Service manual

Chs 00 - 07 and 90
HI Measurements 1. Make Hardware Connections
– Turn mainframe power OFF
– Connect DMM leads as shown in Figure 2-3
– Turn mainframe power ON
2. Measure Channel 00 HI Resistance
– Send *RST to multiplexer
– Send CLOS (@nn00) to close chan 00, where nn = card #
– Trigger the DMM with TRIG SGL and note reading
– Send OPEN (@nn00) to open channel 00
– Subtract measured value of R20 from DMM reading
– Enter the result in Table 2-2 for Channel 00 HI
3. Repeat for Channels 01 - 07 HI and Channel 90 HI
– Repeat steps 1 and 2 for channels 01 - 07 HI and 90 HI
– Use CLOS (@nncc) and OPEN (@nncc), where nn =
card # and
cc = channel # (omit leading zeroes in nn)
– For Channel 90 HI, subtract combined value of R20 + R26
Ch 00 - 07 and 90
LO Measurements
1. Make Hardware Connections
– Turn mainframe power OFF
– Connect DMM leads as shown in Figure 2-4
– Turn mainframe power ON
2. Measure Channel 00 LO Resistance
– Send *RST to multiplexer
– Send CLOS (@nn00) to close chan 00, where nn = card #
– Trigger the DMM with TRIG SGL and note reading
– Send OPEN (@nn00) to open channel 00
– Subtract measured value of R21 from DMM reading
– Enter the result in Table 2-2 for Channel 00 LO
Figure 2-3. Ch 0-7 and 90 HI Measurements Connections
Chapter 2 Verification Tests 25