13
WARNING! WARNING! WARNING!
When the amplifier is operated with the top cover removed, hazardous voltages are accessible on the A.C.
line voltage selector and heavy currents are accessible on the exposed terminals of the power supply filter
capacitor and power transistors mounted on the RF amplifier heat sink assembly. Use the insulated tuning
tool provided for any adjustment and do not touch any component within the amplifier when power is
applied. Ensure all primary power is disconnected from the amplifier before attempting equipment
maintenance.
FIRST LEVEL MAINTENANCE
ORDINARY MAINTENANCE
The only regular maintenance needed by the PJ250, is the periodic replacement of the blowers, and the
cleaning of dust filters and any dust accumulated inside the amplifier. The time between overhauling of
the blowers depends upon several environmental factors, temperature, humidity, dust pollution etc.,
Blowers should be checked every 6 months and replaced if noisy. They should be replaced any way after
18 months of service.
SECOND LEVEL MAINTENANCE
CARDS REPLACEMENT
This section contains useful information for card replacement.
WARNING! TO RE-INSTALL CARDS SIMPLY FOLLOW THE REVERSE PROCEDURE.
POWER SUPPLY REPLACEMENT
1) open the top and bottom covers.
2) Remove the four screws (three external and one internal) of the Power Supply section placed
under the RF section.
3) From the bottom of the amplifier, open the power supply section taking care not to break the
wires connected to the card.
4) Disconnect the four fasteners placed on the power supply, and unsolder the other wire.
5) Extract the power supply section.
ALARMS CARD REPLACEMENT
1) Open the top cover.
2) Remove the screws fixing the card on the left side of the amplifier.
3) Take note of the position of wires placed on the rear of the metal box.
4) Unsolder the wires placed on the rear of the metal box.
5) Extract the Alarms card.
DIRECTIONAL COUPLER REPLACEMENT
1) Open the top cover.
2) Remove the fixing screws of the "N" type output connector (1.Fig.2).
3) Unsolder the output cable (RG 303 type) of the low-pass filter placed on the RF section.
4) Take note of the position of the four wires going out of the directional coupler and unsolder them.
5) Extract the Directional Coupler.
TRANSFORMER REPLACEMENT
1) Open the top and bottom covers.
2) Remove the central fixing bolt of the transformer.
To Next Page
Loading...