Table of Contents
Advertisement
Model 5065A
Circuit Diagrams, Theory, and Maintenance
2)
Connect the front-panel 1 MHz jack through a
50-ohm feedthru to an RF voltmeter.
Check
for 1.0 to 1.5 volts rms.
Disconnect the volt
meter and connect an oscilloscope in its place.
Check that the 1 MHz output is a clean undis-
torted sine wave. Disconnect the oscilloscope.
3)
If a distortion check of the 1 MHz output is de
sired, refer to steps 4 and 5 of Table 5-2, In-
Cabinet Performance Check.
TROUBLESHOOTING AND REPAIR
NOTE
For troubleshooting or tuning, the A6 As
sembly should be mounted on a HP 05065-
6064 board extender. Power should be dis
connected before this assembly is removed
or reinstalled.
a. Signal Checks
_
1)
To check Q1, Monitor 5 MHz at CR4.
_
2)
To check Q4, disconnect A10J4 to remove 5
MHz and inject 1 MHz (1.0 volts rms) at the
junction of R14 and R15.
Then check for 4
MHz (1 MHz X4) at CR4.
If this checks out,
—
leave the 1 MHz connected, re-establish the 5
MHz connection, and check for a difference 1
MHz CR4 output at the junction of R16 and
R18. If everything checks out so far and there
is no regenerative division, look for a mal
function in the start circuit of Q5 and Q6.
In
case the dc start circuit is not working, the start
oscillator can be turned on by grounding R8 at
pin 6 to close Q5 switch.
b. Tuning Adjustments
1)
Connect a 50-ohm termination to the rear panel
1 MHz output jack.
2)
Connect a BNC tee to the front panel 1 MHz out
put jack. Then connect a counter and RMS volt
meter to the BNC 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 at
AUTO START.
4)
Tune T1, T2, T3, and C21 for maximum indi
cation on the RMS voltmeter. Counter should
indicate 1 MHz + 1 count.
5)
Carefully retune A6, T1, T2, T3, and C21 for
maximum output. Output level should be be
tween 1.0 and 1.5 volts. This completes the 1
MHz divider tuning.
MODULE REPLACEMENT
When replacing the A6 Assembly after repair or when a
new A6 Assembly is installed, the instrument should be
completely realigned per the preceeding paragraphs.
8-39
Advertisement
Table of Contents
