(b)(4).The sample was returned for evaluation.A visual exam was performed and there were no defects observed.Functional testing was performed and the unit was connected to 110vac.The unit passed the initial power connect test and navigated through the power-on self-test (p.O.S.T.) with no issues.During the temperature display accuracy test the unit displayed the correct temperatures and properly alarmed in the high temperature scenario.The unit was prepared for the functional bench test where water, an adult breathing circuit (880-36kit), 2-3 lpm of air pressure, and a 382-10 concha smart water column was connected to the unit for a real time operational scenario.During the pre-operational self-tests a red wench appeared and the unit alarmed.The unit was opened and the resistance was measured across the thermal switch and the thermal fuse.The resistance across the switch measured 0.2 ohms, which is within the normal operating range of 0.2-0.4 ohms.The switch measured 0.1 ohms which confirms it is not blown.Based on the above, the only other component that would cause a red wrench failure is the power control board.This could have resulted from a faulty component on the board or a loose solder connection.Based on the investigation performed, the reported complaint is confirmed.Functional testing revealed a faulty power control board.It is unknown what caused this control board to fail.It could have been a faulty component on the board, or a solder joint got loose during shipping and handling.Based on the sample returned and the complaint description the root cause cannot be determined.
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