Maintenance— Type 1A1
TABLE 5-5
Transistor Resistance Checks
(excluding FET’s)
Ohmmeter
Connections
5
Resistance Readings
Expected Using the
That Can Be
RXlk Range
Emitter-Collector
High readings both ways (about
200
k n
or higher.
Emitter-Base
High reading one way (about 200
k n
or more). Low reading the other way
(about 400
Cl
to 5
kn).
Base-Collector
High reading one way (about
500 kQ
or more). Low reading the other way
(about
400 Q
to
5 kn).
“Test prods from the ohmmeter are first connected one way to the
transistor leads and then the test prods are reversed (connected
the other w a y ). Thus, the effects of the polarity reversal of the
voltage applied from the ohmmeter to the transistor can be observed.
ponents used in the Type 1A1 result in close spac
ing. An inadvertent movement o f the test prods,
or the use o f oversized prods may cause a short
between circuits.
4. Diodes.
In-circuit checks of diodes can be made quite
easily by measuring the voltage drop across the diode us
ing the voltages on the schematic diagrams as a guide. If
there is doubt whether a diode is defective or not, turn off
the oscilloscope power, unsolder one lead of the diode from
the circuit and check the forward-to-back resistance ratio.
Observe the same precautions as those described when
checking transistors. If the ohmmeter checks prove unsatis
factory, use a good diode checker or replace the diode.
5. Resistors.
Resistors can be checked with an ohmmeter.
Check the Electrical Parts List for the tolerance of the resis
tors used in this unit. Resistors normally do not need to be
replaced unless the measured value is in excess of the speci
fied tolerance.
6. Capacitors.
A leaky or shorted capacitor can best
be detected by checking resistance with an ohmmeter on the
highest scale. Do not exceed the voltage rating of the
capacitor. The resistance readings should be high after the
initial charge of the capacitor. An open capacitor can best
be detected with a capacitance meter or by checking wheth
er the capacitor passes AC signals.
7. Repair and Recheck the Circuit.
If any defective
parts are located, follow the replacement procedures given
earlier in the Corrective Maintenance portion of this section.
Be sure to check the performance of any circuit that has been
repaired or has had electrical components replaced.
® i
5-11
Содержание 1A1
Страница 47: ...Maintenance Type 1A1 670 0075 01 Fig 5 5 Channel 1 Input Amplifier card 5 13 http manoman sqhill com ...
Страница 50: ...Maintenance Type 1AT Fig 5 8 Front of Output Amplifier card 5 16 http manoman sqhill com ...
Страница 128: ...ALT SWEEP SLAVE PULSE CHOPPED BLANKING ALT TRACE SYNC PULSE N 2 0 0 0 0 U P SWITCHING CIRCUIT TYPE IAI PLUG IN ...
Страница 129: ...http manoman sqhill com ...
Страница 130: ...38 ...
Страница 131: ...FIG 3 CIRCUIT CARDS ACCESSORIES CHANNEL I INPUT OUTPUT AMPLIFIER CHANNEL 2 INPUT TYPE 1A1 DUAL TRACE PLUG IN UNIT ...
Страница 134: ...Page 2 o f 2 TYPE 1A1 A p a r t i a l CHAKJKJEL Z INPUT A M P L I F I E R M16 025 1269 ...