888-2408-002 5-7
WARNING: Disconnect primary power prior to servicing.
Maintenance and Alignment
NOTE:
Each Isolation Board is programmed for a specific Z-Plane. Therefore, if
more than one Isolation assembly is removed at one time, mark each one as to
its proper location. The programming is a simple jumper selection on the PC
board. The jumper chart is printed on the PC Board next to the jumpers and
can also be found on the Isolation Board schematic if verification is required.
5.5.1.2 Inspection
All of the isolation resistors have a thermistor attached to them with a special epoxy.
Verify that all of the thermistors are firmly attached and that the epoxy has not
cracked as this will give incorrect temperature readings.
!
CAUTION:
BE VERY CAREFUL WHEN DESOLDERING ANY OF THE RESISTORS AS
A LARGE AMOUNT OF HEAT IS REQUIRED. DO NOT PULL VERY HARD
OR THE FEED THROUGH HOLES ON THE PC BOARD COULD BE
DAMAGED.
The resistors should be ordered as an assembly, with the thermistor already attached
as this is very critical to proper transmitter operation.
5.5.1.3 Installation of Isolation Assembly
If a new Isolation Board is being installed be sure to set the ID jumpers to the proper
location as marked on the PC Board next to the jumper pins. The safest method is to
set the ID the same as the board being replaced.
The Isolation assembly should slide back into place fairly easily as long as none of
the pins are bent. Re-install the 4 hex standoffs and the 2 ribbon cables, making sure
that the cables are connected to the same port from which they were removed. Be
careful not to over-tighten the hex standoffs.
5.6 PA Replacement
Since field repair of the Power Amplifiers is not a recommended procedure, the
only option is to replace it (especially during the warranty period). A replacement
PA will include the 1/4 inch thick copper plate under the PC board. Do not remove
the PC Board from the copper plate. When installing the new PA, be sure to apply a
thin but even coating of thermal compound before re-assembly to the heatsink.
Tolerance on the screw holes will assure alignment into the Z-Plane connector.
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