5. Removalof Electrical Gauge
(a)
Removescrewssecuringoverheadmeter,switchpanelassembly,andlowerassemblyuntil electricalgaugesareaccessible.

(b)
Disconnectwiringfrombackof gauge.

(c)
Removescrewssecuringgaugetopanel;removegauge.

6. Installationof ElectricalGauge
(a)
Placegaugein position onbackof panelassembly.Securewithscrews.

(b)
Connectwiringto backof gauge.

(c)
Positionpanelassemblyandsecurewithscrews.

EFFECTIVITY:
Jan 10/90

PIPER AIRCRAFT PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
B. OverheadMeter and Switch Panel Assembly (continued)
THIS PAGE INTENTIONALLY LEFT BLANK

EFFECTIVITY: 040-999

PAGE26 XX XX XX
Jan 10/90
PIPERAIRCRAFT PA-42-720(AdvancedTrainer) MAINTENANCEMANUAL B. OverheadMeterand SwitchPanelAssembly(continued) 
NO SMOKING (a)  SEATBELTS  DIMMING 
PUSHON 
RECOG  ONON RED ON OFF LO STROBE POSITION LNDG/TAXI EXIT AISLE EXTERNALLIGHTS LTS LTS  EXT PWR OFF  BATTERY MASTER 
HTGRESET LOCKOUT FEATHER QI lJLR0  CLOSE MID IR OiLCOOLERDOOR  ON PtTOPENICE PROTECTION  LEFTENGINE HI ON NOMAL AUTO BLEEDAIR FUEL.PUP  STARTERDISENGAGE MANUAL GEN AUTO STARTER IGNITION  -PANEL-UGHTS LEFT RIGHT PLACARDS DIM BRT CENTER DIM BRT PILOT CO-PILOT DIM BRT DIM BRT ROURESCENT  STARTERDISENGAGE GEN MANUAL STARTER AUIGNITION  Fight ENGINE  PROTECTION  CLOSE OIL COOLER DOOR  WINDSHEILDWIPER 
PANELIGHTS 
OverheadSwitchPanel Figure 2 

EFFECTIVITY:
24-30-00 PAGE27
10/90
24-30-00 Jan
PIPERAIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCEMANUAL

A.  DC Electrical Load Distribution
1.  
MainCircuit Breaker Panel The main circuit breaker panel is located on the pedestal at the center of the flight compartment. It contains50, 100, 200 amp circuitprotectorsprovidingoverloadprotection for various aircraft circuits.

2.  
Removalof Main Circuit Breakers

(a)
Verifymaster battery switch is off and battery is disconnected.

(b)
Removecoverassemblyfrom circuit breakerpanelat base of pedestal. (Figure 401)

(c)
Removescrewsecuring circuit breaker to circuit breakerpanel. Remove circuitbreakerfrom panel.

(d)
Removescrew securing electrical wire to circuit breaker.

3.  Installation of Main Circuit Breakers
(a)
Verify battery masterswitchis off and batteryis disconnected.

(b)
Position required wiresat circuit breaker terminals. Securewith screws.

(c)
Positioncircuitbreakerin circuit breakerpanel and secure with screw.

(d)
Installcover assembly.

CHART 1
CIRCUITBREAKERFUNCTION-MAIN BREAKERPANEL

CIRCUIT BREAKER CIRCUIT
BREAKER VALUE(AM PS) PROTECTED

BATBUSTIE  200 BatteryBus to Battery and Cross Start
NON ESSEN  100 BatteryBus to NonessentialBus
R GEN BUS TIE  200 BatteryBus to Right Distribution Bus
L GEN BUS TIE  200 BatteryBus to Left Distribution Bus
L MAIN  100 Left Distribution Bus to Left Main Bus
R MAIN  100 Left Distribution Busto RightMainBus
ESSEN  100 Left Distribution Busto Essential Bus
AVIONICS NO. 1  50 Left DistributionBusto Number 1 Avionics Bus
L MAIN  100 RightDistributionBus to Left Main Bus
R MAIN  100 RightDistributionBus to RightMain Bus
ESSEN  100 RightDistributionBus to EssentialBus
AVIONICS NO. 2  50 RightDistributionBusto Number 2 Avionics Bus
EFFECTIVITY:

040-999
1

24-60-00 PAGE
Jan 10/90

PIPERAIRCRAFT
PA-42-720(Advanced Trainer)
MAINTENANCEMANUAL

A. DCElectricalLoad Distribution(continued)
TerminalScrew
CoverAsserhbly 
CircuitBreaker  CircuitBreakerPanel 
AttachmentScrew 

MainCircuitBreakerPanel Figure401 NOTE: Referto 24-50-00and24-60-00in the PA-42-720(AdvancedTrainer)WiringDiagram Manualfor schematicsoftheACandDCDistribution.
4. ElectricalPowerDistributionSystemTest
The followingtestsof the electricalpowerdistributionsystem(diodes and circuitbreakerwiring) are requiredat each100hourinspection.
(a) Testfor an opencircuitin busdiodeandwiringinterconnectas follows:
(7.) Pushinessentialbreaker.Pulloutesseial onrightsideofmainbreakerpanel.
If esse ttial or
buspowerislost,diodeorcircuitbreaker
onwireP1F-6 isopenandmustbe
(1.)
Apply
dc
power
using
either
aircraft
engines
orexternal
power.
Checkthat equipment(2.) Pullout leftmaincircuitbreakeron leftside of mainbreakerpanel. Checkthat equipment
　
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