Agilent Technologies 5517B Operation And Service Manual page 99

b. A1CR1 is in series with the -1 5 Volt line.
c. A3L1 and A3L2 are in series with the ±15V power supplies.
d. There should be >200 Ohms from +1 5V to ground.
e. If A1F1 opens (+15V line), check for open in A1R11, A1R12, or thermally caused damage to
WHT/ORN wire lead to |A1J3 (Pin 2)1, or excessive current being drawn by the High Voltage Power
Supply. (See High Voltage Power Supply Troubleshooting in paragraph 8-87.)
f. Power supply components are located on both A1 and A3.
8-150. Reference Receiver Troubleshooting
a. With power disconnected from the HP 5517B, the -REF ON jumper to LO, and HTR OK jumper to
HI. Apply power to HP 5517B. Does the READY LED eventually start blinking then remain on
continuously? If no, see HP 5517B Trouble Isolation Procedure, paragraph 8-74 and procedures
recommended therein.
b. Are TTL- level signals present at A3U16 (Pins 1 and 3) at a frequency of between 1.5 and 2.0 MHz?
If so, the reference receiver may be working properly. If not, trace the signal path from A3U17 (Pin
16), through A3Q6, to A3U16 [Pins 5, 6, and 7 (A3TP22)] and check for the following:
A3U17 (Pin 16): 0.3 to 0.7 Volt square wave at the Reference frequency of 1.5 to 2.0 MHz.
A3TP22: TTL-level square wave at the REFerence frequency of 1.5 to 2.0 MHz.
Al J2 Rear Panel Connector:
Figure 8-19.
Figure 8-19. REFrerence Signal Waveforms
Monitor Pins E and F with an oscilloscope. Waveforms should be similar to those in
Figure 8-19 oscilloscope settings are as follows:
Time/Division: 0.2 microseconds/division
Volts/Division: 2 Volts/division
Coupling: DC
NOTE