Tektronix 3B5, Инструкция по эксплуатации

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Maintenance —Type 3B5
to be operating properly (preferably another Type 3B5 or
similar unit). If the trouble persists after substitution, the
indicator oscilloscope or amplifier unit are defective.
3. Check Instrument Calibration. Check the calibration
of the instrument, or the affected circuit if the trouble exists
in one circuit. The apparent trouble may only be a result
of misadjustment or may be corrected by calibration. Com­
plete calibration instructions are given in the Calibration
section of this manual.
4. Visual Check. Visually check the portion of the instru ­
ment in which the trouble is located. Many troubles can be
located by visual indications such as unsoldered connections,
broken wires, damaged circuit boards, damaged components,
etc.
5. Isolate Trouble to a Circuit. To isolate a trouble to
a circuit, note the trouble symptom. The symptom often
identifies the circuit in which the trouble is located. For
example, no sawtooth output indicates that the Sweep
Generator circuit is probably at fault. When trouble symp­
toms appear in more than one circuit, check all affected
circuits by taking voltage and waveform readings.
Table 4-3 can be used to locate the defective circuit. This
table provides setup information to insure that the controls
are not incorrectly set. Following the setup information, a
series of checks is provided to isolate the trouble to a par­
ticular circuit within the instrument.
After the defective circuit has been located, proceed with
steps 6 — 8 to locate the defective component(s).
6. Check Circuit Board Interconnections. If the trouble
has been isolated to a particular circuit, check the pin con ­
nectors on the circuit board for correct connection. Figs.
4-6 through 4-13 show the correct connections for each
board.
7. Check Voltages and Waveforms. Often the defec ­
tive component can be located by checking for the correct
voltage or waveform in the circuit. Typical voltages and
waveforms are given on the diagrams.
NOTE
Voltages and waveforms given on the diagrams
are not absolute and may vary slightly between
instruments. To obtain operating conditions simi­
lar to those used to take these readings, see the
test conditions in the Diagram section.
TABLE 4-3
Circuit Isolation T'oubleshooting Guide
Preliminary setup
1. Remove the Counter Card and Logic Card.
2. Replace the unit into the plug-in compartment and turn
on the indicator oscilloscope power.
3. Center the amplifier unit position control.
4. Set the indicator oscilloscope intensity control to mid­
range.
5. Set the Trigger Function switch to INT-AUTO.
CHECK PROCEDURE
1. Trace present YES: Apparent trouble may
have been due to incorrect
control settings; if a stable,
triggered display still cannot
be obtained, check the Sweep
Trigger circuit.
NO: Turn indicator oscillo ­
scope intensity control to
maximum; still no trace, pro­
ceed to next step.
2. Check that all readout
bulbs are good
A. Check that MAN light
is on.
Replace any defective read­
out bulbs before proceeding.
YES: Proceed to next check.
NO: Check Operating Mode
Power circuit.
B. Check that the NOT
TRIG'D and s/DIV read­
outs are on.
YES: Proceed to next check.
NO: Check Bright Baseline
stage (Q293, Q295 and Q296)
or the s/DIV and UNCAL
Readout Control stage.
C. Rotate the CAL control
and check that the s/DIV
readout goes off and the
UNCAL readout comes on
(return to CAL).
YES: Proceed to next check.
NO: Check s/DIV and UN ­
CAL Readout Control stage.
D. Set the DLY'D SWP
MAG switch to X10 and
check that the MAG'D
SWP readout comes on
(return to OFF).
YES: Proceed to next check.
NO: Check Delayed Sweep
Magnifier Readout Control
stage.
E. Rotate the MANUAL
TIME/DIV switch through ­
out its range and check
that the "5 ”, “ 1 ” , “2",
“ 0 ” , “m ” and " μ " read­
outs come on.
YES: Proceed to next step.
NO: Check Multiplier and
Decade Readout stages.
3. Check for sweep at TP173
(Time-Base Board) with test
oscilloscope.
YES: Proceed to step 5.
NO: Proceed to next step.
4. Check DC level at TP173 GREATER THAN 40 VOLTS:
Check Sawtooth Sweep Gen­
erator stage (Q 153, D 155,
Q 161, V 1 63 and Q174).
LESS THAN 5 VOLTS: Check
Sweep Gate stage (Q 1 44,
D145, and associated circuit­
ry) .
5. Check for sweep at deflec­
tion plates with test oscil ­
loscope.
YES: Check Unblanking Cir ­
cuit.
NO: Check Horizontal Am­
plifier circuit.
6. Replace Counter Card and
Logic Card. Check that
correct display can be ob ­
tained in Seek and Exter­
nal Modes of operation.
YES: Trouble corrected.
NO: Check Seek Circuit,
Counter Circuit and Opera­
ting Mode Power circuit.
4-4