1M23N14902
USAGE AND INSTALLATION PRECAUTIONS
FEATURES
Auxiliary safety device that constantly checks the pulse signal from the receiver by means
of a CPU and turns on a fail safe (F/S) function if the pulse is disturbed by interference. When
the power supply voltage drops, a battery fail safe (B-F/S) function turns on and moves the
throttle servo to the preset position (brake or engine slow).
Compact and lightweight design does not affect servo performance.
Responds quickly to erroneous operation by interference, etc. and prevents loss of control of
R/C models.
Quick recall function quickly resets the F/S function by normal servo output signal from the
receiver when the interference, etc. disappears.
Use the FSU2 with AM and FM (PPM) systems. Do not use FSU2 with High Response
System (HRS).
The FSU2 is applicable to four-cell and fi ve-cell NiCd batteries. The activation voltage of
B-F/S function can be selected depending on the batteries.
FOR AM/FM CARS
FOREWORD
Thank you for purchasing an FSU2 Fail Safe Unit. This FSU2 is simple to install - just
connect it between the receiver and servo. However, there are some points that require
attention before use. Therefore, please read this manual carefully and use your FSU2 correctly.
NOMENCLATURE AND SETTING
Monitor Lamp (LED)
Monitor lamp will light at F/S condition and repeat turning on and off at
B-F/S condition.
At normal condition, monitor lamp will blink once or twice depending
on the preset activation voltage of B-F/S function.
It is adequate that the monitor lamp blinks once for a four-cell NiCd
battery
and twice for a fi ve-cell NiCd battery.
Setting Switch (Set)
This is the switch to set the
activation voltage of B-F/S
function and to set the servo
position for F/S function.
Servo Connector
To Receiver
How to check the activation voltage of B-F/S function
1
Connect the FSU2 between the receiver and
the throttle servo.
2
Turn on the power of the transmitter first and
then the power of the receiver. Check the
monitor lamp of the FSU2.
3
It is adequate that the monitor lamp blinks
once for a four-cell NiCd battery and twice
for a five-cell NiCd battery. Otherwise, move
on to the next step, "How to change the
activation voltage of B-F/S function".
How to change the activation voltage of B-F/S function
1
Connect the FSU2 between the receiver and
the throttle servo.
2
Turn on the power of the transmitter first.
Then turn on the power of the receiver while
pushing the setting switch, and then release
the setting switch.
3
Check the monitor lamp of the FSU2 and
confi rm that the number of blinking is properly
set.
* It is not necessary to set B-F/S function every
time as its settings are memorized even if the
power is disconnected.
Use the FSU2 under the following
conditions:
For Nicd battery only
See the [SPECIFICATIONS] section
for more information.
For car and boat
See the [USAGE AND INSTALLATION
PRECAUTIONS] section for more
information.
FAIL SAFE UNIT
INSTRUCTION
MANUAL
How to set the activation position of F/S function
1
Connect the FSU2 between the receiver
and the throttle servo.
2
Turn on the power of the transmitter first.
Then turn on the power of the receiver.
Now, operate the transmitter to adjust the
position of the throttle servo to the position
to which the throttle servo will move when
the F/S function will work.
3
Under this condition, push the setting switch
for about two seconds. Then the LED will
start blinking rapidly.
4
Now, turn off the power of the transmitter,
and check if the throttle servo moves to the
position you have just set.
* It is not necessary to set the position of
the F/S function every time as its settings
a r e m e m o r i z e d e v e n i f t h e p o w e r i s
disconnected. However, it is necessary to
check every time whether the activating
position is correct.
Since the FSU2 has an original B-F/S function,
do not use for aircraft, helicopters, etc. for
the following reason.
* Because the B-F/S function resets itself when
the battery voltage returns to normal, when
the FSU2 is connected to the throttle chan-
nel, if the transmitter throttle stick is set to the
high position when the voltage recovers, the
engine may unexpectedly explode and is very
dangerous. When the B-F/S function is turned
on, the servo of the connected channel is held
in a set position for at least one second. Since
the servo may remain in this state depending
on the battery and load, the FSU2 is unsuitable
for use with helicopters.
Do not use the FSU2 where it will be
directly exposed to water, oil, etc.
* The FSU2 does not have waterproof construc-
tion. When using the FSU2 where it may be ex-
posed to water, exhaust gas, etc., waterproof
it by placing the unit in a leakproof plastic bag
and securing the open end of the bag with a
rubber band.
Do not install the FSU2 where it will be
directly exposed to strong vibration.
Do not install the FSU2 near the
engine or other heat generating
parts.
Do not apply voltage exceeding the
rated voltage. Do not connect the
FSU2 to reverse polarity.
* Repair may be impossible.
D o n o t c o n n e c t m o r e t h a n o n e
servo to the output side of the FSU2.
Never use a cable splitter to connect
multiple servos.
Install the FSU2 where it will not
directly touch other parts, even if the
model crashes.
