Smiths RVI.1000 SERIES, Инструкция по эксплуатации

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SYMPTOM FAULTS TREATMENT
Permanent reading
on tachometer with-
out a pulse being
fed in.
Transistors TR1 & TR2
Triggering Coil T
Resistor R1
TR1, R4, R5, R6 and R8
R4
R8 & R5
R6
TR2
With the supply ON short point D to
earth and check that the meter reads.
The meter should not read when point A
is shorted to earth. When A is
earthed measure the voltage at E. If
it is less than 1.5V change T11, if
more than 1.5V change TR2.
Measure resistance of the coil
between + terminal and B. The
correct value is 120 ohms. If
Correct proceed to Rl.
With the supply OFF check the
resistance between E & B. Should be
between 517 ohms and 423 ohms.
With the supply ON measure the
voltage at E. If the voltage is
less than 0.2 volts proceed to
check TR2. If it is greater
than 0.2V the fault lies in TR1, R4,
R5, R6 or R8.
With the supply OFF check the
resistance between E & -6V terminal.
This should be 750 -900 ohms.
With the supply OFF check the
resistance between A & G. On
adjusting the potentiometer the
resistance should vary between 6K and
22K. The value of R5 should. read
5.1K.
With the supply OFF check resistance
between G & -6V terminal. This
should be between 16 ohms and 20
ohms. If R4, R5, R6 and R8 are
satisfactory change TR1.
With the supply ON short B to earth. If
the meter still reads,
replace TR2 and then check that the
meter reading falls to zero. If
after shorting B to earth the meter
does not fall to zero, recheck TR1,
R4, R8, R5 and R6.
S.14