Welch Allyn Micro Tymp 1, Service Manual

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Section 2.4 Service
MT 1 CALIBRATION PROCEDURE
Step 6
PERFORM PRESSURE CALIBRATION TEST:(taken from A-00849, pg.1,item 6, F&G)
A)
CONNECT UNIT TO MANOMETER OR EXTERNAL PRESSURE SOURCE AT ‘0’ daPa. AT 0 daPA,
IF READING IS AT OR BETWEEN 89 - 8B (HEX), DO STEP B. IF THE READING IS NOT AT OR
BETWEEN 89 - 8B HEX AT 0 daPa, THEN ADJUST R26 TO OR WITHIN
THESE VALUES.
B) PRESSURIZE UNIT TO +200 daPa. IF READING IS AT OR BETWEEN B1 - B3 (HEX), THEN
DO STEP C. IF READING IS NOT AT OR BETWEEN B1 - B3 AT +200 daPa, (HEX), THEN AD-
JUST R31 TO AT OR WITHIN THESE VALUES. REPEAT FIRST TWO STEPS A & B UNTIL
YOU ARRIVE AT THESE VALUES THEN GO TO STEP C.
C) PRESSURIZE TO -300 daPa. IF READING IS AT OR BETWEEN 49 - 53 (HEX), THEN GO TO
STEP #7.
CAUTION: DO NOT MAKE ADJUSTMENTS SOLELY ON THE BASIS OF THE -300 daPa READING. Doing
so will un-do prior adjustments. If the reading IS NOT at or between 49-53 (HEX), DO NOT ADJUST
THE POTS AT -300 DdaPa. DO A OR B BELOW:
A ........ IF THE READING IS ABOVE 53 HEX: (readings will be high if the ‘span’ is too narrow.) TURN R31
CLOCKWISE TO INCREASE the ‘span’ between 0 and +200 daPa IMPORTANT: RE-CHECK at 0
and +200 daPa to verify that unit is within spec.
B ........ IF THE READING IS BELOW 49 HEX: (readings will be low if the ‘span’ is too wide.) TURN R31
COUNTER CLOCKWISE TO DECREASE the ‘span’ between 0 and +20 daPa. IMPORTANT: RE-
CHECK AT 0 and +200 daPa to verify that unit is within specifications.
Step 7
VENT RATE TEST:
MAKE SURE THE MICROTYMP 1 IS IN THE ‘CALIBRATION’ MODE AND IS PRESSURIZED
TO +250 daPa. NOW ENTER THE ‘RUN’ MODE TO VENT THE SYSTEM AND TIME THE
PRESSURE DROP. THE PRESSURE MUST DROP TO 0 daPa WITHIN 1 SECOND.
Step 8
SWEEP RATE TEST: See Figure Step 8 below.
WITH THE PROBE TIP COUPLED TO A 1cc CAVITY, THE SWEEP RATE SHALL BE SET AT
OR BETWEEN 2.40 - 2.55 SECONDS BY ADJUSTING R39. MEASURE FROM LEADING EDGE
OF FIRST PULSE TO LEADING EDGE OF 26TH PULSE (which is 2.40-2.55 sec.)
Figure Step 8 “PUMP SPEED” (from A-01785, Fig.1). pg 16
O
O
PUMP SPEED
OPEN
PRESSURIZATION
PERION
SWEEP
PERIOD
+5 V.D.C.
+5 V.D.C.
ACTUATED
VOLTAGE
AT TPB
START/RUN
BUTTON
VOLTAGE
AT TPBA
VOLTAGE
AT TP7
26