Tachometer Troubleshooting - Piper PA-44-180 SEMINOLE Maintenance Manual

TROUBLESHOOTING TACHOMETER.
TROUBLE
No reading on indicator,
either permanent or inter-
mittent.
Pointer oscillates
excessively.
Indicator changes in
climb.
Pointer goes all the way
to stop, more noticeable
in cold weather.
Pointer jumps at idle.
Tachometer cable breaks.
REMOVAL AND REPLACEMENT OF TACHOMETEER INDICATOR.
Refer to Chapter 34 and Removal of Face Mounted Instruments.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
CHART 7702. TACHOMETER
CAUSE
Broken drive cable.
Loose cable connections.
Rough spot on, or sharp
bend in cable.
Excessive friction in
instrument.
Excessive clearance in
speed cup.
Excessive lubricant in
instruments.
Speed cup hitting rotating
magnet.
Cable bent too sharply.
3H7
REMEDY
Replace cable.
Tighten cable.
Repair or replace.
Replace instrument.
Replace instrument.
Replace instruments.
Replace instrument.
Reroute cable, replace shaft.
7 7 - 1 3 - 0 3
Page 77-05
Revised: May 15, 1989