Service manual

Maintenance
4-3
Mechanical Safety Check
Verify that the unit is clean, the screws are tight, the connector pins are not damaged, the case is not
damaged, and that there are no frayed or pinched wires or cables. If the unit is mounted, check that
the mounting hardware is tight.
Test Specifications
* Measurement taken from the power cord third wire ground to the most distant ground attachment.
Electrical Safety Checks
Electrical leakage safety testing protects the patient from electrical shock, especially microshock.
Microampere current values can cause fatal arrhythmias in electrically susceptible patients. A
patient is deemed electrically susceptible when connected to monitoring equipment.
Perform the case current leakage test and the ground resistance leakage test with the module
installed in a Spacelabs Medical monitor and in accordance with current regulatory requirements.
Before performing these tests on the module, verify that the monitor itself passes the case current
and ground resistance leakage tests.
Monitor Case-to-Ground
Leakage current from the monitor case lugs through the AC cord to ground should be less than
300
µA for U.S. (500 µA internationally), regardless of the power ground configuration.
Resistive Plug-to-Ground
Test the display assembly and DC power supply(s) for ground resistance:
1. Temporarily attach the module housing and measure the resistance from the AC power cord
third wire ground to a chassis location, such as the equipotential post on the rear of the
display assembly or at the outer shell of the DB-26 of the most remote housing.
2. Verify that the resistance is less than 200 milliohms.
Table 1: Test Specifications
Mains to Chassis Leakage
Mains
Resistance
International (IEC 601.1) US (UL 2601)
500 µA - normal condition, ground
attached (AC connector to chassis)
300 µA - normal condition, ground
attached (AC connector to chassis)
200 milliohms*
500 µA - single fault condition, open
ground or reverse polarity
300 µA - single fault condition, open
ground or reverse polarity
200 milliohms*
WARNING:
• Before starting a safety test, ensure that a patient is not connected to the
equipment under test.