HP 4262A - Page 231

START ——»
Set 4262A controls as follows:
Manually set CIRCUIT
MODE to SER and LCR YES
TEST SIGNAL .
TRIGGER
Unknown
Monitor signal at A13TP1. Does it look
like this?
A13TP1
2.740.15Vpp
Is waveform at A13U1 pin6
as illustrated?
A13U1 pin 6
2.710.15Vpp
RANGE to 1000m{2 range.
Short-circuit UNKNOWN
terminals together (002).
Monitor signal at A13TP2.
Does it look like this?
Al13TP2
1.2 0.15Vp-p
Is waveform at A13U2 piné
as illustrated?
A13U2pin 6
1.2+ 0.15Vpp
NO
Monitor signals at A13TP2
and TP4. Do they look like
this (adjust positions of the
waveforms on oscilloscope
YES
Is waveform at A13U5 pin
3 the same as that at TP2?
satisfied?
Set 4262A controls as follows:
Monitor signal level at A13U5
pin 1. Is the following table
YES
LOW LEVEL
Level at U5 pin 1
off 2.7V £ 0.14Vpp
on 2.7V + 0.14Vpp
NO
00]
YES
NO
Check A13U4
Check A13U2. and R2.
Check A13U1,
CR1 and CR2.
Check A13U3*
and R1.
* Check dc level at A13U3 pin 2. If the
de voltage exceeds +5mV,check A11U2.
Note
I U-CL annunciation is always dis-
played on LCR DISPLAY, check
first A13U8. If OK, disconnect one
side of A13R79 from A13 board.
Set LCR RANGE to 1002
range. Is waveform at
A13U5 pin 7 as illustrated?
Do the check whose item number(s) corresponds with
the number alongside flow diagram arrow.
1. Take out A22 board.
Set switch A22 S1 to
position TST 1. Install
A22 board in its normal
position.
3]
- Observe signal at A13TP3.
Trigger osciiloscope ex-
ternally with signal from
AZ21TP3. Is the wave-
form as illustrated?
A13TP3
Push LOW LEVEL button
twice (on and off). Is the
observed difference in am-
plitude within +0.2Vp.p?
YES
NO
Check A13Q17 and CR4.
YES
Is waveform at A13Q15
Collector as illustrated?
A13Q15
NO
Is waveform at A13U6 pin 3
as illustrated?
A13U6 pin 3
Collector
Check A13Q18, Q19,
A13U5 pin 7
10.2+ 0.1Vp-p
YES
Check A13U7 Check A13U5,
and CR17. CR15 and CR16.
4262A trol
settfzg © Check point | Voltage Level
LOW LEVEL: off -12v
| Low LEVEL, on | Q18 Collector 3V
@] ser I 3V
@ PRL Q7 Collector 12V
@ Q9 and Q12 { Changes between
Collectors 3V and -12V
YES NO
Check A13Q16 and CR3. Check A13Q13.
Check A13Q4 and CR9.
Check A13Q7 and Q8.
Check A13Q1 and CR4.
Check A13Q7 and Q8.
©
OB
Check
A13Q2,
Q3,
Q5,
Q6
and
associated
diodes.
Check A13Q9, Q10 or Q11,
Ql2.
Check A13U6.
Figure
8-36.
A13
Process
Amplifier
Board
Troubleshooting
Tree.
CR18 and CR19. If correct,
check A13Q2, Q3, Q5, Q6
and associated diodes.
NO
Check A13Q14 and Q15.