CSP-HMI-3MD Helicopters, Inc.
MAINTENANCE MANUAL
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95-00-00
Page 501
Revision 7
The information disclosed herein is proprietary to MD Helicopters, Inc.
Neither this document nor any part hereof may be reproduced or transferred to
other documents or used or disclosed to others for manufacturing or any other
purpose except as specifically authorized in writing by MD Helicopters, Inc.
Copyright © 1999−2016 by MD Helicopters, Inc.
INSTRUMENTS
ADJUSTMENT/TEST
1. Instruments Adjustment/Test
Certain instruments, such as altimeters and
vertical speed (rate of climb) indicators, are
equipped with simple adjusting means. The
barometric correlation adjustment should not
be adjusted in the field; changing this adjust
ment may nullify the correspondence between
the basic test equipment calibration standards
and the altimeter. These adjustments should
be accomplished by qualified personnel, using
proper test equipment and adequate reference
to the manufacturer's maintenance manuals.
2. Instrument Cluster Three−Pack
Calibration Check
(Ref. Table 501 or Table 502) Instrument
cluster calibration information is provided for
the convenience of the calibration facility.
Polarities must be observed and instrument
face should be vertical during calibration
checks.
NOTE: When making calibration checks, re
move supply voltage and variable resistor
from circuits when adjusting and measuring
value of variable resistor.
Special Tools
(Ref. Section 91−00−00)
Item
Nomenclature
N/A Heat gun
N/A Ohmeter
N/A Power supply, 14.5 ±0.3 Vdc, 2 amp
N/A Lamp, No. 328
N/A Variable resistor, 0-90 ohms
N/A Variable resistor, 0-750 ohms
N/A Test ammeter
N/A Battery, dry cell, 1 volt
N/A Potentiometer, 5 watt
(1). Early Model Instrument Clusters:
Use calibration charts (Ref. Table 501).
Test voltage should be 14.5 ±0.3 Vdc.
Indicator scale error shall not exceed
five percent of full scale value at any
time.
(2). Late Model Instrument Clusters
:
Use calibration charts (Ref. Table 502).
Test voltage should be 28 ±0.3 Vdc.
Allowable indicator error is included in
the calibration charts.
Table 501. Instrument Cluster Three−Pack Calibration Charts −
369D26415 Unit (Early Model)
Step Graduation Ohms
Time
(min)
Tolerance
(degrees)
Remarks
Fuel Quantity Gauge
NOTE: Use 0 − 90 ohm variable resistor across terminal studs 1 and 8.
1 2 (200
pounds)
59 5
2 F (Full) 88 ±4 Ascending pointer
3 2 (200
pounds)
56 ±3 Descending pointer
4 E (Empty) 1 −2 Descending pointer
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