Cosman G4 Radiofrequency Generator Service Manual (SPI 11291 Rev A)
Section 16
Record Pass/Fail on the Test Traveler
If not the unit must be returned to Cosman Medical for evaluation and repair.
16.15 Audio calibration adjustment
Select Stim mode
Set the on screen audio volume control to maximum
Set the load to 1K
Verify that the on screen volume control increases the volume with each press of the increase button,
and decreases with each press of the decrease button to the off position.
Verify that the audio frequency varies with the load resistance.
Record Pass/Fail on the Test Traveler
If not the unit must be returned to Cosman Medical for evaluation and repair.
16.16 Stimulator tests
Attach the 330 load (500 in parallel with 1k ) to the generator outputs for E1
Attach an oscilloscope across the load
Press the Stim button
Rotate the Output Control knob to minimum
Press the ON button
Increase the output until the display reads 3.00 (max)
Note: There will be a 1v peak RF sign wave riding on the square wave signal, in order to get the
measurement, adjust the scope to normal trigger on the waveform in peak detection mode, and then
change to average mode. This will help remove the RF and allow a more accurate reading.
Verify that the oscilloscope displays a biphasic square wave with peak amplitude of 2.9 to 3.0v
Replace the 330 with a 250 (2x500 in parallel)
Verify that the output is greater than or equal to 2.7v
Replace the 250 with a 1k
Verify that the output is less than or equal to 3.3v
Record Pass/Fail on the Test Traveler
Record the final value measured by the Oscilloscope across the 330 on the Test Traveler
Change the stimulator output units setting to Current
Replace the 1k with the 500
Rotate the output control knob to minimum
Press the ON button
Increase the output to until the display reads approximately 9.98mA
Verify that the oscilloscope displays a biphasic square wave with peak amplitude of 4.5 to 5.5v
Replace the 500 with the 1k and verify that the output is greater than or equal to 9v
Record the final value measured by the Oscilloscope across the 500 on the Test Traveler
Measure each of the available Stimulation Rates (PPS) and Durations (mS) and record on the Test
Traveler
With the output knob up off minimum press the On Button, then turn the output up to maximum
Verify that there are no stim pulses present on the oscilloscope
Attach the 500 load to each of the other generator outputs in turn.
Verify that each output produces the correct stimulation frequency and duration only when selected.
If the values differ substantially from those listed above the unit must be returned to Cosman Medical for
evaluation and repair.
16.17 Maximum RF output test
Attach a 100 load to the generator outputs for E1 using a CB112-TC cable and a TC Electrode
Attach an oscilloscope across the load
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