MTHTrains BIG BOY User manual

MTH BIG BOY
ARTICULATED STEAM ENGINE
OPERATING INSTRUCTIONS
Thank you for purchasing the MTH die-cast Big Boy steam locomotive.
The engine’s die-cast body and tender are built to ¼ inch scale proportions
from the original Union Pacific prototype and is designed for operation on
any O-72 or larger O Gauge layout. The engine is compatible with most
standard AC transformers, (see page 34 for a complete list of compatible
transformers and wiring instructions) and is completely compatible with
most other 3-rail locomotives, rolling stock and accessories.
The locomotive and tender are equipped with the ProtoSound® digital
sound and train control system which contains several deluxe features that
are simple and fun to operate. Each feature is described among the
following pages which should be read before the engine is operated. For
those of you who can’t wait to get started, the Quick Start Basic Operating
Instructions found on pages 3 and 4 should be read so that you understand
the basics of the operating system.

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MTH Big Boy Operating Manual
Table Of Contents
QUICK START - BASIC OPERATION(All 3-Rail Models) 3
PROTOSMOKE™ UNIT OPERATION 4
PROTOSOUNDS® OPERATINGINSTRUCTIONS 5
ProtoSound® DCRU® Reverse Unit Operation (All 3-Rail Models) 5
Whistle Operation 6
Bell Operation 6
ProtoCoupler™ Operation 7
Enhanced Neutral Steam Sounds 8
Squeaking Brake Sounds 8
Tips On Using The Squeaking Brake Sounds 9
Freight Yard Sounds (FYS) 10
Activating and Triggering Freight Yard Sounds 10
Tips On Using FYS Features 15
Self-Recharging Battery Backup System 16
Replacing The ProtoSound® Battery 16
ProtoSound® Volume Adjustment 17
USING “RESET" TO PROGRAM PROTOSOUNDS™ 18
Entering RESET Options 18
Setting The Engine Volume 19
Programming For A Separate Bell Button Controller 20
Programming For Squeaking Brake Operation 20
Programming For Whistle In Neutral Operation 21
Programming For ProtoCoupler™ Operation 22
Programming For FYS Operation 23
Activating Remote Lockout Control 23
ResettingAll ProtoSound® Options To Factory Default 24
REVERSE UNIT LOCK-OUT OPERATION 25
Locking The Engine Into Forward or Reverse 25
Unlocking The Engine 25
Locking The Engine Into Neutral 25
OIL & LUBRICATION INSTRUCTIONS 27
TRACTION TIRE REPLACEMENT INSTRUCTIONS 28
LIGHT BULB REMOVAL & REPLACEMENT 29
TROUBLE SHOOTING PROTOSOUND®PROBLEMS 30
ProtoSound® RESET Feature Chart 33
Transformer Wiring Chart 34
SERVICE AND WARRANTY INFORMATION 35
HOW TO GET SERVICE 35
LIMITED ONE YEAR WARRANTY 35

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MTH Big Boy Operating Manual
QUICK START - BASIC OPERATION
The MTH Big Boy contains state-of-the art electronics with several
built-in automatic features for incredibly realistic operation. Despite these
advanced features, the Big Boy is easy to operate with any compatible
standard AC transformer (see the compatibility chart on page 34). All
models are equipped with an operating smoke system that should be primed
with smoke fluid before operating. Adding 15 - 20 drops of fluid through
the smoke stack should be sufficient. If you choose to not prime the units
with fluid, turn the smoke unit switch located under the leading truck to
theOFFposition. (See Figure 1) This will prevent any damage from
occurring to the smoke unit when running the engine without a primed
smoke unit. For more information see the section on page 4 on Smoke Unit
operation.
The Big Boy model is controlled by a
ProtoSound® DCRU® electronic reverse
unit. The reverse unit operates in the same
manner that all reverse units function by
using forward, neutral and reverse states
that are entered each time the throttle is
turned on and off or by using the
transformer direction switch (if so
equipped).
The reverse unit is designed to ignore dirty track, dead spots on switches
or minor short circuits without
disrupting the engine operation,
even at slow, prototypical speeds.
Before the engine can be operated
however, the reverse unit plug that
extends out of the tender must be
inserted into the receptacle at the back of the boiler cab as seen in Figure 1.
Once the plug is inserted, the throttle on the transformer can be advanced.
You will see that only the engine’s lights come on and that on ProtoSound
equipped engines, two dings from the sound system will chime followed by
the steam compressor pump sounds. The engine does not run. This is
known as the RESET state and is explained in more detail beginning on
Page 6. The ProtoSound® DCRU® will not power the motor until the
throttle is turned OFF and then ON again. At this point, the engine will
now function just like any other electronic or mechanical E-unit.
Use first hole for O-72 operation.
Use 2nd hole for display and 96 inch
or larger diameter curves.
Plug Tender Plug into
Boiler Socket at back of cab.
Figure 1: Plugging in the tender harness
RESET
Neutral
Reverse
Neutral
Forward
Figure 2: ProtoSound® DCRU® Cycle Phases

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MTH Big Boy Operating Manual
PROTOSMOKE™ UNIT OPERATION
The Big Boy contains a self-powered smoke unit that outputs a steady stream of smoke
through the smoke stack on the roof of the engine. The ON/OFF switch located next to the
trailing truck must be in the ON position in order for the smoke unit to function. See Fig.
3below.
The smoke unit is essentially a small heating
element and wick which soaks up and then “cooks" a
mineral oil-based fluid that omits a harmless smoke.
The smoke is then forced out of the stack via a small
electric fan which runs at a constant speed. However,
the smoke intensity can be varied by increasing the
transformer voltage setting. The higher the setting,
the more intense the smoke output.
For best results, we recommend that you add 15 -
20 drops of ProtoSmoke™, Seuthe, LGB or LVTS
fluid before you run the engine. If you don’t choose
to add the fluid, then the smoke unit switch should
be turned off. Failure to either add the fluid or turn the switch off could lead to damage to the
smoke unit heating element and or wicking. Add the fluid through the smoke stack hole. After
adding the fluid, gently blow into the stack to eliminate any air bubbles. Do not overfill the
unit as overfilling can cause the fluid to leak out and coat the interior engine components.
When the smoke output begins to diminish while running the engine, an additional 10-15
drops of smoke fluid should be added or the smoke unit switch should be turned off. When
storing the engine for long periods of time, you may want to add at least 15 drops of fluid to
keep the wick soaked with fluid and prevent it from drying out. After removing the engine
from storage, it is advisable to add another 25 drops of fluid, letting the wick soak up the fluid
for 15 minutes prior to operation.
MAINTENANCE
CAUTION: Operating the engine without
smoke fluid and with the smoke unit switch in
the ON position can damage your smoke unit
wick, causing the wick to become hard,
blackened and unabsorbant around the
heating element. When this occurs, it may be
difficult for the wick to soak up the smoke
fluid resulting in poor or no smoke output. If
that occurs, we recommend that you inspect
and/or replace the wick taking care to not
run the engine without fluid in the future.
You can inspect the wick to see if it needs
replacement by removing the smoke unit
inspection cover from the body as seen in
Fig.4. After removing the chassis and inspection cover screws lift the inspection plate away
and inspect the wick. If the wick is darkly discolored and hard, it should be replaced.
Figure 3: Smoke Unit Switch
Figure 4: Inspecting The Smoke Unit

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MTH Big Boy Operating Manual
PROTOSOUNDS® INSTRUCTIONS
The MTH ProtoSound® digital sound and train control system provides
the operator with unprecedented realistic operation on your model railroad.
In addition to actual Big Boy engine, CD-equivalent 16-bit digital sounds,
you get the following features:
1. ∗Built-In ProtoSound® DCRU® Reverse Unit * Authentic Steam Whistle Sound*
Authentic Steam Bell Sound* Squeaking Brake Sound* Freight Yard Sounds*
Operating Remote Controlled ProtoCoupler™* Self-Recharging Battery
Back-Up System With Automatic Battery Shut-Off* Remotely Controlled
Reverse Unit Lock-Out* Remotely Adjustable Steam Engine Chuffing Volume*
Authentic Steam Engine Neutral Sounds*
Each feature is described among the following pages. Though the system
is easy to use, we encourage you to read the instructions thoroughly.
PROTOSOUND® DCRU® REVERSE UNIT
As mentioned in the Basic Operating section, the engine is controlled by a
ProtoSound® DCRU® reverse unit that contains the standard
forward-neutral-reverse states found on most reverse units. However, as
described earlier, when power is first applied to the track, the reverse unit
begins in RESET or what seems like a neutral state. Power must be
interrupted again to get the locomotive to enter the forward state. It is this
first RESET state that gives ProtoSound® its unique, remote controlled
functions. The system will enter RESET whenever power to the track is off
for three or more seconds. NEUTRAL will be referred to as the state
between Forward and Reverse.
ProtoSounds® is equipped with a microprocessor, that, depending on the
amount of memory it is allotted, allows the user to utilize several remotely
activated functions. In the simplest terms, ProtoSounds® has its own
“Computer" controlling these functions. In fact, the power of this
microprocessor is the same as that of a 286 desktop computer! In order to
access many of these remotely controlled functions, the user must be in the
RESET state to do so. RESET is entered anytime power to the locomotive
has been off for more than 3 to 5 seconds. When the engine first enters
RESET, the microprocessor initiates a system check to determine if the
system, transformer and engine are operating correctly. This takes
approximately 2.2 seconds during which you will hear the engine’s
compressor sounds begin. In order for ProtoSounds® to properly initiate

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MTH Big Boy Operating Manual
the system check, do not advance the transformer throttle past 10 volts
when you first enter RESET, wait for the compressor sounds to begin and
then slowly turn the transformer throttle to the off position and then back on
again to enter the forward phase. Interrupting the power too quickly may
cause the system to re-enter RESET (signaled by two dings of the bell).
Should this happen, wait longer before interrupting the power to enter the
Forward phase.
ProtoSounds® comes with several programmable functions, including
remote Steam Chuffing Volume Adjustment, Separate Bell Button
Operation (pre-programmed at the factory), Whistle In Neutral Operation,
ProtoCoupler™ On/Off Control, Squeaking Brakes and Passenger Station
or Freight Yard Proto-Effects. Each of these features are described in more
detail later. You will notice that when in RESET, your engine will not
respond to the whistle button with a horn blast or continuous bell ringing.
In fact, when in RESET and the whistle button is depressed, only one single
bell chime will be heard each time the whistle button is pressed. If you
don’t want to configure or change your locomotive using any of these
programmable features, simply leave RESET and wait 2.2 seconds before
interrupting the power to put the engine in forward. After you leave
RESET, your engine will operate normally in all the direction states of
forward, neutral and reverse. Remember though, once power is turned off
for more than 3 seconds, the next time power is applied to the track, your
engine will be back in RESET.
WHISTLE OPERATION
Your Big Boy ProtoSound® equipped engine is equipped with a digital
recording of a steam whistle. The whistle sound can be activated anytime
the engine is in forward or reverse by pressing the whistle button on your
transformer. The whistle will continue to blow as long as the whistle button
is depressed. The whistle will not function in RESET and must be
configured through a RESET option to allow the whistle to work when the
engine is in neutral. See page 21 for information on whistle programming
in the Using RESET To Program ProtoSounds® section of this manual.
BELL OPERATION
Your Big Boy ProtoSound® equipped engine is equipped with a digital
recording of an actual steam engine bell. The bell can be turned on or off
with any separate bell button, like the Lionel® Railsounds® No. 5906 Bell

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MTH Big Boy Operating Manual
Button, by simply pushing the button. If you don’t have a separate bell
button, the bell can be controlled through your transformer’s whistle button
whenever the engine is in NEUTRAL. The bell will never ring
continuously in RESET (Remember NEUTRAL is the state between
Forward and Reverse). Once the bell is turned on, it will continue to ring
when the engine is cycled into forward or reverse until you press the bell
button or re-enter NEUTRAL and turn the bell off with the whistle button.
In fact, because of ProtoSounds® state-of-the-art design, the
microprocessor remembers its last command. Therefore, unless you turn
the bell off before you quit running your train, the next time you run the
engine, the bell will come on. No matter whether you come back an hour
later or a year later, the bell will begin chiming once the engine enters one
of the three directional states.
To turn the bell on using the transformer’s whistle button, turn on power to
the track and cycle the engine into NEUTRAL. Turn the throttle to 8 volts
or less (any higher voltage will arm the ProtoCoupler™) and press the
whistle button. The bell should begin chiming. To turn the bell off, press
the whistle button again. If you want to keep the bell on while running the
engine, simply interrupt the power with the transformer throttle or the
transformer directional switch and enter forward or reverse.
PROTO-COUPLER® OPERATION
Your Big Boy ProtoSound® equipped locomotive tender is equipped with
a coil-wound ProtoCoupler® for remote uncoupling action. Because the
ProtoCoupler® is controlled through ProtoSounds® microprocessor, it
doesn’t require an uncoupling track section or modification to your layout
to function. The three simple steps below are required to operate the
coupler.
1. Put your engine in NEUTRAL and turn the throttle all the way up.
2. Press the transformer whistle button to “Arm" the coupler. (You
will hear a “Clank").
3. After arming the
coupler, press the whistle
button again to open the
coupler. H H
Put Engine In Neutral
At Full Power
Press & Release
The Whistle Button Press & Release
The Whistle Button
Listen For The
Ca-Clunk Sound
See The Coupler Open
And Listen For The
Cha-Chusshh Sound

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MTH Big Boy Operating Manual
When the knuckle fires open you will hear the buzzing of the coil
energizing and the sound of the air lines coming apart. It can best be
described as a CHA-CHUSHHH sound. The coupler doesn’t have to be
fired in NEUTRAL. Once the
coupler is armed it can be fired
in Forward, Neutral or Reverse.
However, you may find that the
coupler doesn’t open when
firing the coupler at high
speeds. Reduce the voltage
setting on your transformer if
this occurs and run your engine
at a slower speed before firing
the coupler. If the coupler
continues to open erratically, try
lubricating the knuckle with
light oil as indicated in Fig. 5.
ENHANCED NEUTRAL STEAM SOUNDS
The enhanced Neutral Sounds can be automatically heard whenever the
engine is in neutral. The sounds, which include Steam Pop-Off, Steam
Blow-Down, and Steam Injector sounds occur every 2 to 30 seconds. Each
of the three sequences will play at random intervals to eliminate repetitive
and boring sequences. While the sounds are selected to play randomly by
the microprocessor, there is no guarantee that you won’t hear the same
message repeated twice or more times.
SQUEAKING BRAKE SOUNDS
ProtoSound® equipped engines feature the ability to play the sound of
squeaking brakes whenever your engine slows in speed. There are two
settings for activating the squeaking brake sounds. The default setting
allows the brake sounds to play while the engine is in forward or reverse
and the transformer throttle is lowered from a high setting to a low setting
(14 volts to 8 volts or less). The
second setting requires that a bell
button be used to “arm” the
brake feature and is explained in
more detail in the “Activating
Freight Yard Sounds” section
Lubricate
Coupler
Knuckle
Figure 5: Lubricating The ProtoCouplers
Throttle Down From
High Voltage To Low Listen For The
Squeaking Brake Sounds

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MTH Big Boy Operating Manual
found later in this manual. The sound itself is a stored record on the
ProtoSounds® software chip and will always play the same brake sound for
the same three second length each time the voltage is reduced from high to
low. Some practice may be required to synchronize the playing of the brake
sounds with the movement of the engine. It is not uncommon for the engine
to stop before the brake sound is completed. Operators will find that by
coordinating the movement of the throttle setting from 8 volts to off will
allow the engine to maintain its movement while the brake sounds play.
Note: The brake sounds will not be heard if the transformer throttle is not
set above 14 volts and/or not reduced below 8 volts.
TIPS ON USING THE SQUEAKING BRAKE FEATURE
Because the squeaking brake feature always plays for approximately 3
seconds, it is possible that the brake sounds will play longer or shorter than
what visually seems prototypical. You will find that by practicing with the
brake feature, you can quickly determine how quickly to throttle down and
what speeds and voltage settings give you the most prototypical braking effect.
Typical users will find the feature to be a very realistic way to simulate the
sound of an engine slowing down for curves, crossings or coming to a stop at a
station, side track or switch yard. As mentioned above, you will find that
initially your engine may continue to play the brake sounds once your engine
comes to a stop or that the sounds stop prematurely before the engine comes to
a complete halt. For example, if you simply run the engine and turn the throttle
off quickly, the brake sounds will likely continue playing even though the
engine has come to a complete stop. This annoying effect can be eliminated by
simply practicing with the brake feature. In no time, you will quickly learn
how to “feather" the throttle to keep the engine moving while the brake sounds
play and then turning the throttle off just as the sounds stop. Remember that
once you stop the engine, you should turn the throttle to the off position if you
don’t want to activate the Freight Yard Sounds feature described later in this
manual.
The ProtoSound squeaking brake feature also has the ability to simulate the
squeal of wheel flanges when your train enters a curve at high speeds. The
same brake squealing sound plays, but you don’t need to reduce the transformer
throttle to activate the squealing sounds. To play the squeaking sounds as
wheel flange sounds, set the transformer throttle setting at 14 volts or higher.
As your engine enters a curve (or anywhere on the layout) quickly “flick" your
transformer whistle button about half way. This “flicking" action causes the
transformer to release a short DC signal that ProtoSounds reads as an indicator
to activate the brake sounds. The engine won’t slow down even though the
sounds play. This simulates the wheel flange squeal of a train traveling through
a turn too quickly.
Note: Consistent activation of the wheel flange squealing is determined by the
condition of your transformer’s whistle button rectifier disc. Older rectifier
discs may need to be replaced in order to play squeaking sounds.

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MTH Big Boy Operating Manual
FREIGHT YARD SOUNDS (FYS)
ProtoSounds® comes equipped with operator controlled Freight Yard
Sounds, hereby referred to as FYS. This easy to use feature plays digitally
reproduced freight yard sounds whenever your engine stops on your layout
and is parked in the Neutral position. No additional wires or modifications
are needed on your layout to enjoy these amazing sound effects. The
sounds themselves are randomly generated and randomly “shuffled” on the
ProtoSounds® software chip. This gives the system the ability to produce
different sounds in a different order each time FYS is enabled. These
different sounds are heard each time you cycle the transformer throttle from
ON to OFF to ON in the same manner that you would cycle the throttle to
enter the various states of Forward, Neutral and Reverse. The entire FYS
sequence is designed to simulate the arrival, loading or unloading and
departure of a freight train in a freight yard. Each sequence is described in
more detail in the following sections.
ARMING & ACTIVATING FREIGHT YARD SOUNDS
Your ProtoSound® equipped engine features an operator controlled freight
yard sound set. Once activated, this easy-to-use feature plays the sound of
freight yard activities whenever the operator places the engine in the
Neutralposition.
ARMING THE FREIGHT YARD FEATURE
Before freight yard sounds can be heard, ProtoSounds® must activate the
feature so that the next time the engine enters the Neutral position, the
sounds can play. The Feature can be activated one of two ways.
Option 1: If you are using a separate bell button controller to ring your bell
(like the Lionel® Railsounds® number 5906 bell activation button or a
transformer equipped with a bell button, like the MTH Z-4000), you can
activate the Feature by holding down the bell button for three or more
seconds (it doesn’t
matter if you are in
Forward, Neutral or
Reverse). You will hear
the bell chiming turn on
and if you listen
carefully, you should
Put Engine In Neutral,
Forward or Reverse
Press & Hold
The Railsounds® Bell Button
For 3 Seconds
Listen For The
Start Of The Bell Sound
Listen For The
Whistle Blast Sound
After 3 Seconds

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MTH Big Boy Operating Manual
hear a whistle blast sound effect after three seconds have passed at which
time you can release the bell button. (Note: because the whistle blast
sound may be difficult to hear, we recommend that you count out a full
three seconds before releasing the bell button). The bell will continue to
chime so if you want to turn off the bell chiming, simply press and release
the bell button a second time. If you were in Neutral when you triggered
the Feature, interrupt the throttle to enter either Forward or Reverse to allow
the engine to begin running. (Note: the Feature will only be activated for
the first direction state you enter after leaving the Neutral position. You
cannot interrupt the throttle to enter another direction state and still have
the Feature remain active.) Once your engine begins running, you can
trigger the sounds to begin playing whenever you enter Neutral.
Option 2: If you do not have a separate bell button on your layout (or
transformer), you can still activate the Feature with your transformer
whistle button. To activate the Feature utilizing this method, turn on the
transformer throttle and get your engine into the Neutral position (not
RESET). Once in Neutral, set the transformer throttle at 8 volts or less and
press and hold the whistle button for at least three seconds. You will hear
the bell chiming turn on and if you listen carefully, you should hear a
whistle blast sound effect after three seconds have passed at which time you
can release the whistle button. (Note : because the whistle blast sound may
be difficult to hear, we recommend that you count out a full three seconds
before releasing the whistle button). The bell will continue to chime so if
you want to turn off the bell chiming, simply press and release the whistle
button a second time.
Next, interrupt the throttle
to enter either Forward or
Reverse to allow the engine
to begin running. (Note:
the Feature will only be
activatedforthe first
direction state you enter
after leaving the Neutral position. You cannot interrupt the throttle to enter
another direction state and still have the Feature remain active.) Once
your engine begins running, you can trigger the sounds to begin playing
whenever you enter Neutral.
Put Engine In Neutral
At Low Power
Press & Hold
The Whistle Button
For 3 Seconds
Listen For The
Start Of The Bell Sound
Listen For The
Air Release Sound
After 3 Seconds
H

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MTH Big Boy Operating Manual
ACTIVATING FREIGHT YARD SOUNDS
Once the Feature is activated, FYS will be played the next time the engine
enters the Neutral position. In order for FYS to begin, power must remain
on once the engine enters the Neutral position. At this point, ProtoSounds®
has taken over control of your engine and disabled the bell and whistle
buttons from any further operator actions. In addition, ProtoSounds® has
reconfigured the way the reverse unit functions by disabling the reverse
state during operation of the FYS feature. This forces the engine to leave
your freight yard in the same direction it arrived in. The following operator
controlled “events” control FYS’s actions and sounds.
Event 1 (Forward) While the locomotive is running in forward (or
reverse) FYS is activated by the operator pushing and holding the bell
button down for three or more seconds. The locomotive bell begins
chiming and can be left on or turned off without disabling FYS.
Event 2 (Neural Before Reverse) The operator now interrupts the
transformer throttle to stop the engine and put it into Neutral. If the throttle
setting was at 14 volts or higher , ProtoSounds® will play the sound of
squeaking brake sounds as the engine comes to a halt.
A. Upon stopping of the engine, the operator must immediately turn
the throttle back on to keep the engine in the Neutral position. If the
bell was not turned off after activating FYS, it now turns off
automatically.
Note: Failure to turn the throttle back on within 3 seconds of
leaving the Forward phase will disable
FYS and shutdown ProtoSounds®. The
next time you turn power back on your
engine will be in the RESET position. See
page 6 for more information on RESET.
Put Engine In Neutral
At Low Power

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MTH Big Boy Operating Manual
B. After entering Neutral, ProtoSounds® will immediately play a
whistle blast sound followed approximately 2 seconds later by a man
whistling and a freight car door sliding
open. Immediately following the man’s
whistle, the sound of freight car doors can
be heard opening, followed by the sounds
of freight loading and unloading. At this
point various freight yard sounds can be
heard including the loading/unloading
operation, engine sounds, yardman
“slang”, and additional freight car door
sounds.
Event 3: (Reverse) The operator now interrupts the transformer
throttle again to enter the next reverse unit phase; reverse. In an effort to
enhance realism, FYS has disabled the
reverse phase so that it doesn’t power the
motors causing the engine to move
backward. Upon entering reverse, FYS
confirms to the operator that it has entered
the reverse phase by immediately playing a
highlight sound best described as a
rumbling sound. You may have to go
through the entire FYS sequence several
times before you can clearly identify this
sound. After the rumbling highlight is played, the freight yard sounds heard
in Event 2 continue to play randomly.
Event 4: (Neutral Before Forward) The operator now interrupts the
transformer throttle again to enter the next
reverse unit phase, neutral before forward.
FYS confirms to the operator that it has
entered the neutral before forward phase by
emitting two quick whistle blast sounds.
This is followed approximately two seconds
later by a man whistling and continued
freight yard loading and unloading sounds.
Listen For Air Release Sound
And Yard Man Whistling
Listen For Rumbling
Box Car Door Sound
Interrupt Throttle To
Enter The Next Phase
Listen For 2
Air Release Sounds
Interrupt Throttle To
Enter The Next Phase

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MTH Big Boy Operating Manual
Event 5: (Forward)The operator now interrupts the transformer throttle
again to enter the next reverse unit phase; Forward. FYS confirms to the
operator that it has entered the Forward phase by playing the sound of the
freight car door closing. Within 2 seconds of
the door closing, the locomotive will sound
two short whistle blasts, followed by the bell
beginning to chime. After approximately 8
chimes of the bell, the engine begins moving
in the forward phase with the bell continuing
to ring another 8 chimes before automatically
turning off. Once the bell turns off, the
operator regains control of the transformer
whistle and bell buttons and can ring the bell
or blow the whistle as usual.
Note: When entering the Forward phase of FYS, it is important to set the transformer
throttle at a high enough setting that will allow the engine to begin moving once FYS
automatically activates the motors. Otherwise the engine will just sit still until you increase
the transformer throttle setting on the transformer. However, don’t set the throttle setting too
high or the engine will go racing away faster than you might expect.
Listen For The Sound
Of Box Door Closing
Interrupt Throttle To
Enter The Next Phase

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MTH Big Boy Operating Manual
TIPS ON USING FYS FEATURES
FYS is a unique feature of ProtoSounds™ that is completely controlled by the
operator. You decide how, when or if you want to utilize the feature. By
reviewing the following tips, you should find solutions or suggestions to the
various operating scenarios you might encounter when using FYS.
Tip #1: You can escape the FYS sequence by interrupting the transformer
throttle before the man whistles in Event 2 (neutral before reverse).
Tip #2: You can terminate FYS at anytime by turning the transformer throttle
Off for 15 seconds.
Tip #3: You do not have to be in the Forward phase to utilize FYS. For
example, if you activate the FYS feature while in Reverse and interrupt the
throttle to enter Neutral, you will be entering Neutral Before Forward rather
than Neutral Before Reverse as defined in Event 2 above. Consequently, the
Forward phase will be rendered inactive by ProtoSounds™ instead of the
Reverse phase as explained in Event 3. This will allow your train to leave the
yard in the same reverse direction that it arrived in.
Tip #4: You can utilize FYS even if you are double-heading with another
engine regardless of whether the second engine is equipped with an FYS
programmedProtoSound™module. Ifthesecondengineisn’tequippedwith
FYS, the only thing to remember is that you not turn up the transformer throttle
very high when entering the Reverse phase found in Event 3. If the throttle is
set too high, then the second locomotive will begin vibrating on the track as its
motors will be turning in the reverse state since they cannot be disabled
automatically like FYS equipped engines. If your second engine is equipped
with FYS, you may want to disable it when used in double-headed operations.
To disable FYS, see the section on programming for squeaking brakes and FYS
operation on page 15 of this manual.
Tip #5: It is not necessary for the squeaking brake sounds to be heard to play
the FYS sounds. For example, the brake sounds won’t be heard if the high
voltage setting is below 13 volts when the power is interrupted to enter the
Neutral state.
Tip #6: You can leave any of the event states at any time after entering the
state by simply interrupting the transformer throttle. Any sound effects
programmed to play in that event will simply not occur. The only exception is
Event 2 and Event 5. In Event 2, interrupting the throttle has no effect on FYS
until after the man whistles and the freight car doors have opened. In Event 5,
you cannot interrupt FYS until after the engine begins to move. Interrupting
the throttle before the engine begins to move has no affect on the locomotive’s
operation.

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MTH Big Boy Operating Manual
SELF-RECHARGING BATTERY BACKUP
ProtoSounds® state-of-the-art design includes a self-recharging battery
backup system for improved performance at any speed. The battery ensures
that power to the sound system will remain on during directional changes,
setting RESET options or when traveling over dirty track and switches. The
self-recharging battery backup system is automatically turned on or off
whenever track power is turned on or are off. There no switches needed to
enjoy the benefits of the automatic battery backup system.
ProtoSounds® contains a warning alarm if the battery backup system fails
to automatically disengage when track power is turned off. Should the
backup system fail, you will hear a repeating whistle blast indicating this
has occurred. Should this happen, unplug the battery from the ProtoSound
module (to prevent the battery from being run down) and contact MTH for
instructions on returning the tender for repair.
REPLACING THE PROTOSOUND® BATTERY
The ProtoSound® battery (located in the tender body, is a special NiCad
7-cell, 8.4v battery - NOT the 6-cell, 7.2v battery found in most
convenience stores. The 6-cell NiCad is NOT recommended for use with
ProtoSound® applications. The battery is continually charged from the
track when power is applied and should last for up to five years. In
addition, the NiCad battery is a dry battery and should not leak or cause any
damage to your locomotive during its lifetime.
If you notice that the sounds seem distorted or garbled at low voltages or
become silent when power from the transformer is shut off, the battery may
be going bad. Before replacing the battery, you should put the engine in
NEUTRAL and leave the transformer throttle set at about 12 volts for 15
minutes. This should temporarily recharge the battery. If the garbled or
distorted sounds are reduced, then your battery charge has worn down. You
can give your battery a full charge by leaving the engine ON in the
NEUTRAL position for 6 hours. (Make sure the smoke unit switch is in the
OFF position to prevent harm to the smoke unit wicking).
If you need to replace the battery, replacement ProtoSound® batteries are
available from MTH ProtoSound Electronics at 7020 Columbia Gateway
Drive, Columbia, MD 21046. A standard 9v alkaline battery can be

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MTH Big Boy Operating Manual
substituted as a temporary fix, but since alkaline batteries can’t take a
charge, it will eventually wear down. Regardless, it should give you a week
to a couple of months use while you wait for your replacement
ProtoSound® battery to arrive.
PROTOSOUND® VOLUME ADJUSTMENT
Your ProtoSound® system has two types of volume adjustment. A
manual turn knob on the bottom of the chassis (See Fig. 6 below) allows
you to control all the sounds in the system and a remote control “RESET"
option (Option # 6), allows you to control the volume level of the engine
sounds remotely from the transformer. Turning the volume adjustment
knob clockwise will increase the volume and counterclockwise will lower
the volume of all sounds; bell, whistle, steam chugging sounds, enhanced
neutral sounds, etc. For information on operating the RESET volume
adjustment option, see the section entitled “Programming ProtoSound
RESET Options” on the following pages.
ProtoSound
Volume Adjustment Knob
Figure 6: Adjusting The ProtoSound® Volume

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MTH Big Boy Operating Manual
USING “RESET" TO PROGRAM
PROTOSOUNDS®
As mentioned earlier, there are several programmable options in each
ProtoSound-equipped engine that can be remotely set from any compatible
standard AC transformer equipped with a whistle button. For a list of
compatible transformers, see the chart on page 34. This hands-off approach
gives you unprecedented control of your railroad empire’s motive power
never before seen in model railroading. Each programmable feature can be
accessed whenever your engine is in the RESET state as described earlier
on page 5. By following the instructions below you will find the
programming easy and straight forward.
ENTERING RESET OPTIONS
ProtoSound® is equipped with a few programmable features that are
accessed in the RESET state by moving the transformer throttle up and
down between full voltage and low voltage (6 to 8 volts) without shutting
the transformer off completely. Each time this is done you advance, one
feature at a time, through the available options. An air-release sound is
heard each time the throttle is advanced. In addition, there are special
sounds to tell you what RESET position you are in.
For example, if you want to select Feature 2, you put the engine in
RESET, and move the throttle up and down from full throttle to low two
times. After the second advance, you will hear two “clinks" indicating that
the computer is now in Feature 2. Advance the throttle again and you will
hear three “clinks" for Feature 3. Advance it two more times and you will
hear a “clank" indicating
that you are now in
Feature 5. Advance the
throttle two more times
and you will hear a
“clank" and two “clinks"
indicating Feature 7. ((5
throttle advancements = 1
clank) + (2 throttle
advancements = 2 clinks)). “Clank + “Clink" + “Clink" = Feature 7. You
can advance the throttle as quickly as you like (though you may not hear the
air-release sounds) and the computer will still remember the number of
In RESET Mode
Move The Throttle
Up & Down From
High Voltage To Low
2 Times
Advance The Throttle
Up & Down From
High Voltage To Low
4 More Times
Listen For The
2 Clink Sounds
Listen For 1 Clank
And 1 Clink Sounds

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MTH Big Boy Operating Manual
times the throttle is advanced by playing back the number of “Clinks" and
“Clanks" to confirm the feature you’ve selected.
SETTING THE ENGINE VOLUME
Of all the sounds that come with each ProtoSound® equipped locomotive,
the one most often turned down is that of the engine volume because it is
the one sound normally heard whenever the engine is running and is what
usually can become tiresome to the ear over prolonged running sessions.
The volume adjustment is controlled through RESET Feature 6.
To access the feature, advance the transformer throttle to put the engine in
RESET. Move the throttle up and down, as described on page 5, 6 times.
After you hear the “clank" and “clink" indicating that you are in Feature 6,
press the whistle button to select the engine volume level you desire.
Pushing the whistle button once will give you full volume, which is the
factory setting. Pushing the whistle button a second time will give you 50%
volume, pushing it a third time will give you 25% volume and pushing it a
fourth time will give you no sound. The microprocessor will immediately
play the sound level each time the whistle button is pushed so that you can
decide if it is acceptable. You can recycle through the four choices by
simply continuing to
press the whistle button.
Once you have decided
on the appropriate
volume level, turn the
transformer throttle off
and on again or press
the transformer direction switch to lock in your selection. The volume
adjustment will remain set at the level you have chosen until you change it
again. Regardless of the engine volume setting, the horn, bell, compressor
and neutral sounds will function normally. In fact because only the engine
volume is affected by selections in Feature 6, when you select 0 volume,
you can still hear the horn, bell and neutral sounds when the engine is
running or in neutral.
In RESET Mode
Move The Throttle
Up & Down From
High Voltage To Low
6 Times
Listen For 1 Clank
And 1 Clink Sounds
Push The Whistle Button
Until You Reach The
Setting You Desire
Interrupt The Throttle
To“Lock-In”
The Volume Setting
H

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MTH Big Boy Operating Manual
PROGRAMMING FOR A SEPARATE BELL BUTTON
CONTROLLER
To operate ProtoSounds® with
a separate bell button controller,
like the Lionel® No. 5906 bell
button, you will need to wire up
the controller to your
transformer and track as shown
in Fig. 7. Once the button is
wired, ProtoSounds® comes
preprogrammed to allow you to
operate the bell by simply
pushing the bell button once.
To turn the bell off, push the
button again. If the bell doesn’t function when you press the button, you
may need to re-program ProtoSounds® to operate with a separate bell
button controller. To do this enter RESET and go to Feature 20. (See the
section Using RESET To Program ProtoSounds®on page 18.) Once in
Feature 20, press the whistle button and wait for the module to sound a bell
ding(s). Continue
pushing the whistle
button until the module
plays back two dings
(signifying that the
module has been
programmed for a bell
button). Simply turn the
throttle off and then on again to “Lock-In" the new setting. To reset the
computer to its original factory (default) setting (separate bell button
operation), repeat the above procedure but keep pushing the whistle button
until the computer only responds with one bell ding.
PROGRAMMING FOR SQUEAKING BRAKE
OPERATION
ProtoSounds® can be programmed for squeaking brake operation in three
different manners; (1)Squeaking brakes can be activated by bell button
control, (2)they can be programmed for continuous operation subject to
throttle changes or (3)they can be programmed to be turned off. The default
setting is (2) Squeaking brakes are in continuous operation as described on
page 8. To change the default setting, enter RESET and go to Feature 45.
Common
RED Wire
BLACKWire
U
AU BU CU D
Figure 7: Wiring Up A Bell Button
In RESET Mode
MoveTheThrottle
Up & Down From
High Voltage To Low
20Times
Listen For 5 Clank
And 0 Clink Sounds
Push The Whistle Button
Until You Hear 2 Dings
Interrupt The Throttle
To “Lock-In”
The Bell Button Setting
H