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Model 5065A
Circuit Diagrams, Theory, and Maintenance
c.
Connect a dc voltmeter to A14(1) and adjust
A7R29 for a reading of +4.0 volts on the dc voltmeter.
With this adjustment, the CIRCUIT CHECK
meter
reading (2ND HARMONIC) should be between 36
and 44.
d.
Connect a jumper between XA9 pins 10 and 12
(bottom of chassis). Set OSC FREQ ADJ FINE at 310
and then adjust A14R8 just to the point where the
CONTINUOUS
OPERATION
light
is
extinguished.
Leave the jumper connected for the following checks:
e. Make the following checks of the A14 Logic
Assembly:
1)
Set OSC FREQ ADJ FINE at 250. Then press
the LOGIC RESET button.
CONTINUOUS
OPERATION light should come on. Turn the
OSC FREQ ADJ FINE control slowly cw and
note when the CONTINUOUS OPERATION
light extinguishes.
The OSC FREQ ADJ
FINE reading should be between 300 and
320. If not, repeat step a.
2)
Remove jumper from XA9, reset OSC FREQ
ADJ FINE to 250, and press the LOGIC RE
SET button.
The CONTINUOUS
OPER
ATION light should come on. Leave jumper
disconnected.
3)
Remove the cable from A3J1 (bottom of
chassis).
The CONTINUOUS OPERATION
light should go out after about 5 seconds.
4)
Reconnect the cable to A3J1 and press
LOGIC RESET button. CONTINUOUS OPER
ATION light should come on.
5)
Connect a d c V T V M such as a HP 412A to
the CONTROL jack at the rear of the unit.
6) Adjust OSC FREQ ADJ COARSE slowly ccw.
INTEGRATOR LIMIT light should come on
between +2 and +4 volts as read on the meter.
7)
Adjust OSC FREQ ADJ COARSE slowly cw.
INTEGRATOR LIMIT light should come on
between -4 and -7 volts.
8) Adjust OSC FREQ ADJ COARSE for a zero
reading and then disconnect VTVM.
This
completes the procedure.
5-32. OPTION 002, Standby Power Supply Maintenance
5-33. To insure maximum battery capacity the internal
battery should be "exercised" at least every 90 days.
To exercise the battery, disconnect the instrument
power cord from ac power source.
The front-panel
BATTERY lamp will flash on and off to indicate ac
power line failure. Operate the 5065A for 10 minutes,
then reconnect the instrument to the ac power source.
Set the "Battery" switch to RESET, then to FAST-
CHARGE for at least 16 hours.
5-34. BATTERY lamp should be on for this time period.
At the end of the charge period set the "Battery" switch
to FLOAT.
NOTE
Several exercise cycles may have to be
performed if the internal battery is left in
TRICKLE CHARGE mode for long periods
of time.
The meter reading in BATTERY
should be between 30 and 50.
position
5-35. During FAST CHARGE cycle, connect a clip-on
milliammeter to the orange lead (+) of the internal
battery. Charging current should be 90 to 150 mA. Set
the BATTERY switch to FLOAT position. Current should
be 12 to 34 mA depending on battery condition and
line voltage.
5-36. If the internal battery supply fails to maintain a
charge after several charge-discharge cycles, verify that
the charging current is sufficient (Paragraph 5-35).
If
the current is as listed in Paragraph 5-35, replace the
internal battery.
Troubleshooting information for the
A2 Battery Charger Board Assembly is located with the
A2 schematic in Section VIII.
5-37.
Battery Removal and Replacement
a.
Disconnect instrument from ac and/or dc power
source, and remove top and bottom covers.
b. With instrument on its side remove internal bat
tery fuse (F4) to electrically disconnect the internal
battery. Do not reinstall the fuse.
c.
Unsolder orange No. 14 AWG wire from XA2(4).
d.
Unsolder brown No. 14 AWG wire from capa
citor C1.
e.
Remove 6 Hex-nuts securing the battery cover
and battery to instrument chassis.
f.
Remove the battery and cover.
g.
Unsolder orange wire from the + terminal of the
battery and brown wire from the - terminal of the battery.
h.
Toinstalla new battery perform steps a to g in
reverse order. When step b is performed, reinstall thefuse.
5-38.
CLOCK DISPLAY ASSEMBLY A19
5-39. The A19 LED Clock Display Assembly has no
adjustments and requires no periodic maintenance.
Should repair be necessary, the unit may be removed and
operated on the bench while remaining connected to the
instrument. When operating in this manner, however, the
Clock Display chassis or circuit common must be con
nected to the instrument chassis with a CLIP LEAD OR
JUMPER WIRE.
5-15
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