Table of Contents
Advertisement
Model 5065A
Circuit Diagrams, Theory, and Maintenance
b. To check operation of the START AUTO-START
switch, set this switch to the center position and
momentarily disconnect J4 of A10 Oscillator. Note that
with the top cover removed, A10J4 is accessible. With
out a 5 MHz input to A6, there is no A6 1 MHz output
and consequently no 100 kHz output. With A10J4 re
connected, there should be no 100 kHz output until the
START AUTO-START switch is placed at either START
or AUTO-START.
c. To check that the 1 MHz output (J1 and J10)
outputs are within specifications, proceed as follows:
1)
Using the 5065A 5 MHz output as an external
time base input to a counter connect the
100 kHz front-panel jack to the counter
input and check for 100 kHz ± one count.
Disconnect the counter.
2)
Connect the front panel 100 kHz jack through
a 50-ohm feedthrough to an RF voltmeter.
Check for 1.0 to 1.5 volts rms.
Disconnect
the voltmeter and connect an oscilloscope in
its place. Check that the 100 kHz output is
a clean undistorted sinewave.
Disconnect
the oscilloscope.
3)
If a distortion check of the 100 kHz output is
desired, refer to steps 4 and 5 of Table 5-2,
In-Cabinet Performance Check.
TROUBLESHOOTING
NOTE
For troubleshooting or tuning it will be
necessary to mount the A4 circuit card on a
HP
05065-6064
circuit
board
extender.
Power should be disconnect before this
assembly is removed and re-installed.
a. Signal Checks
1) To check Q1, monitor 1 MHz at CR2.
2)
To check Q3, short the 1 MHz input at A4(6)
and then inject 100 kHz at R15 and R16 (1.0
V rms). Check for 900 kHz (X9) at CR2. If
this checks out, leave the 100 kHz connected,
remove the short at A4(6), and check for 100
kHz at R17 and R18 junction. If there is no
regenerative division, check start circuit of Q4
and Q5. In case the dc start circuits is not
working, the start oscillator can be turned on
by grounding TP1 to close Q5 switch.
b. Tuning Adjustments
1)
Connect a 50-ohm termination to the rear
panel 100 kHz output jack.
2)
Connect a BNC tee to the front panel 100
kHz output jack. Then connect an electronic
counter and RMS voltmeter to the VNC tee.
Connect the 5065A 5 MHz output to counter
EXT STD INPUT and set counter for external
standard operation.
3)
Set front panel START-AUTO-START switch
to AUTO-START. Tune A4T1, T2, L6, and T3
for maximum indication on the RMS volt
meter. Counter should indicate 1 MHz ± one
count.
4)
Retune A4T1, T2, L6, and T3 for maximum
output. Output level should be between 1.0
and 1.5 volts.
This complete the 100 kHz
divider tuning.
MODULE REPLACEMENT
When replacing the A4 Assembly after repair or when
a new A4 Assembly is installed, the circuit should be
completely realigned per the preceeding paragraphs.
7-9
Advertisement
Table of Contents
