Safety Precautions; Check Power Line Voltage; Measure Line Voltage; Measure Isolation Transformer Secondary Voltage - Hologic QDR 4500 Technical Manual

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QDR 4500 Technical Manual

SAFETY PRECAUTIONS

There are a number of safety precautions that MUST be observed when servicing the QDR 4500
systems.
HIGH VOLTAGE: Voltage levels that can be injurious or fatal are present through the QDR
4500 systems. The line voltage (100, 120, 230 volts) is supplied to the power console. The X-ray
source unit contains 140kV as well as other AC and DC voltages. The pedestal motors use 230
volts regardless of the line voltage. Use caution when checking, calibrating and troubleshooting.
Always trip the main breaker when replacing components.
X-RADIATION: Service personnel are required to wear a dosimeter. Do not leave the system
unattended in SUSQ (SURVEY mode).
ESD PRECAUTIONS: To prevent damage due to ESD (Electrostatic Discharge), you must take
precautions when handling components. Remove any charge from your body by wearing an
approved and properly grounded wrist strap. Keep PCBs in their ESD protective bag until you
are ready to install them. Treat defective PCBs as new to prevent any additional damage.

CHECK POWER LINE VOLTAGE

Hologic strongly recommends that the QDR 4500 be powered from a dedicated power line. See
the product specifications in Section 1 for power requirements.

Measure Line Voltage

With an AC voltmeter, before plugging in the QDR 4500, measure the voltage at the outlet the
unit will be plugged into. The measured voltage must be within ± 10% of the voltage shown on
the power label (located where the power cord attaches to the unit). The QDR 4500 has a built-in
step up/down isolation transformer which can be re-strapped to accommodate other voltages if
necessary. See Figure 3-16 for the most common configurations of the isolation transformer.
There are two standards for conductor color coding. The North American standard specifies the
BLACK conductor as LINE and the WHITE as NEUTRAL, while the International standard
defines the BROWN conductor as LINE and the BLUE as NEUTRAL. On newer units, the
primary side of the isolation transformer is on the left and the secondary is on the right.
Note: Be sure to change the label if you restrap the transformer.
Note: Enter this information into The Radiation Measurement Report (see page 3-28).

Measure Isolation Transformer Secondary Voltage

After plugging in the instrument and switching on the main breaker, measure the voltage at the
accessory outlet located at the bottom rear corner of the power console with an AC voltmeter.
Note: Do not try to measure the voltage at the "AUXILIARY X-RAY ON" outlet, as this outlet
is only energized when X-rays are on. The voltage should be between 110 VAC and 130
3-18