Tait TM8235, Руководство по обслуживанию

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180 Frequency Synthesizer Fault Finding TM8100/TM8200 Service Manual
© Tait Electronics Limited June 2006
9.1 Initial Checks
Types of checks
There are two different types of initial checks, which are covered in the
following tasks:
■
Task 1 : calibration checks
■
Task 2 : lock status.
Which, if any, of these tasks needs to be carried out depends on the
symptoms of the fault.
Symptoms of Fault
The symptoms of the fault may be divided into three categories:
■
radio fails to power up and system error is displayed
■
lock error is displayed
■
radio is in lock but exhibits transmit or receive fault.
The nature of the display depends on the type of control head as shown in
Table 9.2 .
In the first two cases the checks of Task 1 and Task 2 respectively are
required. In the last case there are several symptoms; these are listed below.
Frequency Bands
Where test procedures or figures differ according to the frequency band of
the radio, the frequency band is given in brackets. The frequency band may
be referred to as either ‘VHF’ (very high frequency) or ‘UHF’ (ultra high
frequency) or identified by the frequency sub-band, such as ‘B1’ or ‘H7’.
The product-code label on the radio body will identify the frequency band
as described in
“Product Codes” on page 17 . A definition of frequency
bands is given in “Defining Frequency Bands” on page 126 .
Table 9.2 Format of error displays by different control heads
Control head Type of error
Lock error System error
1-digit-display control head L E
2-digit-display control head
OL E2
3-digit-display control head OL E2
Graphical-display control head
Out of lock System error