Lower Cable Bundle Replacement

Necessary tools:

• 1/8" and 5/32" Hex Wrench,

• Small Screwdriver

• Diagonal Cutters

• 3/8" Wrench

• Large and small wire ties.

5.3.1 Procedure

1.Shut off the power to the scanner.

2.Take off the table top by removing four screws (two at each end).

3.Remove the head and foot end panels. At the foot end of the scan table unplug the A/C power cable to the scanner.

4.Move the scan arm to the head end of the table.

5. On your new lower cable bundle, use a diagonal cutters to cut the wire ties holding the cable together, also unfold and read the LUNAR SERVICE NOTES attached to the new cable bundle.

6.Lay the new cable bundle flat out on the floor. Locate the end with the (2) 16 pin connectors and the yellow and orange Lemo connectors, this is the end that connects to the bulkhead, this is the end to start the install action from.

7.Locate the bulkhead on the scanner. There are (3) wire ties that hold the cable bundle in place between the bulkhead and the cable track. Before cutting any wire ties note the way the cable bundle is tied down and the way the cable lays before it enters the cable track. The new cable must be fastened in the same position and lay the same way.

8.Carefully cut the (3) wire ties between the bulkhead and the cable track with your diagonal cutters. Disconnect the large RS232 connector (Detector Signal Cable) by unscrewing the two screws on the connector.

9.Next disconnect the two white 16 pin molex connectors. These connectors have a catch lock located in the center of the housing which must be

depressed to disconnect them from the bulkhead.

10.If you try to remove the cable bundle by pulling it back towards the cable track you will notice a 3 conductor gray wire cable tied to the high voltage cable bundle. This wire carries the transverse optical interrupt signal from the front carriage (we will refer to this wire as the OMI cable). To find the location of the OMI board and the front carriage follow the OMI cable. On your new Cable bundle the OMI wire is connected through the bulkhead.

11.To remove the OMI cable push the x-ray tube head all the way to the outside of the scanner (patients left side), then notice the clearance between the front panel and the high voltage cable bundle connecting to the x-ray tube head and the way the cables are tied down as you will need to wire tie them back the same way.

12.Now you can cut the (4) large wire ties and the (2) small wire ties that hold down the high voltage cable bundle and OMI cable. Then you can pull the lower cable bundle back to where it enters the cable track.

13.Next take your small screw driver and pry open (20) of the cable track plastic retaining clips that hold the cables into the track. These clips pivot at the back of the cable track and can either be removed or left in the open position so the cables can be removed.

14.Pull the old cable bundle out of the cable track towards the foot end of the table.

15.Now install the (3) conductor OMI cable from the bulkhead to the OMI BOARD. To do this you must remove the white 16 pin connector from the bulkhead labeled bulkhead 2, this connector is a part of the upper cable bundle and the new OMI cable will connect into this housing. Note the position of the wire tie that holds the upper cable bundle in place and then cut it in order to pull the connector out to install the OMI cable. Note the orientation of the existing terminals in this bulkhead connector as they slide and lock into the connector in one direction only. Where the wires enter the connector each hole is numerically labeled. Put the green wire into hole # 11, and the black wire into hole # 9, and the red wire into hole # 1.

16.Slide the connector back into the bulkhead bracket the way it came out and fasten the upper cable bundle with a large wire tie the way it was before the original wire tie was cut.

17.Route the new OMI cable in the same position as the previous cable and connect it to the OMI board. Then tie the high voltage cable bundle and the OMI cable down to the high voltage cable trough,(there are three large wire ties near the bulkhead, two large wire ties put together to tie the high voltage cables down at the center of the high voltage cable trough, and two small wire ties to anchor the OMI cable down to the Bracket before it connects to the OMI board). Before tightening the wire ties assure that the proper clearances and no stress is applied at any of the connectors or wires. Tighten the center cable ties first (two large wire ties put together and located at the center of the high voltage cable trough). Be sure the high voltage cable bundle does not hit the front panel when the tube head is all the way toward the outside of the scanner (patients left). Then tighten the three wire ties near the bulkhead making sure that the high voltage cables do not hang over into the cut out space on the high voltage cable trough as they may hit the longitudinal motor bracket and cause positioning problems.

18.Take the new cable bundle and connect it to the bulkhead by routing the cable bundle the same way as the replace cable bundle, (note the connectors are labeled bulkhead 1 and bulkhead 2) and fasten the cable bundle down in the three spots between the cable track and the bulkhead with wire ties. Lay the new bundle down into the cable track making sure all the cables lay parallel to each other. Start replacing the clips to the cable track as far as you can. Continue the process: remove a few clips, extract the old cable bundle, add in the new cable bundle, and replace the clips.

19.To finish removing the old and installing the new cable bundle in the lower portion of the cable track you must remove a screw located at the end of the cable track. To do this use a 1/8" hex wrench and a 3/8" wrench. Once you remove the screw you can lift the cable track out of the channel it rides in and finish prying open the remaining clips. Remove the old cable bundle until it reaches the cable entrance hole, where all the cables enter the electrical pan area. Then finish installing the new cable bundle until you reach the cable entrance hole, finish clipping all the clips and then replace the cable track hold down screw (do not tighten the screw at this time).

20.Locate where all the wires from the old cable bundle terminate on the electronics pan. All of the wires are labeled except for the wires that go to the terminal block. Here is a list of wires that must be disconnected before removing the cable bundle from the pan area. SBC(J-5), FOINK(J-17), FOINK(J-12), FOINK(J-14), FOINK(J-5), FOINK(J-8), PMT/AGS(J-11)(J-11 is the yellow Lemo connector), the orange Lemo connector (connected to the H.V. Lemo box), then the last three wires connect to the Terminal block. Write down the number where the orange, blue and yellow wires go to on the terminal block and disconnect them with your small screwdriver. Carefully pull the old cable bundle through the cable entrance hole from the pan area. The old cable bundle may now be discarded.

21.Carefully feed (one connector at a time) the new cable bundle wires through the cable entrance hole into the pan area. Connect the wires to their proper locations.

22.Then move the arm all the way down to the foot end of the scan table. At this time make sure that the Lower cable bundle and the high voltage cable bundle have some slack where the cables enter the cable track near the bulkhead area. Then make sure the cable track has at least 1/8" of clearance from hitting the frame. To adjust this slide the cable track in the trough it rides in to get the proper clearance, then tighten the screw that holds the cable track in place with a 1/8" hex wrench and a 3/8" wrench. Move the arm up and down the scan table to be sure there is nothing wrong with the cable track motion. Leave the arm at the foot end of the table.

23.Leave a little slack in the cables from the cable track to the pan area to allow all of the cables to be routed and wire tied exactly like the original cables.

24.Reconnect the A/C power cord, put the table top, pad, and end panels back on the scanner.

25.Turn on the scan table, computer, monitor and printer. Perform required tests per section 6.9 of the Prodigy Service Manual.