Circuit Checks - HP 5065A Operating And Service Manual

Model 5065A
Circuit Diagrams, Theory, and Maintenance
Table 5-3. Circuit Checks
Make checks in the order shown with function switch set to OPER and OSC FREQ ADJ
FINE set to 250.
NOTE
If all meter readings are normal, but CONTINUOUS OPERATION light will not come on,
check: 1) CONTINUOUS OPERATION light bulb, 2) A1 Synthesizer circuit (see foldout,
Page 8-13), 3) A14 Logic Assembly (see foldout, Page 8-47).
CIRCUIT CHECK
Switch Position
BATTERY
SUPPLY
LAMP OVEN
CELL OVEN
OSC OVEN
PHOTO I
Normal Indication
35 to 45
38 to 42
10 to 40
After about 1-hour
10 to 45
After about 1-hour
35 to 45
(for ambient
temperature of
25° C)
After about 1-hour
25 to 50
Nature of Meter Indication
Meter signal supplied from
positive side of internal battery
(Option 002 only) through Terminal
Board A17(1) to S4(A).
Meter signal is regulated +20 V
from A15 Power Supply through
A17(2)toS4(B).
These signals indicate LAMP and
CELL heater currents. These
signals vary with ambient te-
perature. As ambient temperature
decreases the meter signals will
increase, indicating increased
heater current.
These signals supplied by A11
Temperature Control through
A17(3) to S4(C) (LAMP) and
through A17(4) to S4(D) (CELL)
This meter signal indicates power
applied to proportional oven in A10
Oscillator Assembly. Routes
through A17(5) to S4(E). Normal
reading achieved after oven is at
operating temperature (about
1-hour)
Meter signal is A12 RVFR photo
diode current; routes through A7
Assembly, and through A17(6) to
S4(F). Normal reading indicates
Rb
87
lamp is on.
Checks to Make if Reading Abnormal
Standby Power Supply mainten­
ance, Paragraph 5-32.
Check A15 Assembly, foldout page
Check ac fuse.
NOTE: If either reading is full
scale, remove power and allow oven
to cool; then effect repairs. CON­
TINUED OPERATION WITH
METER AT FULL SCALE (AFTER
INITAL WARMUP) CAN CAUSE
DAMAGE TO RVFR ASSY.
Check A11 Assembly, foldout page
Note: If cell oven meter reading is
zero, loss of signal from RVFR can
result
Check dc power connections to A10
Assembly; then check this section
of metering circuit. If all check out,
replace A10.
Remove A7P1 and use meter
such as HP 412A to measure Photo
I directly. Value should be about
twice meter reading; 80^ia = a 40
meter reading. If measured current
and meter reading do not corres­
pond, trouble is in Q1, Q2, or IC1
circuits of A7. If current is much less
than 50Aia: 1) there is node power
to A12 RVFR Assembly at A12J16
or, 2) the A12 RVFR Assembly
is defective.
5-8