HP 5065A Operating And Service Manual page 346

M o d e l 5065A
C i r c u i t D i a g r a m s , T h e o r y , and M a i n t e n a n c e
ment. Remove supply and reconnect cable to
" - E F C " jack.
A10 REPAIR CONSIDERATIONS
If repair or adjustment of A10 is required, the assembly
must be removed from the HP 5065A. Once removed, the
A10 assembly can be operated independently by con­
necting two power supplies. Set one power supply for +22
to +30 Vdc (450 mA maximum current) and connect to
the "+24" input. Set the other supply to +20 Vdc
(approximately 50 mA) and connect to "+20" input.
Power supply (-) terminals are connected to A10 chassis.
An alternate method is to obtain power from the H P
5065A. Using clip leads, connect the A10 chassis to the
5065A chassis. Connect the "+24" terminal on A10 to
XA15(4), and the "+20" terminal to XA15(6).
With the A10 removed and operating outside the
instrument, troubleshooting is relatively easy. Power
supply voltages can be measured on A10A3 sockets. If
power supply is defective, remove oscillator assembly
A10A1 to gain access to power supply assembly A10A3.
A10A3 will operate normally with A10A1 removed.
IF A10A1 IS FOUND TO BE DEFECTIVE, THE
ENTIRE A10 ASSEMBLY (05065-6094) MUST BE
REPLACED. THE A10A1 10 MHZ OSCILLATOR IS
NOT FIELD REPAIRABLE.
The A10A2 (Frequency Divider/Amplifier Board
Assembly) and A10A3 (Power Supply Board Assembly)
are both repairable to the component level. If the A10A3
is replaced, the factory-selected resistor A10A3R11 from
the defective board, or a resistor of equivalent value,
must be installed in the new board. The value of
A10A3R11 must reflect the value as noted on the A10A1
oscillator itself.
ADJUSTMENTS
There are four adjustments in the A10 assembly: A10A1
output amplitude, frequency, EFC gain, and A10 output
level. Assembly A10A1 output amplitude adjustment is
covered in the 10811A/B Operating and Service Manual.
Frequency adjustment is covered as part of the 5065A
operating procedure. A10 output amplitude and E F C
gain adjustments are covered below.
OUTPUT AMPLITUDE ADJUSTMENT
a. With A10 operating outside the 5065A as pre­
viously described, connect A10 " I V " output
through a 50-ohm feedthrough to a n oscilloscope
vertical input.
b. Adjust A10A3R8 for an oscilloscope display of 3.1
Volts p-p (1.1 Volts rms).
c. Remove connections to A10 and replace in H P
5065A.
A10 ASSEMBLY REPLACEMENT
The HP 5065A does not require internal adjustments
following replacement of oscillator assembly A10. After
installation is completed, follow the tum-on procedure
in Figure 3-2 of the Operating and Service Manual.
8 - 5 2 (SERIES 2120A)