSFORMER WINDINGS
TROUBLESHOOT
OVERLOADED
BRANCH
REPAIR
INDICATED
FAULT*
3
m
OO
OC
m
r
="2
H
3
O
C
CO
o
O
H
6019-38A
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