Ericsson ORION - Transmitter Alignment; Pa Transistor Replacement

LBI-3890
8
11
TRANSMITTER ALIGNMENT
The transmitter consists of synthesizer, exciter and
power amplifier. These have been calibrated at the factory
such that the radio computer automatically adjusts RF
power and modulation deviation, based upon Tracking
Data. The following adjustments can be made by PC
Programming Software:
DO NOT CHANGE TRACKING DATA
UNLESS THE PA MODULE OR LOGIC
BOARD HAS BEEN REPLACED. DO NOT
CHANGE TRACKING DATA FOR ANY
FREQUENCY OTHER THAN THAT GIVEN
IN TABLES 2 OR 3.
CAUTION
1.
Modulation Deviation
- Change Tracking Data using
"MRKMAINT"
maintenance software.Follow the
procedure given in
"TRACKING DATA"
section. Be
sure to record new tracking data and modulation levels.
2.
RF Power
- Set RF power for system (EDACS) or
channel (CONVENTIONAL) in radio personality,
using
"EDACS3"
programming software.
There are no other adjustments to be made on the
transmitter. However, there are components located on the
synthesizer and power amplifier, which appear to be
adjustable. These are summarized as follows:
SYNTHESIZER CV201, CV202, RV201
POWER AMPLIFIER
(20 WATT) RV1
POWER AMPLIFIER
(40/50, 100/80 WATT) RV1
These components have been set at the factory, and
are
NOT ADJUSTABLE
.
ANY READJUSTMENT OF
THESE COMPONENTS WILL VOID THE
WARRANTY OF THIS PRODUCT.
PA TRANSISTOR REPLACEMENT
The RF Power Transistors used in the transmitter
contain Beryllium Oxide, a
TOXIC
substance. If
the ceramic or other encapsulation is opened,
crushed, broken, or abraded, the dust may be
hazardous if inhaled. Use care in replacing
transistors of this type.
WARNING
To Replace the PA RF Transistors
1. Unsolder one lead at a time with a 50-watt soldering
iron. Use a scribe or X-acto

knife to hold the lead
away from the printed circuit board until the solder
cools. Remove the mounting screws.
2. Lift out the transistor. Remove any old solder from the
printed circuit board with a vacuum de-soldering tool.
Special care should be taken to prevent damage to the
printed circuit board runs because part of the matching
network is included in the base and collector runs.
3. Trim the new transistor leads (if required) to the lead
length of the removed transistor.
4. Apply a coat of silicone grease to the transistor
mounting surface. Place the transistor in the mounting
hole. Align the leads as shown on the Outline Diagram.
Then replace the transistor mounting screws using
moderate torque (9.4 kg.cm).
5. Solder the leads to the printed circuit pattern. Start at
the inner edge of the mounting hole and solder the
remaining length of transistor lead to the board. Take
care not to use excessive heat that causes the printed
wire board runs to separate from the board. Check for
shorts and solder bridges before applying power.
Failure to solder the transistor leads as directed
may result in the generation of RF loops that
could damage the transistor or may cause low
power output.
CAUTION