Does your Beechcraft Alternator Out
light flicker or come on and you confirm that your alternator is working just
If it does this then you might have a cracked
alternator out light printed circuit board. This circuit board is subject to all
the engine vibration that occurs out there and has been found to have a tendency
PS: If you even THINK you need an alternator
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Modified Aircraft Accessories.
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Here's a fix for the circuit board contributed
by Beech Lister Eric T.
Above is a photo of the repaired mini-PCB Board. The
resistor is on the other side of the PCB. The copper wires at either end were
Initially I took the circuit board and checked for
continuity and it seemed that the traces on the circuit board cracked causing
the open circuit. I then took some thin gauge copper wire, and soldered a loop
from where the resistor passed through the circuit board to the terminal
mounting pads at the ends the circuit board. The notion being to provide a more
mechanically robust conductor from the resistor to the terminals at the ends of
the circuit board.
Here's a pirep from F33 owner Shep J., regarding his experience with a flickering Alt Out light:
"I have CE-559 and my Alternator OUT light would
sometimes flicker, and sometimes stay on for long periods despite the
alternator charging normally. The cause was an old fuse that had a loose
filament that would vibrate and make an intermittent connections. Try
replacing the fuse first, it is easy and cheap. If that doesn't do it
check the AUX terminal at the alternator for a loose connection. The
fuse block is located on the firewall on the pilot side." As seen below.
A great article in the October 2008 ABS
Magazine, written by John Collins on page 10998 and 10999, discusses the history
of the alternator out lights and their components and how they work in the system.
Some very interesting Beechcraft parts,
available at RAPID,
outlined in this article that could be of interest to you and your mechanic in
repairing or retrofitting your system with
alternator out lights are:
P/N 36-380000-1 (14V Alternator Out Sensor)
P/N 36-380000-3 (28V Alternator Out Sensor)
$138 (as of 5/20/2014)
P/N 36-380000-11 (Baron Replacement Alternator
P/N 55-3025-1 S (Replacement PCB Kit) $108
Here is the pdf for the
Lamar Alternator Out Relay
Here is more info on the Lamar sensor from a
Beech Lister, Mike Ter.:
The basic circuit of the Lamar alt inop sensors is:
Green wire gives ground for warning light through the sensor's black wire.
Raw voltage from the alternator stator post (aux) is supplied through the red
wire. When the voltage from the red wire meets the voltage from the green
wire, the ground circuit is disabled for the green wire and therefore the
warning light goes out. The red wire from the alternator is usually
protected by a fuse. If you ground the wire that attaches to the green
one and your lamp lights up, the circuit is ok.
If the lamp does not light up when the sensor is correctly
wired then you sensor is bad. The Lamar PN for the 28v sensor is A-00258-2.
You can get them at Aviall.
It retails for about $120.
For more info on
an Alternator Out Light Install click