Agilent Technologies 5517B Operation And Service Manual page 45

5-13. Test Equipment Required. The reference temperature adjustment requires the following test equipment:
5-14. Preliminary Procedure
5-15. This adjustment must be made with the laser tube at room temperature. If the laser High Voltage Power
Supply (A2) or heater have been on, allow at least two hours with ±15Vs off before performing this procedure.
Regardless of whether power is on or off, observe the safety precautions in paragraph 5-4 and proceed as follows:
Figure 5-1)
(See
a. Remove the HP 5517B Laser Head covers by following the procedure outlined in paragraph 8-57.
b. On A3 change the HEATER jumper from NRM to OFF.
c. Apply power to the Digital Voltmeter and set its controls to the 1 Volt DC range. Connect the positive
lead of the Digital Voltmeter to A3TP11, and connect the negative lead to A3TP1.
d. If the HP 5517B power has been disconnected for at least 2 hours, reconnect ±15 Volt system power
supplies and continue with the adjustment procedure in paragraph 5-16.
5-16. Procedure. To adjust the reference temperature, proceed as follows:
a. Check that the Voltmeter reads between +0.2V and +0.3V. This voltage is V(A3TP11).
b. Record value of V(A3TP11) measured in step 5-16(a).
c. Calculate the heater adjust set point using the following equation:
V = 1.285 x V(A3TP11)
set
d. Connect Digital Voltmeter positive lead to A3TP15. Connect the negative lead to A3TP1.
e. Check that the voltage at A3TP15 equals V
SET TEMP (See Figure 5-1).
f. If not, Note and record the SET TEMP voltage in the "ADJUSTMENT RECORD" table located at the end of
this section.
g. Disconnect ±15 Volts from HP 5517B Laser Head.
h. On A3, change the HEATER jumper back to NRM (left-most position). Remove the test equipment leads, and
reinstall the laser head covers.
5-17. Laser Tube Current Measurement
NOTE
A TILDE ("~") PRECEDING A SIGNAL NAME INDICATES NEGATIVE-
TRUE LOGIC LEVELS.
5-18.. This procedure measures the laser tube current. A current of 3.5 milliamperes ±0.2 milliampere must be
measured. If not, the power supply must be replaced with a new power supply.
5-19. Test equipment required. The laser current measurement requires the following test equipment:
Clip-On DC Milliammeter, HP Model 428B
JMP 3
Digital Voltmeter, HP Model 3435A
, +1 millivolt as calculated in step c. If not, adjust A3R16
set
LIQUID
CRYSTAL PHOTO DIODE
JMP 5 JMP 9
TEST