Ultrasound Technologies PD1 series, Service Manual

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Ultrasound Technologies Ltd
Using a pair of tweezers, Introduce noise into pin 4 of J4. Rotate the volume control through
its complete range of travel and observe the audio output from the speaker increases and
decreases accordingly.
4.5
7 3
Transducer
8 7
Transmitter
Set the DC Power Supply to 9Vdc, solder the +ve lead to pin 1 of J1 and the –ve lead to
J1 pin 2 on the board under test.
Switch ON the power supply, check the current being drawn by the board under test is
less than 50ma.
Using the DVM, measure the DC voltage at the junction of C8 and R7, this will be
between 5.2 and 5.8V DC.
Using the oscilloscope connected to the pad TxSig, adjust L1 so that the signal is set to
2.000MHz.
Adjust L2 to set the output to 1.5V pk/pk.
8 8
Receiver
Connect the oscilloscope to the junction of D2 and R12, adjust both L4 and L3 to
maximise the DC signal.
Move the oscilloscope to J1 pin 4, carefully stroke the transducer faceplate and observe a
low frequency signal is displayed on the oscilloscope. The measured output will be a DC
voltage of greater than 5.5V.
4.6
7 4
Velocity Processor
With the oscilloscope set to AC input, adjust the output signal from audio generator to a
frequency of 1kHz and an amplitude of 15mV + 1mV pk-pk. Connect this signal to the
junction of C22 and U5 pin 1.
Set frequency to 10KHz and attach oscilloscope to pin 7 IC3, adjust VR3 until the signal
just changes state from 0V to 5V. The signal will be rough DC.
Using a multimeter, place the +ve probe to the junction of R18, R19 and C19, adjust VR4
until the until the DC level measures 5V.
©Ultrasound Technologies Ltd Page 14 of 32
PD1 / FT120 service manual Issue 3 January 2007