SECTION 2
PRELIMINARY BENCH TEST FOR MICROTYMP 2 23641
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Purpose of test: Tests MicroTymp 2 for: 1 Leaks, 2 Vent rate, 3 Noise,
4 Recharge, 5 Inactive current drain, 6 Active current drain. These tests help
prevent aborted calibration cycles in Calvin, thus saving time. The technician
can resolve MT2 handle problems
before starting the recal process.
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How Performed: Perform tests in series in numerical sequence.
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When Performed: Before recalibration.
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Required Equipment: Welch Allyn Calvin Recalibration system, Digital Volt Ohm
meter, Pressure Box T-5657 or equivalent pressure source (400 dPa max, with 1
dPa resolution on digital display), fully charged battery.
Test 1 Leaks
1.1 — Open MT2 and remove battery.
1.2 — Momentarily apply 7.2 VDC across valve coil to latch valve closed.
See FIG 1.2 for polarity.
1.3 — Connect Pressure Box (T-5657) pressure tube to MT2 probe tip while
valve is latched closed.
1.4 — Adjust pressure of T-5657 to 200 dPa and observe leak rate.
Must leak less than 10 dPa in 5 seconds.
1.5 — Throw Pressure/Vent switch to V (vent).
1.6 — Throw Select switch to Negative. (This will cause meter to read positive with
negative pressure.)
1.7 — Throw Pressure/Vent switch to Pressure
1.8 — Adjust pressure of T-5657 down to -400 dPa and observe leak rate.
Must leak less than 10 dPa in 5 seconds.
1
Apply 7.2 Volts D.C. momentarily to close valve.
Valve will 'latch' and hold closed position.
Figure 1.2 Closing Valve for leak check procedure.
Probe end
Valve
— 7.2 v +
Empty Battery
compartment
