HP 8340B Manual page 264

How to Replace the Battery
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CAUTION
1
f^MM^^i
This assembly contains static sensitive components. Work at
a
bench
equipped with
an
anti-static surface, and wear
a
grounding strap that
provides
a
path to earth ground of
between
1
and 2.5 MQ. Always handle
a
printed circuit board by the edges; never touch the finger contacts.
Do not set the A60
assembly
on
bare
metal; this can short out
and cause
damage to
a
good battery.
1.
Turn the line switch off and disconnect the instrument
power
cord. Wait
3
minutes.
2.
Remove the A60 processor assembly.
3.
Remove the battery
and dispose of
it
properly (see WARNING,
above).
4.
Check the new battery before
installing it;
place
a
10K ohm
resistor across the battery and
mea¬
sure the voltage across the resistor.
The
voltage should be at least
3.4V
(typically
3.6V).
5.
If
the voltage is
correct,
install
the new battery in the processor assembly.
6.
Reinstall the
processor assembly
in the instrument. Reconnect the
power cord,
and turn the
instrument on.
The front panel ENTRY display reads CALIBRATION
RESTORED.
7.
Verify
that TP26 (IBATT)
is less than
3
mV.
A
larger voltage indicates excessive battery drain.
8.
Replace the
top cover.
HP 8340B/41B
Controller Section Repair Procedure F-27