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SECTION 3
Service Infarmafion
3.6
RECHARGEABLE BATTERY
REPLACEMENT
The rechargeable battery, which backs up setup RAM,
does not normally require field replacement. However, if
you notice the instrument no longer stores setups even
after charging the battery, the battery is probably defec-
tive and should be replaced. Follow the steps below to re-
place the battery.
CAUTION
Many parts on the internal circuit boards are
static sensitive. To avoid possible damage,
perform anyrepairoperations
only at aprop-
erly grounded workstation,
and use only
grounded-tip soldering irons and anti-static
de-soldering tools.
1. Disconnect the line cord and all other instruments
from the Model 3930A.
2. REriiVHhi~t6p
and bottom covers (refer to para-
graph 3.3.5 for procedure).
3. Note the positions of the various cables connected to
the control board, then disconnect all cables from the
board.
4. Remove the screws, and release the fasteners that se-
cure the control board to the chassis.
5. Slide the control board towards the front panel until
the jacks clear the rear panel.
6. Remove the control board.
7. Unsolder the battery leads, and cut the sealant that
secures the battery. Remove the battery.
8. Install a new battery, taking care to observe polarity.
9. After soldering, secure the battery to the board using
an electronics-approved silicone or RTV sealer.
10. Install the control board, and connect all cables to the
board.
11. Replace the covers.
12. Turn on the power for 50 hours to fully charge the
new battery.
3.7
REPAIR
Instrument repair may necessary in cases where the in-
strument does not meet the requirements of the opera-
tion check (Section 1) and is probably required if the unit
cannot be properly calibrated.
3.7.1
Factory Service
If the Model 3930A is still under warranty, it is recom-
mended that the unit be returned to the factory or Keith-
ley authorized repair facility for repair or calibration.
When returning the unit for service, include the follow-
ing:
l
Complete the service form at the back of this manual.
l
Advise as to the warranty status of the instrument.
l
Write the following on the shipping label: ATIEN-
TION REPAIR DEPARTMENT.
3.7.2
Power Supply Test Points
Table 3-3 summarizes
power-suppiy
test points, and
Figure 3-8 shows the test point locations. Note that 15V
and 24V supply voltages are reference to TP502, and the
+5V supply is referenced to TP507.
Table 3-3. Power Supply Test Point Summary
Test Point
TlJ501
TIP502
TIP503
Tr504
TIP505
TP506
TIP507
Description
+24V supply
GND (15V, 24V supplies)
-24V supply
+15v supply
-15v supply
+5v supply
GND (+5V supply)
3-10
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