Troubleshooting - Yaesu FT-208R Maintenance Service Manual

S ERVICING
A FUNDAMENTAL ANALYSIS OF THE TROUBLE
The failure may be caused by one of the following:
1 ) Mechanical defect
2) Electrical defect
Others (Murphy's Law, etc.)
3)
MECHANICAL DEFECTS
1 .
Typical mechanical defects encountered by the technician are:
a) Damage from shock during transportation (remember the unit was probably subjected both to sea
and truck shipment).
Damage caused by vibration in service.
b)
c) Damage caused by forcing stubborn knobs or switches. This difficulty is usually proceded by one o f
the above two defects.
2. ELECTRICAL DEFECTS
Typical electrical defects encountered are:
a) Part(s) failure(s) caused by aging.
b)
Failures caused by improper application of supply voltage, or by voltage spikes. An improper fuse in
use could cause extensive damage to be sustained.
Improper operation (e .g. transistors without load
c)
to the damaged transistor of IC).
d) Loose connections at the power connector or elsewhere caused by cold solder joints, etc.
OTH E RS
3.
Among the miscellaneous types of failures or difficulties encountered are :
a) Antenna troubles - poor connectors, use of cheap coax not made to withstand weather, and sabotage
by neighbors (nail driven through coax, etc. ).
"Cockpit error : " including mislabeled coax lines to coax switch, or attempt to use transceiver on fre­
b)
quencies other than those it was designed for.
Murphy's Law : use of a non-Yaesu microphone with different connections, for example (See page 1 - 1 0)
c)
TROU BLESHOOTING
- this usually points to failure elsewhere, in addition
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