panel. (4.) Place fluorescent fixed dimming switch in overhead panel to DIM position. (5.) Rotate all instrument lighting dimmerrheostats fully counterclockwiseto the lowest setting
(See24-30-00, Figure 2).
NOTE: An assistant is required to adjust the power supply, located forward of the pilot's instrumentpanel, at station 0.00.
EFFECTIVITY:
040-999 33-00-00

Jan 10/90

PIPER AIRCRAFT
PA-42-720 AdvancedTrainer)
MAINTENANCEMANUAL

A. GeneralCompartment(continued)
2. FluorescentGlareshieldLighting (continued)
(c) Adjustmentof Glareshield FluorescentLightingInverter(continued)
(6.) Apply 24 Vdc bus power, being careful not to cause short circuits and read voltage at exposedends of the coax cables.
(7.) Have assistant adjust potentiometer FV 2 (Figure 501), with a fully insulated slot head
screwdriver,to 375 Vac at ends of both coax leads.
(8.) Turn off 24 Vdc bus power. Reconnect coaxial leads.
(9.) Disconnect coax lead (marked 1 LBD 105064BB) at copilot's position and coax lead (marked 1 LBD 103064BB) at pilot's position.
(10.)Againapply 24 Vdc bus power and have assistant adjust the Bright/Dim potentiometerto
375Vac at ends of both coax leads.
(11.)Turnoff 24 Vdc bus power. Reconnectcoax ends.
(12.)Disconnectcoaxleads marked 1 LFV 201064AA and1 LFV 202064AA at the pilot's position.
(13.)Apply24 Vdc bus power and have assistant adjust the FV 1 potentiometer
to 375 Vac at the coax disconnectedends. (14.)Turnoff 24 Vdc bus power. Reconnectremainingtwo coax leads. This completes inverter adjustments.
Dim Adjustment

Inverter  Max.  Max.  Max. 
FV1  D/B  FV2 
ADJ. 
A 

FluorescentLighting Inverter/Control Unit Figure501
(d)FaultIsolationGeneralGuidelines
With dimmer controls at full brightness and the entire EL lighting inoperative, check 24 Vdc supply to EL inverter/dimmer unplug that panel
control unit. If only one EL panel is inoperative, and test for 140 Vac, 400 Hertz, at panel connection. Workback through the harness to the inverter, if no voltage is present. If voltage is present, bench test EL panel with 110 Vac, 60 Hertz power. In all cases, conventionalpoint to point fault isolation methodsapply.
EFFECTIVITY:

PAGE2 040-999 Jan10/9033-00-00
PIPERAIRCRAFT

PA-42-720 (Advanced Trainer)
MAINTENANCEMANUAL

A. General Compartment (continued)
3. Dimmer Control Assembly
Thedimmer control assembly is located in the forward baggage compartment area around FS
0.00. The dimmer control is located on the underside of the floorboard access panel at the aft left corner (when facing forward) of the forward baggage compartment.
(a) Removal of Dimmer Control Assembly
(1.) Remove electrical power from aircraft by disconnecting battery. Open baggage
compartment door. (2.) Raise floor liner in the aft left comer (when facing forward) of baggage compartment. (3.) Remove screws securing access panel. (4.) Lift access panel. Disconnect electrical connector from dimmer control. (5.) Remove mounting screws securing dimmer control to access panel. Separate panel from
dimmer control.

(b)
Repair of Dimmer Control Assembly

Replacement parts are ordered from the parts catalog. See Figure 801 for dimmer control circuitry.

(c)
Installation of Dimmer Control Assembly

(1.) Position dimmer control assembly on access panel. Secure with appropriate hardware.
(2.) Connect electrical connector to dimmer control assembly.
(3.) Place access panel into position and secure.
(4.) Replace floor liner.
(5.) Secure baggage compartment door.
(6.) Connect battery and perform an operational check of lighting system.

4. Dome Light
(a)
Removal of Dome Light

(1.) Remove four screws securing dome light assembly in headliner.
(2.) Let light assembly hang from headliner.
(3.) From behind light assembly, remove light bulb.

(b)
Installationof Dome Light

(1.) Insert new bulb into socket.
(2.) Position light assembly in place on headliner.
(3.) Secure light assembly with appropriate screws.

EFFECTIVITY:

040-999 PAGE 3
33-00-00Jan
PIPER AIRCRAFT

PA-42-720 (Aavanced Trainer)
MAINTENANCEMANUAL
A. GeneralCompartment(continued)
Conn E494 1 3
Fixed Dim. Avionics Dim.
Ctr. Pnl.
28 VDC

R. Pnl.
Control

R.H.Pnl.
28 VDC
Placard
Control

Plac
28 VDC

All Transistors Are Motorola 2N6282
Dimmer Control Assembly Circuitry
Figure 801

EFFECTIVITY: 040-999
　
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