ConMed Hyfrecator 2000 Service Manual page 12

2000
CAUTION: Component damage is possible during service.
Improper service practices may destroy sensitive components in this unit and may void the warranty.
Observe sound, conventional electronic service practices, with particular attention to the following:
• Electrostatic Discharge (ESD): This unit contains ESD sensitive components. Use effective ESD
suppression techniques during all service actions.
• Common-Mode High Voltage: Whenever mains power is applied, and especially when the unit is
activated, high common-mode voltages will appear on all parts of the intermediate circuitry. Connect circuit
common A2TP1 to earth ground before making measurements. Even small currents drawn through earth-
isolated test probes or body capacitance may destroy some sensitive semiconductors.
• Minimize Activation Time: This unit will overheat during continuous activation, especially with low
impedance loads. Observe rated duty cycle. Restrict activation into short circuit loads to less than 5
seconds.
• Component Replacement: Replacement components should be as specified in the parts lists in Section 5 of
this manual. Consult CONMED Technical Services for custom components or acceptable substitutes.
• Housing fasteners: To avoid stripping threads during reassembly, rotate housing screws counterclockwise
with light pressure to find the original threads in housing bosses.
CAUTION: Test Equipment damage possible during service.
This unit produces voltages which may exceed common test equipment ratings. To avoid damage to your
equipment, ensure that their ratings are adequate, with particular attention to the following:
• The common mode peak RF voltage in the intermediate circuitry may rise as high as several kV during
activation. Connect A2TP1 GND to earth to avoid this hazard.
• Peak RF output voltages with respect to earth may exceed 8000 V . Common oscilloscope probes will arc
over at this level and may destroy your oscilloscope input circuits. Do not attempt to measure RF output
voltage unless your oscilloscope probe is adequately rated.
• Use only heavily insulated test leads in good condition on RF output connections. Ordinary test leads
may break down and allow output current to flow through unintended paths.
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