5-15.
ALC ADJUSTMENTS (Cont’d)
7. Note indication on the DVM. This value is
VvM
for high band and will be used for calculations in
step 8.
8. Calculate “Corrected Video Resistance in Hi Band,”
RvH,
as follows:
RvH
(RvM
—
100) >< 24000/(RT + 4000)
where:
RvH
=
Corrected Video Resistance in High Band
RvM
VvM
=
Value measured in step 7 above.
Thermistor Resistance measured in step 4 above.
9. Use the Value of RvH found in step 8 above and select the resistance values for A25R36 and
A25R37 from Table 5-6.
10.
Disconnect the high band detector All cable W27 from the SMB-to-BNC adapter and connect the
low band detector A12 cable W26 to the adapter as shown in Figure 5-45.
11.
Connect the DVM at the output of the Power Supply and check that the output is still at 5.00
±
0.01
Vdc. Move the DVM connections back to the SMB-to-BNC adapter as shown in Figure 5-45.
12. Note indication
on the DVM. This value is
VvM
for low band and will
be used for calculations in
stepl3.
13. Calculate “Corrected Video Resistance in Low Band,”
RvL,
as follows:
RVL
(RvM
—
680)
X 24000/(RT + 4000)
where:
RvL
Corrected Video Resistance in Low Band
RvM
VvM X
200 Ohms/mV
VvM
Value measured in step 12 above.
RT
=
Thermistor Resistance measured in step 4 above.
14. Use the value of
RvL
found in step 13 above and select resistance values for A25R109 and
A25R115 from Table 5-7.
Table 5-6.
Selected Values of High Band Temperature Compensation Resistors in A25
RVH (Ohms)
A25R36 (Ohms)
A25R37 (Ohms)
800-870
9090
6190
870-950
8250
5620
950-1050
7500
5620
1050-1160
6810
5110
1160-1270
6190
4640
1270-1380
5620
4220
1380-1490
5110
4220
1490-1600
4640
3830
Adjustments
5-91
HP 8340B/41B