HP 4262A User Manual

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Model 4262A
START
Section VIII
Figure 8-18
Note
Before beginning troubleshooting, install all
P. C. boards in the instrument. Connect
shorting straps to HIGH side terminals and
to LOW side terminals, respectively. Use
oscilloscope with 10:1 probe for observing
waveforms.
1.
[~
o
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All Board Check
Set 4262A as follows:
FUNCTION. ................ C
CIRCUIT MODE. . .
TEST SIGNAL . ... .
LCRRANGE ............
Unknown ..........
. Is waveform at Hcur terminal sinusoidal and
within 2.8Vp-p £0.14V?
. Change TEST SIGNAL to 10kHz and, next,
to 120Hz. Are the waveforms within 2.8Vp-p
+0.14V?
. Press LOW LEVEL button. Is the waveform
now within 140mVp-p + TmV?
YES
NO
Go to Service Sheet 11 for
troubleshooting A11 board.
*1 If the trouble is present on a particular
range, set LCR RANGE to the faulty
range.
A12 Board Check
1. Observe waveform at A12 (13L).
2. Set 4262A as follows:
FUNCTION................. L
CIRCUITMODE. .......... SER
TEST SIGNAL ........... 1kHz
Unknown .......... Short (OuH)
3. Press SELF TEST button.
4, Is the waveform a distortion-free sinusoid?
Does amplitude of the signal satisfy the table
YES
below?
Range Amplitude
100QuH 1.2V £0.1Vpp
1000uH 2.7V + 0.14Vp-p
10mH 2.8V +0.14Vp-p
100mH 3.1V + 0.14Vp-p
1000mH 2.8V £0.14Vp-p
NO
Go to Service Sheet 12 for
troubleshooting A12 board.
A13 Board Check
A.1l. Take out A22 board. Set switch A22S1 to YES Go to Service Sheet 14 for
TST 1 position. Install A22 board in its
normal position.
2. Observe waveforms at A13TP3 and TP4.
Trigger oscilloscope externally with signal
from A21TP3.
3. Set 4262A as follows:
FUNCTION........ccvvuvnn. [o]
CIRCUITMODE. .......... PRL
Unknown .......... Open {OpF)
4. Are the waveforms correct for both LOW
LEVEL (50mV) and normal level (1V) TEST
SIGNALS (see picture)?
B. 1. Set 4262A as follows:
FUNCTION................. L
CIRCUITMODE. .......... SER
Unknown .......... Short (0uH)
(3]
. Are waveforms at A13TP3 and A13TP4 as
illustrated (see picture)?
C. 1. Set 4262A as follows:
FUNCTION, ................ L
CIRCUITMODE. .......... PRL
Unknown .......... Short (0uH)
N
Is waveform at A13 (9R) as illustrated (see
picture)?
NO
Go to Service Sheet 13 for
troubleshooting A13 board.
Figure 8-18. Analog
troubleshooting A14 board.
Waveforms at A138 Board Test Points.
i bR
A ; 1V/div
A13TP3 50ms/div
A13TP4 2v/div
.5ms/div
1v/div
A13TP3 50ms/div
2v/div
A13TP4
.5ms/div
A13 (9R)
2V/div .2ms/div
r Section Troubleshooting Procedure to Assembly Level.
8-33

HP 4262A Specifications

General

Brand	HP
Model	4262A
Category	Measuring Instruments
Language	English