Removal Of Final Xyz Amplifier Unit A2 - Fluke Autoranging CombiScope PM3370B Service Manual

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8.5.4

Removal of Final XYZ amplifier unit A2

ATTENTION: On the XYZ unit there are parts that carry high voltages. If working on the unit under
- Remove the screw that secures (and grounds) the unit to the bottom chassis plate.
- Disconnect the 4 wires that lead to the CRT (The X- and Y-deflection plates): this action must be
done carefully to avoid damage to the side connections of the CRT. For correct reinstallation refer
to the wiring diagram in chapter 4.2.
- Bend out the two clamping lips that secure the unit at the top side. The unit is loosened now.
NOTE: The unit can be put now in an inclined position as shown in figure 8.3. Measuring on the SMD-
component side in working condition is possible then. Measuring the output wires that lead
to the X- and Y-deflection plates is possible with a 10 kΩ damping resistor between
measuring point and probe tip. This avoids oscillations.
- Unplug two ribbon cables and take the unit out of the chassis.
- Unplug the delayline connector.
Figure 8.4
live condition cannot be avoided, it must be done by a qualified technician who is
aware of the dangers involved.
Final XYZ amplifier in inclined position
CORRECTIVE MAINTENANCE PROCEDURES