A loss of receiver sensitivity (6-30dB) may be caused by shorted switching diodes in the Signal unit (X57-1000-xx). The following procedure will increase the capability of the unit to withstand high RF voltage levels.
Signal unit (X57-1000-xx)
- Replace Signal unit jumper J27 with an XZ-070 Zener diode.
(PCB coordinate C-1, see figure 2.)
- Change diodes D15 through D33 from BA2B2's to 1S2588's. Change only the defective diodes when making the repair.
- Figure 3 show a circuit that is capable of withstanding antenna input levels of up to 50 Watts. Use this on units that may be subject to high levels of RF. (This is an optional change that may not be done in-warranty.)
Installation time for this procedure is ½ hour or less.