Maintenance
HF SSB Transceiver 9323/9360/9390/9780 Technical Service Manual 5-3
• Heatsinking—When soldering heat sensitive components to the circuit board,
where possible use long-nosed pliers or some other form of heatsinking on the
leads of the components.
• Thermal conduction—When replacing transistors that are mounted on
heatsinks, ensure there is thermal conduction between the heatsink and the
component being replaced. This can be achieved by cleaning the mounting
surfaces then re-coating them with a thermal conduction compound such as
Jermyn Thermaflow A30.
Track repair
Broken or burnt sections of printed circuit track may be repaired by bridging the
damaged section with tinned copper wire. The section where the repair is to be
made must be cleaned before soldering (observe the precautions detailed on
page 5-2, Unsoldering).
Integrated circuit replacement
It is often possible to unsolder and remove components from the board without
damage to the component or the tracks on the board. However, integrated circuits
with many connections, mounted on double-sided circuit boards with plated-
through holes, are almost impossible to remove intact and the operation is likely to
damage the circuit boards. To replace these components, their leads must be cut
individually until the body of the component can be removed. Individual leads
must be unsoldered and removed. The excess solder must be removed before
inserting the replacement component (see page 5-2, Component replacement).
Transmitter precautions
When making measurements of the low level stages of the exciter, it is advisable
to remove the drive to the PA and Filter PCB. The supply voltage is applied to the
PA at all times when the transceiver is switched on. Caution should be exercised
when connecting probes.
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