Ivy Biomedical Systems 101NR, Service Manual

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TESTING AND TROUBLESHOOTING
1. Put the oscilloscope on U8 Pin 7.
2.
Adjust RV1 (RASTER) so that the negative peak of the signal at U8 Pin 7 is at -2.5 V.
3.
Press the MENU button on the monitor's front panel.
4.
Adjust RV2 (V GAIN) so that the menu box is 86 mm high.
5.
Adjust RV3 (V BAL) to center the menu box between the top and bottom of the screen.
6.
Press the MENU key again to display the second menu.
7.
Adjust RV8 (DA0) so that the trend line is at the same level as the center horizontal line in the second
menu.
8.
Repeat the above adjustments as necessary.
•
High Voltage Power Supply Board
1.
Adjust the Focus and Intensity adjustments near the top of the High Voltage Power Supply board for the
desired display.
2.
Adjust the Trend Intensity adjustment on the HVPS board to set the trend line intensity separately.
•
Isolation and Leakage Tests
Use a leakage tester or use the ac voltage range on a digital voltmeter to measure across a 1 k
Ω
resistor in parallel
with a 0.15
µ
F capacitor and 10
Ω
resistor.
1.
Measure between a known ground and the monitor's ground post on the rear panel. Wth the line cord
properly grounded, with the ground removed, and with the line cord reversed, the readings should be less
than 20
µ
A.
2.
With the line cord grounded, measure between shorted patient leads and the hot side of the ac line. The
reading should be less than 10
µ
A.
Model 101R/NR Service Manual 45