Welch Allyn Tycos - Calibration Procedure

Welch Allyn Inc. Aneroid Sphygmomanometers Service Manual
Revision A
Welch Allyn Inc. Page 13 of 40
3.2 Calibration of the Hand Gauge
1. Attach the pneumatic tubing of test equipment to the gauge.
2. Ensure that the valve of the gauge is closed. Place gauge in to fixture
(T107569)
3. Increase pressure on the gauge to 250 mmHg. Allow the pressure to stabilize
for 15 seconds. Check leak and ensure that the leak is no greater than 3
mmHg in 15 seconds.
4. Remove bezel, crystal, pointer and dial.
To set the tension:
5. Tighten all screws.
6. View sector gear and ensure proper position (i.e. right edge of sector gear
should align with mark on base of movement).
7. If sector gear not aligned properly, loosen the capsule nut using a 3/8”
wrench and adjust the sector gear by turning the capsule until sector gear is
in correct position per step 5. Tighten capsule nut.
8. Loosen sector stop lug and pull toward bottom of gauge.
9. Using your left index finger, push the sector gear all the way to the post and
hold that in position.
10. Place tension setting tool (T119628) onto pinion at the 9 o’clock position.
11. Rotate tool clock wise to the 3 o’clock position.
12. Release sector gear and continue rotation to the 6 o’clock position sector
gear should be moving during this step).
13. Bring lug back to correct position and lock into place.
To set the span:
14. Place Test Dial onto gauge. Place pointer onto pinion. Rotate dial until
pointer is at “0” at the bottom of the gauge.
15. Apply 320 mmHg to the Gauge.
16. Release pressure to 300 mmHg to the gauge.
17. If point is less than 300, Place calibration tool (T106845A) into the radius
plate in slot above screw. Pull calibration tool toward bottom of gauge
moving the sector gear upward until pointer reached “300.” Release pressure
and check “0” point.
18. If point is greater than 300, Using the calibration tool (T106845A) positioned
between the sector gear and radius plate on the left of the movement, rotate
the tool clock wise until pointer is at “300” (this brings the radius plate down).
Release pressure and check “0” point.
19. If not at “0” upon release of pressure, rotate test dial until pointer is on the “0”
mark of test dial and re-apply 300 mmHg. Repeat steps 14-17 until span is
set.