Piper Aircraft Corporation Malibu Mirage PA-46-350P, Airplane Maintenance Manual

Page: 718 / 1956

PAGE 12
Feb 28/07 30-60-00
3K6
PIPER AIRCRAFT, INC.
PA-46-350P, MALIBU MIRAGE
MAINTENANCE MANUAL
E. Deicer (Heater Boot) Wiring Harness
The propeller deicer wiring harness is secured to the propeller counterweight as follows:
(1) Insert the deicer wire harness thru the 9/32 IN. diameter hole in the prop counterweight.
(2) Connect the plugs of the prop deicers and the deicer wire harness as shown in Figure 6.
(3) Install tie strap (P/N MS3367-1-9) between the leads along the length of the plugs. Do not
tighten at this time.
(4) Install both tie straps (P/N MS3367-2-9) under the tie strap installed in the previous step and
around the counterweight. Do not tighten at this time.
(5) Install transflex tubing over deicer wire harness.
(6) Route transflex tubing under both tie straps (P/N MS3367-2-9) and tighten tie straps.
(7) Tighten the tie strap around the plugs.
(8) Install the terminals on the deicer wire harness.
(9) Install the terminals of the harness to the screws on the spinner bulkhead and tighten the lead
clip over the harness.
(10) To assure balance of the propeller assembly, the original balancing weights or their equivalents
must be reinstalled. The weights must be left in the original position on the propeller hub. The
restrainer and weights should not interfere with any part of the propeller assembly under any
condition. If for any reason balance weights were removed, reinstall safety wire on screws. The
deicer wire harness must be installed on the propeller as just described.
3. Testing
A. Resistance Test
To determine incorrect resistance, short or open at the brush-to-slip ring contact, disconnect
harness at the timer and use low-range ohmmeter to read resistance from each deicer circuit lead
(Pins C, D, E and F of harness plug) to ground; it should read .58 to .67. If this reading is not
obtained, disconnect the deicer lead straps to measure deicer resistances individually. Individual
deicer should be 1.15 to 1.33. If first check is off limits but second check is satisfactory, trouble is
probably in the brush-to-slip ring area; if the second check is off limits, the deicer is damaged and
must be replaced.
B. Ammeter
(1) Using the Ammeter
Whether in flight or during ground testing, the ammeter can be used to indicate the general
nature of most electrical problems. The troubleshooting chart is primarily based on the use of
the ammeter and assumes that the user does understand all normal operating modes of the
system.
NOTE: When troubleshooting, first use the “ammeter test,” below, and “heat test” (see
Inspections - 50 Hour) to determine which circuits are involved. Use circuit diagram for
assistance to check voltages or continuity.
(a) Excess current reading on the ammeter always indicates a power lead is shorted to
ground. Thus, when trouble of this nature is found, it is vital that the grounded power lead
be located and corrected.
(b) A considerable number of timers that have been returned for repair proved to be fully
workable when tested. Accomplish the test described under “BFG Timer,” below, before
concluding that the timer is defective.
(c) Defective wiring in propeller mounted components may be indicated by normal current
readings in ground checkouts (propeller not rotating) but low current with propeller rotating
at cruise RPM.