User's Manual

EX7100 Technical Manual - Module Descriptions
©1999 Exicom Technologies (1996) Ltd 7-8 Issue 3 - May 2001
9. Remove the thermal pads and the insulating bushes and discard them. Inspect the
new pads and bushes carefully for any foreign matter. Small specks of dirt or metal
filings can cause the pad to be punctured when the semiconductors are clamped
down.
10. Carefully remove all foreign matter from the mating surfaces of the new Power
Supply’s semiconductors and the heat-sink contact area.
11. Align new pads with the holes in the heat-sink contact area. Place the new power
supply PCB in its cavity and align the board with its mounting holes. Replace the nine
semiconductor mounting screws and bushes. Do not fully tighten the screws.
12. Replace the six M4 PCB mounting screws and washers. Tighten the screws carefully
(do not over tighten as this can strip the internal screw threads). Tighten the
semiconductor mounting screws.
13. Using a multimeter, measure the resistance from the tab of each semiconductor to
the aluminium casting. All readings should be more than 400Ω (ensure that PL1 is
not plugged in when measuring). If any reading is lower, remove the heat-sink
components and check them all carefully for the cause of the short circuit. Caution:
do not proceed with the installation until this insulation test has been passed
successfully or the power supply will be damaged.
14. Replace the six ferrite beads (two per wire) on the main power cables and insert into
terminal block TB1. Ensure that the polarity is correct. Carefully tighten the screws of
the terminal block.
15. Re-connect the cable loom plug into PL1 and the cable into connector SK6.
16. Re-connect the remote on/off switch loom to SK301. Ensure that all
cables are run as
they were prior to removal.
17. Inspect the EX7100 terminal to ensure that it is free of foreign material. Remove and
clean as required.
18. Connect the antenna to the terminal. Check the external
DC supply fuse, to ensure it
is not blown and replace if required (refer to Section 2.6.1 for fuse types and ratings)
19. Apply power to the EX7100 rear panel and switch the terminal on. Measure the
output rails with a multimeter and verify that they are all within the specifications as
detailed in Table 7.1.
20. Replace the bottom cover, taking care to tighten every screw. No screws should be
left over at the end of the job.
21. Re-install the EX7100 into its rack and re-connect all necessary power, signalling and
antenna cabling.