Agilent Technologies 5517B Operation And Service Manual page 95

Pin U1
1 41A5
2 0000
3 8816
4 F9C3
5 UA4P
6 CCPC
7 0000
8 27HH
9 6678
10 0P7C
11 4UHP
12 7U30
13 3P95
14 41A5
15 NC
16 NC
NC A3U1-3, A3U5-6, and A3U19 are 14-pin package configuration.
u. If ending troubleshooting procedures at this point, disconnect power from HP5517B/C/D Laser Head, set all test
jumpers to their left-most (normal) positions, and replace laser head front panel and side covers.
8-139. Photodiode and Amplifier Troubleshooting
8-140. This procedure assumes that the power supplies are functioning properly. Use a dedicated digital voltmeter.
Do not use the signature analyzer's voltmeter function.
A TILDE ("-") PRECEDING ALL SIGNALS INDICATES NEGATIVE-TRUE LOGIC.
a. Set HTR OK jumper to LO, PHOTO DIODE jumper to TEST, and LIQUID CRYSTAL jumper to PASS.
Is voltage at A3TP16 more negative than-4V? If no, go to step c. If yes, go to step b.
b. Set LIQUID CRYSTAL jumper to ACT. Is voltage at A3TP16 more positive than -1V? If no, go to step
c. If yes, go to step d.
c. Verify that A3U11 (Pin 13) is 0V ±10 mV. If not, replace A3U11. With LIQUID CRYSTAL jumper still
set to PASS, verify that voltage at A3TP16 is 6/11 of that at A3U11 D (Pin 14) and voltage at junction
of resistors A3R20 - A3R22 is 1/11 of that at A3U11D (Pin 14). If not, check A3R6, R1 7, R20, R22,
and R24. Also, A3U12A or A3U12D may be incorrectly loading this node.
d. Amplifier is OK. Check photodiode. Verify that laser beam is on. Set PHOTO DIODE jumper to
NRM. Measure A3TP16 voltage. If it is >+0.5 V then photodiode A4CR1 is good. If it is
approximately -6 V then either the photodiode is shorted or A3U11 is bad. If it is between -0.5 V and
+0.5 V, go to step e.
e. Remove PHOTODIODE jumper and check for diode action between the left hand pin of the jumper
and ground, if diode action is not observed, replace A4CR1. If diode action seems OK, maybe the
problem is caused by not enough light reaching the photodiode. Remove the A6 Sampler Assembly
and inspect the liquid crystal, beam splitters and A4CR1 for dirt, scratches, etc. If O.K., see Liquid
Crystal Troubleshooting.
Table
Table
U2 113
4UHP CCPC
7U30 41A5
■ 41A5
, FP96
4 A3 9 41A5
41A5 FP96
4 A3 9 8U33
0000 0000
7130 3P95
8U33 7U30
6678 41A5
538U 20H3
F9C3 FP96
41A5 CCPC
41A5 41A5
NC NC
NC NC
8-4. Signature
U4 U5
6678 4CCA
0000 FP96
8A5F P861
0000 4UHP
20H3 P861
FP96 4H86
UA4P 0000
0000 41A5
6678 41A5
A0H0 41A5 4 A3 9
88F5 A5P7
0000 P861
538U 0P7C
0000 41A5
4UHP NC
41A5 NC
NOTE
U6 U8
41A5 CCPC F9C3
0000 41A5
F09F 27HH
CU8C 0000
267H 41A5 4 A3 9
9CHA UA4P
0000 0000
4UHP C5U7
4CCA CC8F
0P7C
FF57 41A5
0000 C5U7
9CHA 0P7C CCPC
41A5 41A5
NC NC
NC NC
1119
8816
7130
xxxx
3721
0000
0000
41A5
3721
7U30
0000
41A5
NC
NC