Failure phenomenon

The abdomen probe C5-2 used for Philips iU22 ultrasound equipment is checked in 2D mode, the instrument is normal, when switching to PW mode (pulse Doppler), the instrument reports an error, after restarting the machine, the 2D mode is used normally, and the failure of switching PW mode remains. The superficial probe L11-3 is not affected in any way.
 

Failure analysis

There may be 3 reasons for this failure: 1. Probe failure. 2. Machine system or software problems. 3. The circuit board is faulty.
 

Maintenance

Replace with another C5-2 probe that is in normal use and perform the same operation, and the fault remains. Remove the probe fault. Performing the instrument self-check and software self-checking did not find any problems, restore the mirror backup software on the machine, the fault persists, and eliminate the system and software problems. Considering the reason of the circuit board, in the process of PW mode switching in C5-2, a group of high voltages will dynamically change. The front-end NewAnalog Input Module (NAIM) analog voltage modulation board is responsible for providing the front-end 320MHz master clock, providing the pulse voltage for exciting the probe, and adjusting And calibrate the high voltage pulse, also generate TGCI, TGC2 waveforms, check the overcurrent, overvoltage, front-end temperature at the same time, and manage all the front-end power supply, so it is considered that the NAIM board may be damaged. Disassemble the front chassis, pull out the NAIM board and find that the bottom filter mesh is too dusty, indicating that the board has a problem with heat dissipation. Observing the NAIM board, it is found that the R650 resistor that controls the high-voltage dynamic change part has an abnormal appearance. The resistance is measured with a multimeter to determine that the resistor is damaged. Clean and maintain the machine, replace it with a new NAIM board and restart it after resetting, the fault disappears.