BC Biomedical DA-2006, Service Manual, Page: 155 / 171

C 9
OPEN BOX CALIBRATION
1. Perform the Closed Box Calibration procedure.
2. Remove the screws on the bottom of the UUT.
3. Open the UUT but leave the ribbon cable connected between the power supply
board and the analog board. You will need access to the test points and
potentiometers on the analog board while the UUT is powered.
4. Enter the Calibration menu as shown in steps 1-4 of the Closed Box calibration
procedure.
5. On the UUT, Change the A/D Input Parameter to “Low Range”
6. Adjust Potentiometer RA2 so that the A/D Counts displays 0
7. Connect 4.00 VDC to TP3(+) and TP1(-) on the analog board.
8. Adjust Potentiometer RA1 on the analog board so that the A/D Counts display
shows 2000.
9. Reverse the connections to the TP3 and TP1 terminals. A/D Counts display should
show –1980 to –2020 counts.
10. Change the A/D Input parameter to “High Range”.
11. The A/D Counts should show –396 to –404 counts.
12. Reverse the connections to the TP3 and TP1 terminals.
13. The A/D Counts should show 396 to 404 counts.
14. Remove the 4.00 VDC from TP3 and TP1.
15. Set the A/D Input parameter to “Pace 0”.
16. Adjust Potentiometer RA3 so that the A/D Counts shows 0.
17. Connect 10.0 VDC to TP7(+) and TP6(-) on the analog board.
18. The A/D counts should show 98 to 102.
19. Set the A/D Input to “Pace 1”
20. The A/D counts should show 392 to 408 counts
21. Set the A/D Input to “Pace 2”
22. The A/D counts should show 1568 to 1632
23. Replace the screws on the bottom of the UUT.