Elecraft XG3 RF - Manual (Page 31)

31
APPENDIX A – JUMPERING THE FUSIBLE TRACE
The XG3 circuit board contains a fusible trace that may burn open to break the connection to the
RF OUT
connector, thereby protecting the rest of the XG3 components if you accidentally apply voltage or RF
power to the XG3
RF OUT
connector. Whether the trace will open before other components in the XG3 are
damaged depends on many variables, including the amount of RF power or voltage applied.
You can check and jumper the fusible trace if it has been burned open as follows. You will need a Number
0 Phillips screwdriver, an ESD-safe soldering station, small diameter rosin core solder, diagonal cutters and
a short length of thin wire.
i
CAUTION! Use an ESD-safe wrist strap or touch a bare metal ground
before touching the XG3 pc board. A static dissipating mat is recommended.
1. Remove the battery cover and battery.
2. Remove the four screws visible on the back cover: two are normally hidden by the battery cover.
3. Lift the rear cover off of the XG3, taking care not to break the two wires leading to the battery
holder clips.
4. Locate the solder pads at each end of the thin trace near the
RF OUT
connector (
J4
on the pc
board) shown in Figure 3.
5. It is not always obvious that the trace has opened. Use your DMM to determine whether you have
continuity between the pads at each end of the trace.
6. If the trace is open, solder a short jumper wire between the pads at the ends of the trace.
7. Reassemble your XG3, taking care to replace the foam pad that holds the pc board in place.
Figure 3. Fusible Trace Solder Pads.