Modifications for the ICOM - RogerK

Author: Burt I. Weiner - biwa@pacificnet.net.MODIFICATION.NETI have an ICOM R-7000 that has had an intermittent display from the time I purchased it. It has been back several times forrepair at an authorized service center. The problem would re-appear after a few weeks. I got tired of sending it back and decidedto live with the problem. After a while it became so bad I became too annoyed to live with the problem and decided to track itdown for myself. I did discover the actual cause of the problem and after making repair the display has been 100 percentreliable.The problem turned out to be the flat ribbon type cable that runs between the display and the display board. Checking theconductors of the ribbon cable with a meter was misleading because of the intermittent nature of the problem. The repair was alot simpler than I had imagined. I did not replace or remove the ribbon cable but instead connected parallel conductors across it.The process is simple if you have experience with delicate stuff. It's necessary to remove the display board and the display. Firstand most important - UNPLUG THE RADIO! Remove the top and bottom cover of the radio. Remove the screws on the left andright side of the front panel brackets that attach it to the main chassis. The front panel will hinge down to about a 45 degreeangle. Support it in that position. Remove the 2 screws from the back of the display board. Carefully remove the display boardand the metal shield on the back of the board. Carefully swing the board back revealing the component side. Unplug the"dimmer" control plug on the right side of the display board. I found it necessary to cut the tie wraps on the wires connecting tothe display board. Be very careful not to cut any of the conductors. Once you've done that you can swing the display board backeven farther. Next, remove the two flat head screws on the top of the front panel. This releases the bracket that holds thedisplay against the front panel. Again, be very careful in handling the display. You will notice a foil shield along the bottom of thedisplay ribbon cable. Carefully peel it away exposing the ribbon cable and both ends.I rotated and positioned the board and display so that the pins on both were facing up with the soldered side of the ribbon cabletowards me. I used stranded wire from a ribbon cable out of a computer for the jumper wires. DO NOT USE SOLID WIRE! Makethe jumpers one at a time. I stripped about 1/16th of an inch of wire, tinned it and then soldered it to one end. Before cuttingthe other end I dressed it to length following the ribbon cable's "curve" and then cut the other end. Do not make it to tight orleave too much slack. Then I stripped 1/16th of an inch of wire, tinned and soldered it to the other side. Be careful not to bridgeany of the connections together. You will note that four of the points, two on each end are connected together. I used only asingle conductor for these. Take your time doing this. Check each jumper as you put it in by following the trace in the ribboncable, which is quite visible, to be sure you are not cross connecting somewhere. JUMPER ALL OF THE CONDUCTORS! If one isintermittent, then the others are or soon will be.When you are finished and just before you start to re-assemble things, carefully clean the display and the inside of the displaywindow with Windex. I used a clean piece of old t-shirt.Rotate the board and display back into position for re-assembly. Re-position the foil shield under the (new) conductors andribbon cable. I did not replace the tie wraps previously cut but carefully positioned the leads so they do not become pinchedunder brackets during re-assembly. When installing the display make sure that the fingers at the bottom of the display bracketgo under the display easily. Reverse the procedure described above for re-assembly of the rest of the radio. Don't forget toreplace the "dimmer" control plug on the right side of the display board once the board is mounted.Since making this repair the display has worked without failure. The sensitivity of the receiver is as good or better than beforeindicating that the noise output from the display is still well contained. If you have been suffering from the annoying intermittentdisplay as long as I had been this will be well worth the effort.Burt, K6OQK - biwa@pacificnet.netBurt I. Weiner AssociatesBroadcast Technical ServicesGlendale, California - U.S.A.biwa@pacificnet.net.MODIFICATION.NETK6OQKThis modification is read 846 times.top of page