HP 4262A User Manual

START —™
NO
Is the trouble solely with |
Set 4262A controls as follows:
ZERO ADJ C control
function?
YES
Set 4262A controls as follows:
FUNCTION........... R/ESR
CIRCUIT MODE .
Unknown....... .. Open(OpF)
Is signal voltage at A12U1 pin 1
within 2.8Vp-p * 0.15V?
YES
Does signal voltage at XA12
pin 3L change between OV
and 2.8Vp-p when ZERO
ADJ C control is rotated
{ccw and cw)?
YES NO
Check Check ZERO
ADJ C poten-
A12U1 tiometer R5.
FUNCTION...........
TEST SIGNAL. . ... veee
SELFTEST...............
Unknown...........
When FAIL is indicated on LCR dis-
play, manually control the range and
make the self test on every range.
How does the FAIL annunciation
appear?
@ On every range?
On a particular range other than
10kQ range?
©
On every range other than
10k range?
On 10k range only?
9 I@@ YES
YES
Set SELF TEST to off. Manually control range.
Is the following table satisfied?
YES
Check components shown in the table below.
Q21 Q17
Collector | Collector
Q22
Range Collector
Q18
Collector
1000mQ} 3V
10 § -11v 3V
1000 -11v 3V
100092 -11v
3V
10kQ
-11v
NO
Check the transistor which
does not exhibit correct
voltage.
Defective
Range Components
1000me | A12Q3, Q4, CR4 and CR5.
100 A12Q5, Q6, CR6 and CR7.
100Q A12Q7, Q8, CR8 and CR9.
100002 A12Q9, Q10, CR10 and CR11.
Note
If excessive dc bias voltage or a
charged capacitor connected to UN-
KNOWN terminals are possible causes
of the trouble, first check the pro-
tective circuit diodes CR4 through
CR7. Refer to paragraph 8-46,
Repair for proper method of access
to the protective circuit.
Observe waveform at junc-
tion between A12R36 and YES
RA41. Is the signal voltage
within 1.5Vpp = 0.5V
(1000m$?2
range)?
NO
vES| Isdclevelat junction be-
tween A12R36 and R41
within OV % 0.01V?
NO
Is polarity of dc at A12U2
pin 6 reverse that at junc- | YES
Check A12CR13.
tion between A12R36 and
R41?
NO
- Check A12U2 and R1.
Check A12Q15, Q186,
CR14 and CR18.
SELF TEST . ..
CIRCUIT MODE . . SER
LCR
RANGE W
Set 4262A as follows:
@ ves
Does dc level at A12Q23 Are the following dc voltages Does dc level at A12Q12
@YE§ Collector change as shown |YES | satisfied? € ® [ YES I (Q13) Collector ch < as |YES
below? following?
Range, a Q2 Q11
Range dc level %l Gate | Gate | Gate Range de level
10009 -11vV 10000]-10.6V|-10.6V|-10.6V 10002 0.6V
10k 3V 10ke| OV | OV ov 10kQ 12V
NO
NO
NO
Check the following Check A12Q12, Q13
components. €ec s >
Check A12Q23. K1 and CR3.
Incollect level Check o
Q1 Gate CR1
Q2 Gate CR2
Q11 Gate CR12
Figure 8-33. A12 Range Resistor Board Troubleshooting Tree.
Check A12Q1, Q2, Q11
and K1.

HP 4262A Specifications

General

Brand	HP
Model	4262A
Category	Measuring Instruments
Language	English