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Section
V
5-2. LOCALIZING THE TROUBLE.
Model 562A
5-2
When a trouble has been traced to a specific board, make voltagp. meas ure-
ments on base, emitter, and collector of transistors.
On the column board
binaries, transistors that are "turned on" will have approximately t15 volts
on the collector, transistors that are "turned off" will have approximately
-5 volts on the collectors.
Binary tables 5-2 to 5-5 list the states of the
column board binary transistors for various numbers and inputs.
Binaries in
the control board can be checked for switching action with a dc coupled oscillo-
scope.
When a binary changes state, the dc coupled oscilloscope will show a
definite change of dc level.
A vac uum tube voltme ter can be used also.
Figure 5-1 shows the timing voltages and sequence.
Resistance measurements
made between various sockets and connectors may be helpful.
For this, use
the wiring and power supply diagram.
5-3. SEMI-CONDUCTOR REPLACEMENT.
Table 5-3 lists the various transistors and diodes.
When a commercial
replacement type is not listed, the semi-conductor should be ordered from
the Hewlett Packard Company.
When two
rfiJ
stock numbers are listed, the
second number
IS
the correct replacement.
01081-1
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