Royal Vendors Merlin IV Building instructions

Royal Vendors, Inc.
Service and Parts Manual
Merlin IV
R
Manufactured by
Telephone [phone] • Fax [phone] • [email protected] • [email protected] • www.royalvendors.com
Royal Vendors, Inc.
426 Industrial Boulevard
Kearneysville WV 25430-2776 USA

Royal Vendors, Inc. • 426 Industrial Boulevard • Kearneysville WV 25430-2776 • USA
Customer Service: [phone] or Toll Free (in North America only) 1 800 931 9214 • Fax [phone]
E-mail: [email protected]
[email protected]
Web page: www.royalvendors.com

Table of Contents
Safety Segment.................................................................................................................... 5
1. General Information....................................................................................................... 7
Introduction to Merlin IV ...............................................................................................................................................7
Merlin IV Features..........................................................................................................................................................7
Vender Identification.......................................................................................................................................................8
Voltage Requirements.....................................................................................................................................................9
2. Vender Component Explanation................................................................................. 10
Vender Control Board (including pinouts) ...................................................................................................................10
Low Voltage Transformer.............................................................................................................................................15
Delivery Chute Sensor..................................................................................................................................................16
Refrigeration System....................................................................................................................................................17
Ballast...........................................................................................................................................................................19
Credit Peripherals .........................................................................................................................................................19
3. Vender Programming................................................................................................... 20
The Necessity Of Correct Programming ......................................................................................................................20
Precautions To Take When Working With The Control Board.....................................................................................20
Introduction To Programming ......................................................................................................................................20
Menu Levels .................................................................................................................................................................21
INTERNAL (Service) MENU......................................................................................................................................22
CASH (cash counter) Mode .....................................................................................................................................22
SALE (sale counter) Mode ......................................................................................................................................22
CArd (card counter) Mode......................................................................................................................................23
to4n (token counter) Mode....................................................................................................................................23
FrEE (free vend accounting) Mode ........................................................................................................................23
Eror (errors) Mode................................................................................................................................................24
tESt (column test vend) Mode ..............................................................................................................................24
PriC(selection price) Mode...................................................................................................................................24
StoS (space to sales) Mode....................................................................................................................................25
SdEP (set vending depth ) Mode............................................................................................................................26
Con (configurations) Mode.....................................................................................................................................26
rtn (return to sales) Mode.....................................................................................................................................27
OPTIONAL MENU (If Con 2 is set “1”).....................................................................................................................27
ECO (exact change mode) .......................................................................................................................................27
CPO (coin payout) Mode.........................................................................................................................................27
tUFL (coin tube fill) Mode .....................................................................................................................................28
dSAL (discounted sale counter) Mode....................................................................................................................28
diFc (discounted differential cash counter) Mode.................................................................................................28
SdiS (discounted selection price) Mode................................................................................................................29
StCL (set timer controlled selections) Mode..........................................................................................................29
tinE (time and timer settings) Mode.....................................................................................................................30
FriG (refrigeration parameters) Mode...................................................................................................................32
PAS (External Menu password setting) Mode........................................................................................................35
LAnG (international language setting) Mode..........................................................................................................35
rtn (return to sales) Mode.....................................................................................................................................35
External Menu (accessible while in the “greeting” mode)...........................................................................................36
SALE (sale counter) Mode ......................................................................................................................................36
rtn (return to sales) Mode.....................................................................................................................................36
Eror (errors) Mode................................................................................................................................................36

4. Vend Cycle.................................................................................................................... 37
Stand by Condition.......................................................................................................................................................37
Establishing Credit........................................................................................................................................................37
Valid Selection..............................................................................................................................................................37
Vend Sequence..............................................................................................................................................................37
Product Delivery...........................................................................................................................................................37
Column Sequencing......................................................................................................................................................37
Sold Out........................................................................................................................................................................37
Resetting Sold Out Selections ......................................................................................................................................37
5. Vender Maintenance .................................................................................................... 38
General Maintenance....................................................................................................................................................38
Using The Vender’s Error Code System.......................................................................................................................39
Error Codes...................................................................................................................................................................39
Troubleshooting............................................................................................................................................................40
Refrigeration Troubleshooting Flow Chart...................................................................................................................46
6. Training Guide..............................................................................................................47
7. Exploded Views and Part Numbers............................................................................ 51
Control Board and Wiring ............................................................................................................................................52
Port Assembly...............................................................................................................................................................54
Inner Door Assembly....................................................................................................................................................56
Main Door Hinge, Lifter, & T-handle Assemblies........................................................................................................58
Refrigeration System Assembly ...................................................................................................................................60
Evaporator Fan Motor Assembly..................................................................................................................................62
Airflow Vend Mechanism Assembly (200422XX00001 and after)..............................................................................64
Vend Mechanism Assembly (before 200422XX00001)...............................................................................................66
Miscellaneous Assemblies............................................................................................................................................68
Door Assembly, Front...................................................................................................................................................70
Door Assembly, Rear....................................................................................................................................................72
Select Panel Assembly, Rear.........................................................................................................................................74
RVMC/RVCD Vandal Resistant Door (CDC) Front ....................................................................................................76
RVMC/RVCD Vandal Resistant Door (CDC) Rear......................................................................................................78
RVMC/RVCD Center Door Changer Vault..................................................................................................................80
Port Assembly, Dr Pepper Vision 4 ..............................................................................................................................82
Door Assembly Front, Dr Pepper Vision 4...................................................................................................................84
Door Assembly Rear, Dr Pepper Vision 4....................................................................................................................86
Coin Insert Assembly Front, Dr Pepper Vision 4.........................................................................................................88
CI Rear and Button Panel Assembly, Dr Pepper Vision 4............................................................................................90
Changer Vault Assembly, Dr Pepper Vision 4..............................................................................................................92
Flat Horizontal Display, Door Front.............................................................................................................................94
Flat Horizontal Display, Door Rear..............................................................................................................................96
Flat Horizontal Display, Select Panel..........................................................................................................................98
Programming Flowcharts............................................................................................... 100
Schematics....................................................................................................................... 102
Table of Contents (continued)

5
Merlin IV Service and Parts Manual
Safety Segment
ROYAL VENDORS’ COMMITMENT TO
SAFETY
Royal Vendors is committed to safety with all of our
product designs. We are committed to notifying the user
of a possible danger involving the improper handling
or maintenance of our venders. The servicing of any
electrical or mechanical device involves potential dangers,
both to those servicing the equipment and to users of the
equipment. These dangers can occur because of improper
maintenance or usage. The purpose of this safety segment
is to alert everyone servicing Royal equipment of
potentially dangerous areas, and to provide basic safety
guidelines for proper upkeep.
The service manual contains various warnings that should
be carefully read to minimize the risk of personal injury.
This manual also contains service information to ensure
that proper methods are followed to avoid damaging
the vender or making it unsafe. It is also important to
understand these warnings provide general guidance only.
Royal could not possibly know, evaluate, or advise of all
of the conceivable ways in which service might be done.
Consequently, Royal cannot predict all of the possible
dangerous results. These outlined safety precautions
are the basis for an effective safety program. Use these
safety measures, along with the service bulletins, helpful
hints and product specification sheets, when installing or
servicing Royal equipment.
We recommend that persons servicing our equipment
maintain a similar commitment to safety. Only personnel
properly trained should have access to the interior of
the vender. This will minimize the potential dangers
that are inherent in electrical and mechanical devices.
Royal has no control over the vender once it leaves the
premises. It is the owner or lessor’s responsibility to
maintain the vender in a safe condition. See installation
insert located in the coin box of a new vender for proper
installation procedures and refer to the service manual
for recommended maintenance procedures. If you have
any questions, please contact the Technical Services
Department at 1 800 931 9214 (outside North America,
dial [phone]).
SAFETY REGULATIONS
· Read the safety segment before installation or
service.
· Test for proper grounding before installing to reduce
the risk of electrical shock and fire.
· Turn off or disconnect power cord from wall outlet
before servicing.
· Only fully trained service technicians should service
vender when vender has power.
· Remove any product before moving a vender.
· Use appropriate equipment when moving a vender.
· Always wear eye protection, and protect your hands,
face, and body when working near the refrigeration
system.
· Use only authorized replacement parts.
· Be aware of inherent dangers in rocking or tipping a
vender.
SECTION I: ELECTRICAL HAZARDS
GENERAL ADVICE
Careless or improper handling of electrical circuits can
result in injury or death. Anyone installing, repairing,
loading, opening, or otherwise servicing a vender should
be aware of this precaution. Apply all of the normal
precautions when handling electrical circuits, such as:
· Refrigeration servicing to be performed by qualified
personnel only.
· Unplug the vender before servicing.
· Replace electrical cords if there is any evidence of
fraying or other damage.
· Keep all protective covers and ground wires in place.
· Plug equipment into outlets that are properly
grounded and polarized (where applicable), and
protected with fuses or circuit breakers of the correct
size.
· All electrical connections must be dry and free of
moisture before applying power.
WARNING: ALWAYS TEST TO VERIFY PROPER
GROUNDING PRIOR TO INSTALLATION IN
ORDER TO REDUCE THE RISK OF ELECTRICAL
SHOCK AND FIRE

6Merlin IV Service and Parts Manual
SECTION II: ELECTRICAL
HAZARDS
A. Servicing with Power Off
For maximum safety, unplug the power cord from the
wall outlet before opening the vender door. This will
remove power from the equipment and avoid electrical
hazards. Service personnel should remain aware of
possible hazards from hot components although electrical
power is off.
B. Servicing with Power On
Some service situations may require access with power
on. Only fully qualified service technicians should
perform power-on servicing. Particular caution is required
in servicing assemblies that combine electrical power
and mechanical movement. Sudden movement (to escape
mechanical action) can result in contact with live circuits
and vice versa. It is therefore important to maintain
maximum clearances from both moving parts and live
circuits when servicing.
WARNINGS:
1. ONLY FULLY TRAINED PERSONNEL SHOULD
ACCOMPLISH “POWER-ON” SERVICING. SUCH
SERVICE BY UNQUALIFIED INDIVIDUALS CAN
BE DANGEROUS.
2. LIGHTING CIRCUITS CAN BE HAZARDOUS.
ALWAYS DISCONNECT VENDER FROM THE
WALL OUTLET BEFORE REPLACING A BULB OR
SERVICING THE VENDER IN THATAREA.
3. NEVER USE A HOSE, PRESSURE WASHER
OR ANY CLEANING METHOD THAT COULD
WET ELECTRICAL COMPONENTS. SEE
CLEANING SECTION OF MANUAL FOR
SUGGESTED CLEANING METHODS. IF WATER
CONTAMINATION OF ELECTRICAL COMPONENTS
IS SUSPECTED, USE QUALIFIED ELECTRICAL
TESTING EQUIPMENT AND TEST METHODS
TOASSURE THAT VENDER IS NOT A HAZARD
BEFORE APPLYING POWER FOR ANY REASON.
Safety Segment

7
Merlin IV Service and Parts Manual
Section 1. General Information
1
st
Level 2
nd
Level 3
rd
Level
enter enter
home
home
up down
down
up down
up
Figure 1.1. Merlin IV menu levels.
General Information
INTRODUCTION TO MERLIN IV
The MERLIN IV can and bottle vender is capable of
vending most packages. It uses an electronic control
board to manage vending operations. This control board
must be programmed correctly for the vender to operate
properly. Through the vender’s electronic control board,
you will find better space to sales allocations which will
increase profits through fewer sold out selections and less
loading frequency.
Through MERLIN IV’s flexibility, you will profit by
using the Multi-Pricing and Space to Sales features. As
you will see later in the manual, there are other features,
such as the ability to control vending by using a “built
in” timer or by using an optional on/off key switch. Like
most electronic equipment, the control board has the
ability to control most items in the vending machine. It
manages the operation of the refrigeration system, and
even the lighting system, with an optional kit. MERLIN
IV utilizes high torque 24-volt DC vend motors. Testing
has proven these vend motors to be very strong and
reliable.
MERLIN IV’s programming is done “Menu Style” with
the menus consisting of “Main Items” and “Sub-Items.”
Figure 1.1 is a good example of how the menu system
works.
“Cash” is the first menu after pressing the mode button on
the control board. You can only access menu items from
the menu you are in. Just as the “ENTER” button takes
you into each level, the “HOME” button takes you back
to previous menu levels each time you press it. The menu
system is explained in greater detail in Section 4. Vender
Programming: Menu Levels.
MERLIN IV FEATURES
• Field proven, reliable impact delivery sensor detects
the vend to cancel vend cycle.
• Patented learning mode for quick vending.
• A “direct drive” DC vend motor in each column
drives each column’s vend rotor.
• No vend mechanism adjustments are necessary to
change from 12 oz. cans to 16 oz. or 20 oz. bottles.
All that is needed is to change the depth setting in
the programming and product retainers / rear spacers
adjustments.
• User-friendly menu style programming.
• Hand Held Computer (HHC) programming and data
retrieval.
• Real time clock / calendar to control “built-in” timer
(can display time on LED).
• MERLIN IV supports Multi-Drop Bus coin
mechanisms, bill validators, and card readers.
• Allows programmable space to sales: custom or
factory settings.
• Capable of setting full escrow to vend (even if a
column jams).
• External menu allows access to sales (vend) counts
and error information.
• Both total (historical) and individual (resettable) vend
and cash counters.
• MERLIN IV can display the sale (vend) and cash
totals (historical) on the LED upon opening the
vender’s main door for easy access.

8Merlin IV Service and Parts Manual
VENDER IDENTIFICATION
Your MERLIN IV vending machine can be easily
identified by taking note of the following three items:
1. Vender serial plate - mounted on the exterior left side
of the vender door,
2. Refrigeration serial plate - mounted on the “kick
plate” of the refrigeration unit, and
3. Control chip revision number - mounted on the right
side of the control board.
VENDER SERIAL PLATE
Note: There are two styles of serial plates issued. See
figures 1.2 and 1.3.
VENDER SERIAL PLATE - The vender’s main serial
plate (shown in figures 1.2 and 1.3) is located on the
exterior left side of the vender’s main door and has the
following information:
- Vender model number
- Vender serial number
- Amps required by vender
- Unit charge of R134a
- Refrigeration design pressures
The vender’s model number contains two important
pieces of information: the machine type, such as RVCDE
(Royal Vendors Cold Drink Electronic); and the vender
model number, such as 650-10 (capacity of 650 twelve-
ounce cans / 10 selections).
Section 1. General Information
How to read the newer-style serial number (figure 1.2):
• The first four numbers represent the year the vender
was produced.
• The fifth and sixth numbers represent the week within
the year the vender was produced.
• The first letter represents the style of vender.
• The second letter represents the location the vender
was built.
• The last five numbers represent the model built with
in that week.
How to read the older-style serial number (figure 1.3):
The older-style serial number contains three important
pieces of information: the production run number, such
as 1466; a date code, such as BK; and the vender number
from within the run, such as 01489. The first letter of the
date code (B) represents the quarter of the year that the
vender was produced:
A = Jan., Feb., Mar. B = Apr., May, Jun.
C = Jul., Aug., Sept. D = Oct., Nov., Dec.
The second letter of the date code (K) represents the year
that the vender was produced:
A = 1988 B = 1989 C = 1990 D = 1991
E = 1992 F = 1993 G = 1994 H = 1995
I = 1996 J = 1997 K = 1998 L = 1999
M = 2000 N = 2001
Figure 1.2. Current vender serial plate. Figure 1.3. Older style vender serial plate.

9
Merlin IV Service and Parts Manual
Section 1. General Information
REFRIGERATION SERIAL PLATE
The refrigeration serial plate is located at the bottom
of the vender’s cabinet in front of the condenser coil. It
is mounted to the refrigeration unit kick plate. It looks
similar to the serial plate shown in Figure 1.2, with
the exception that the model number specified is the
refrigeration unit model (as shown below). There is
currently one model in use:
Model Compressor Size Usage
8000W Super 1/3 All MERLIN IV
Horsepower Venders
CONTROL CHIP VERSION NUMBER
The control chip version number is printed on a white
decal located to the to top right of the main chip of the
control board. This number is extremely important when
calling for service / programming help, or for matching a
replacement control board. See figure 2.2.
IMPORTANT NOTE: To serve you better, we ask you
have the following items available before contacting your
Royal Vendors service representative:
A. Your company’s name
B. Your company’s telephone number
C. Your first and last name
D. The vender’s model number
E. The vender’s serial number
F. The vender’s control board revision number (if
concerning a board or programming)
It is also very important to have all of the information
about your problem available when you call.
VOLTAGE REQUIREMENTS
The vender is designed to operate at a voltage of 115
volts, 60 hertz. It requires a minimum of 15 amp service.
The service outlet voltage must not exceed 129 VAC
or fall below 103 VAC. The vender has a three prong,
three wire, grounding cord. The vender must be plugged
into a grounded electrical outlet to protect the customer
from an electrical shock. If you are not sure your outlet
is properly grounded, have it checked by a qualified
electrician.
When you plug in the vender, you should observe the
following:
1. The fluorescent lights displaying the vender sign will
illuminate.
2. The refrigeration compressor will start to run after
approximately 5-7 minutes (with the door closed).
3. The LED display will light.
VENDER POWER CORD NOTE
Extension cords are not recommended, unless they are
authorized before use by a certified electrician.

10 Merlin IV Service and Parts Manual
Section 2. Vender Component Explanation
Vender Component
Explanation
VENDER CONTROL BOARD (including
pinouts)
Your MERLIN IV vender is equipped with a main control
board which is responsible for most vender operations.
In most venders (non-CDC), it is located in the upper
section of the select panel inside the vender’s main door.
The control board is protected by a cover. Removing this
cover will expose the control board in its entirety, along
with all of the control board’s wiring connections.
IDENTIFICATION: The MERLIN IV control board can
easily be identified by noting the identification number
printed on a small white decal on the control board’s
EEPROM chip. The control board’s identification number
is a necessity when ordering parts for your vender and
when contacting a Royal Vendors service representative.
The control board identification decal is shown in “Vender
Identification” of Section 1.
OPERATION REQUIREMENTS: The control board
requires approximately 24 volts AC from the low voltage
transformer (described later in this section). This will
allow the control board to function and to supply power to
all the vender’s components listed below.
OPERATION: Upon receiving the appropriate voltage
from the transformer, the control board will issue
information to some components, receive information
from some components, and communicate both ways with
some components.
• The control board issues instructions (and / or
voltage) to:
LED display
Vend motor (only when vend motor is to run)
Refrigeration relay (for use with electronic
refrigeration control)
• The control board receives information (and / or
voltage) from:
Select switches (logic level)
Door switch (logic level)
Delivery chute sensor
Temperature sensor (for use with electronic
refrigeration control)
• The control board communicates both ways with:
Coin mechanism
Bill validator (optional)
Debit card reader (optional)
Hand Held Computer (optional)
CONTROL BOARD PINOUTS: The MERLIN IV
control board has several electrical pinouts, a set-up mode
button, a delivery sensor adjustment trimpot, a delivery
sensor adjustment indicator lamp, and various other
electronic components (all of which have designated
position codes). The following section outlines all the
control board’s pinouts by showing for each:
• The pinout position code as found on the control
board (example: P15);
• The name / purpose of the pinout (example: 24-volt
power connection);
• A paragraph describing in detail the pinout’s purpose
and its function; and
• A table describing the pin number, wire number, and
function of each position.
The word key refers to the small plastic insert plugged
into a position of the connector. The purpose of the key
is to prevent connecting the harnessing backwards or
upside-down. The “keyed position” is a blank position
within the pinout (no pin) in which a key is inserted.
Some pinouts may have several blank positions with a key
plugged into one or more of the positions. You can use
the key to determine which end of the pinout is pin 1.

11
Merlin IV Service and Parts Manual
Section 2. Vender Component Explanation
MERLIN IV CONTROL BOARD
Standard LED Display Interface (Position P1): The four
(4) wire harnesses connecting to this pinout travel from
the vender’s LED to the control board. It allows the
control board to send power to and communicate with
the LED. If this harness is cut or disconnected, the LED
will go blank. If this harness is pinched, you may see
“broken segments” on the LED with various segments of
the display lit.
PIN WIRE FUNCTION
NUMBER COLOR
1 YELLOW 5 VDC POWER
2 GREEN DISPLAY CLOCK
3 BROWN DISPLAY DATA
4 RED DISPLAY 5 VDC
RETURN TO COMMON
Control Board
EEPROM Chip
White Decal
(software revision)
P1 DISPLAY P10 DEX 2 P11 DEX 1
P7 SELECTION SWITCHES
MODE
P9 OPTION SWITCHES
P4 Drop Sensor
P3
P15
P8
P14
P12
Pins
Figure 2.1. Merlin IV control board layout and EEPROM
location.

12 Merlin IV Service and Parts Manual
Multi-Drop Bus (Position P3): The five (5) wire serial
harness connecting to this pinout provides power and
communications to and from the control board for the
coin mechanism, the optional 24-volt bill validator, and
/ or the optional debit card reader. If this harness is cut,
pinched, or disconnected, you will noticeably lose power
to the coin mechanism.
PIN WIRE FUNCTION
NUMBER COLOR
1 WHITE MDB 35 VOLTS DC
UNREGULATED
2 BROWN MDB 35 VOLTS DC
RETURN TO
COMMON
3 KEY KEY
4 BLACK VMC RECEIVE/
MDB TRANSMIT
5 RED VMC TRANSMIT/
MDB RECEIVE
6 GREEN VMC/MDB
COMMON
7 BLUE NOT USED
Delivery Sensor (Position P4): The two (2) wire harness
connecting to this pinout is a grey, shielded cable harness.
It should never be cut, pinched, or spliced. This harness
is formed into the impact sensor (mounted beneath the
center of the delivery chute). It travels through the
bottom of the vender’s main door to the control board.
PIN WIRE FUNCTION
NUMBER COLOR
1 - NOT USED
2 - VMC COMMON (2.5DC)
RETURN TO GROUND
3 RED DROP SENSOR
OUTPUT #1
4 BLACK DROP SENSOR
OUTPUT #2
5 - VMC COMMON
RETURN TO GROUND
6 - NOT USED
Selection Switches (Position P7): The wiring harness
connecting to this pinout carries a logic level (ground)
signal from pin 11 of the control board to the common
position of each select switch. Upon activation, the select
switch will allow the logic level signal to travel back
to the control board. This will tell the control board a
particular switch is activated.
PIN WIRE FUNCTION
NUMBER COLOR
1 WHITE SEL SWITCH #9
2 YELLOW SEL SWITCH #8
3 ORANGE SEL SWITCH #7
4 GREEN SEL SWITCH #6
5 BLUE SEL SWITCH #5
6 BROWN SEL SWITCH #4
7 PURPLE SEL SWITCH #3
8 GREY SEL SWITCH #2
9 BLACK SEL SWITCH #1
10 KEY KEY
11 RED COMMON
12 - SEL SWITCH #12
13 - SEL SWITCH #11
14 PINK SEL SWITCH #10
Vend Motors (Position P8): The fourteen (14) wire
harness connecting to this pinout provides common power
from the control board to each vend motor. There is one
wire in this harness for each vend motor to provide each
motor with 24 volts DC, when a selection is made. Be
sure that this harness is properly grounded.
PIN WIRE FUNCTION
NUMBER COLOR
1 GREEN VEND MOTOR #1
2 RED VEND MOTOR #2
3 YELLOW VEND MOTOR #3
4 ORANGE VEND MOTOR #4
5 BROWN VEND MOTOR #5
6 BLUE VEND MOTOR #6
7 GRN / WHITE VEND MOTOR #7
8 RED / WHITE VEND MOTOR #8
9 YLW / WHITE VEND MOTOR #9
10 KEY PP
11 ORNG / WHITE VEND MOTOR #10
12 BR / WHITE VEND MOTOR #11
13 BLUE / WHITE VEND MOTOR #12
14 BLACK VEND MOTOR
COMMON (Source)
15 GRN / YLW GROUND
Section 2. Vender Component Explanation

13
Merlin IV Service and Parts Manual
Features Connection (Position P9): The wiring harness
connecting to this pinout travels from the vender’s door
switch through the bottom of the vender’s main door
and to the control board. Pinout P9 is also used for the
optional “free vend” and “no vend” key switch kits.
PIN WIRE FUNCTION
NUMBER COLOR
1 WHITE FEATURE PLUG/
SWITCH COMMON
2 - KEY
3 (OPTIONAL) FREE VEND
SWITCH INPUT
4 (OPTIONAL) NO VEND
(VEND DISABLE)
INPUT
5 (OPTIONAL) OPTION SWITCH
INPUT
6 PURPLE DOOR SWITCH
INPUT
DEX UCS Connection (Position P10): The three (3) wire
harness connecting to this pinout comes from the Hand
Held Computer jack, located inside the vender’s main
door (near the control board). The Hand Held Computer
(HHC) plugs into this jack to read and write information
from the vender’s control board. If the HHC is not
operating properly, check this harness for bad connections
at the solder joints. Also check to ensure the insulator is
not cracked from over tightening.
PIN WIRE FUNCTION
NUMBER COLOR
1 RED VMC TRANSMIT/DEX
RECEIVE DATA (TIP)
2 - KEY
3 WHITE VMC RECEIVE / DEX
TRANSMIT DATA
(RING)
4 GREEN DEX COMMON
DEX UCS Connection (Position P11): The three (3) wire
harness connecting to this pinout comes from the external
Hand Held Computer jack located on top of the welded
port assembly. The Hand Held Computer plugs directly
into this jack while the vender’s main door is closed
to read information from the vender’s control board.
Information cannot be written to the vender’s control
board unless the vender’s door switch is in the “door
open” position. If the HHC does not operate properly,
check the harness for bad connections at the solder joints.
Also check to ensure the insulator at the jack is not
cracked from over tightening.
PIN WIRE FUNCTION
NUMBER COLOR
1 RED TRANSMIT / DEX
RECEIVE DATA (TIP)
2 - KEY
3 WHITE RECEIVE / DEX
TRANSMIT DATA
(RING)
4 GREEN DEX COMMON
Primary Temperature Sensor (Position P12): The
wiring harness connecting to this pinout travels from the
temperature sensor to the control board. The temperature
sensor is mounted on the rear tank above the evaporator
fan. This harness is molded into the temperature sensor
and should never be cut, pinched, or spliced together
if cut. If the harness is cut, pinched, or improperly
grounded, the sensor may give the control board false
temperature readings. Refrigeration activity is based on
the signal reported to the control board from this sensor
(pin 2).
PIN WIRE FUNCTION
NUMBER COLOR
1 BLACK TEMP. SENSOR 5 VOLT
DC SUPPLY
2 KEY KEY
3 WHITE TEMP. SENSOR SIGNAL
4 RED TEMP. SENSOR 5 VOLT
RETURN TO COMMON
Section 2. Vender Component Explanation

14 Merlin IV Service and Parts Manual
Auxiliary Temperature Sensor (Position P13): This pinout
may be available in the future, but as of this service
manual printing it is not available.
PIN WIRE FUNCTION
NUMBER COLOR
1 - -
2 - -
3 - KEY
4 - -
Environmental Controls (Position P14): The wiring
harness connecting this pinout powers the refrigeration
relay (to power the refrigeration unit). It is also
responsible for powering any optional relays, such as
the heater relay, evaporator fan relay, illumination (sign
lighting) relay, and a 24-volt DC counter. It powers each
relay and counter by providing a constant 24 volts DC to
each relay from pin 1. Upon activation, the control board
will remain neutral for each relay, or counter, from either
pins 2, 3, 4, 6 or 7.
PIN WIRE FUNCTION
NUMBER COLOR
1 2X1 24 VDC
2 2X2 HEATER RELAY
3 2X3 COMPRESSOR RELAY
4 2X4 FAN RELAY
5 KEY FAN RELAY OUT
6 2X6 FLUORESCENT LIGHT
RELAY
7 - IMPULSE COUNTER
8 - 24 VDC
24 VoltAC Power In (Position P15): The two (2) wire
harness connecting this pinout come from the low-voltage
transformer. It is imperative the correct harness be
connected to this pinout. If this harness is not connected
(or if power is lost to this connection), the vender will
noticeably lose all functions (except main door lighting),
including power to the LED display. The coin mechanism
will not accept coins. The compressor and condenser fan
motor also will not run. With this connector, the wire
harness can be in either position and the control board
will not be affected.
PIN WIRE FUNCTION
NUMBER COLOR
1 - 24 VOLTAC
2 - NEUTRAL
Section 2. Vender Component Explanation

15
Merlin IV Service and Parts Manual
LOW VOLTAGE TRANSFORMER
(Run 1476 and after will have a fuse between the
transformer and the control board)
The MERLIN IV vender uses a low-voltage (75 VA)
transformer which reduces 115 volts AC (conventional
voltage) to 24 volts AC, to power the vender’s control
board. The transformer is a major contributor to the
vender’s operation. Without the transformer, the control
board cannot function.
LOCATION OF TRANSFORMER: In a CDC (Center
Door Changer) vender, the transformer is located below
the control board. The fuse is fastened to the changer plug
bracket. In a non-CDC vender, the transformer and fuse
are located at the top of the main door.
OPERATION: The transformer has a three (3) amp
external fuse on a secondary circuit to protect the control
board and the coin mechanism. If the transformer
fuse blows, you will lose power to the control board,
noticeably cutting power to the LED display, and also
cutting power to the coin mechanism and bill validator. If
you have a problem similar to this, follow the procedures
listed below.
OPERATION REQUIREMENTS: The transformer
operates by receiving 110 volts AC from the Vender
(black and red wires). It transforms the 110 volts AC into
24 volts AC which is what the Control Board requires for
its operation.
CHECK THE TRANSFORMER AND FUSE: If upon
arriving at a vender, the LED display is not lit and
the coin changer does not take coins or pay out coins,
make sure the vender is plugged in. Next, check the
transformer’s external fuse for visual damage. Check for
continuity across the fuse with a voltage meter or similar
device. If defective, replace the external fuse.
Note: Merlin IV venders made before run 1476 use an
internal fuse in the transformer.
1. Check the power going into the transformer at the
connected red and black wires. It should register 115
volts AC. If not, check all wiring leading up to this
point from the bottom of the vender’s main door. The
transformer may not be the problem. There may be a
broken wire or a bad connection.
2. If 115 volts is registered during Step 1, measure
voltage at the other end of the transformer. The
two-pin connector at the control board connected to
position P15 should register approximately 24 volts
AC at this end of the harness. If so, check the control
board; the transformer is good.
3. If 115 volts is registered during Step 1 and 24 volts
AC is not registered during Step 2, the vender has a
bad transformer. Unplug the vender and transformer
connections at the transformer (115-volt side).
Unplug the transformer from the control board and
remove it from the vender’s main door by locating
the side of the transformer that has two built-in wires
going into the plastic housing.
Section 2. Vender Component Explanation

16 Merlin IV Service and Parts Manual
DELIVERY CHUTE SENSOR
ADJUSTMENT: Located below the sensor connector
is the sensor adjustment trimpot, which includes an
adjustment screw. The trimpot is used to adjust and fine-
tune the sensor. It is capable of turning both clockwise
and counterclockwise. Located directly above the
trimpot is the sensor adjustment LED indicator light. The
indicator light is mainly used to aid in adjusting the sensor
but can also be used to test its operation during product
impact.
1. Turn the adjustment screw clockwise until the
indicator light comes on.
2. Turn the screw counterclockwise until the light just
goes out.
3. Continue to turn the screw counterclockwise one
turn. Note: Slight adjustments may be needed outside
the factory set one turn. Turning the adjustment
screw clockwise makes the sensor more sensitive and
counterclockwise makes it less sensitive. Test vend
after every 1/4 turn.
For multiple-vending from all columns, make sure the
sensor is adjusted to the factory specifications as listed
above. Next, turn the adjustment screw clockwise 1/4
turn to increase sensitivity. Test vend columns 7 and 12,
and watch the light on the board for a good on and off
flash. If still multiple-vending, turn the adjustment screw
an additional 1/4 turn clockwise until proper adjustment
is made.
For dry-vending from all columns, make sure the sensor
is adjusted to the factory specifications as listed above.
Next, turn the adjustment screw counterclockwise 1/4 turn
to decrease sensitivity. Test vend all columns. If still dry-
vending, turn the adjustment screw an additional 1/4 turn
counterclockwise until proper adjustment is made.
TESTING THE DELIVERY CHUTE SENSOR: Make
sure the vender is plugged in and the controller has power
(the LED display on the front of the vender will be lit
and the coin mechanism will accept coins). The sensor
indicator light will blink upon impact on the delivery
chute. Lightly tap the chute with a tool, or your fist, to
simulate a can drop.
1. Locate the Sensor Adjustment Indicator Lamp on the
lower right corner of the Vender’s Control Board.
Under normal conditions (as in stand-by), the lamp
should be off.
2. Test the sensor by vending from column 7 and
12 while watching the Control Board’s Sensor
Adjustment Indicator Lamp. The light should
blink solidly upon impact. If not, turn the sensor
adjustment screw clockwise in 1/4 turn increments
(to increase the sensitivity) and test after each turn.
If the indicator lamp still does not light, turn the
adjustment screw clockwise for many turns. If the
indicator lamp does not light, change the sensor
(assuming the Control Board has power and is
working).
3. If the Sensor Adjustment Indicator Lamp lights
properly during Step 2, change the Control Board.
4. Test the sensor by hitting the center of the delivery
chute while watching the control board’s sensor
adjustment indicator light. The light should blink
solidly upon impact.
Section 2. Vender Component Explanation

17
Merlin IV Service and Parts Manual
Section 2. Vender Component Explanation
REFRIGERATION SYSTEM
The vender’s refrigeration system is responsible for the
cooling of the cabinet and the products loaded within
it. The refrigeration system comes as a completely
sealed unit and should never be cut or tapped into, or the
warranty will be voided.
OPERATION REQUIREMENTS: The refrigeration
system requires 115 volts AC from the main wiring
harness for it to operate. The main wiring harness will get
its voltage for the unit from the refrigeration relay.
HEALTH SENSOR OPERATION (if enabled): The
rising temperature in the cooling compartment is reported
to the control board by the temperature sensor. At power
up, the controller will check for the temperature. If the
temperature is above 41°F (5°C), the vender will display
“Out of Order.” Once the “hS” error has been cleared, a
30-minute timer will begin. At the end of this 30 minutes,
the vender will stay in normal operating mode as long
as the temperature remains 41°F (5°C) or below. If the
vender is 41°F (5°C) or below at power up, the vender
will stay in normal operating mode. If the door is open
after power up and the temperature is 41°F (5°C) or below
and stays at 41°F (5°C) or below, a 30-minute timer will
start after the door is closed. If the temperature is above
41°F (5°C) after 30 minutes, the vender will display “Out
of Order.” Any time the vender is in a normal operating
mode and the temperature reaches above 41°F (5°C),
a 15-minute timer will start. If after 15 minutes the
temperature remains above 41°F (5°C), the vender will
display “Out of Order.”
REFRIGERATION COMPONENTS: The refrigeration
system is a sealed system. Described in this section
are explanations of the refrigeration system’s major
components.
Compressor - The compressor is an hermetically-sealed
unit located beneath (outside) the cooling compartment.
The compressor is a pump, driven by the compressor
motor which draws low-pressure vapor (refrigerant) from
the evaporator coil, compresses it, and forces it into the
condenser under high pressure. The motor is started and
controlled by the refrigeration relay.
Condenser - The condenser is located beneath (outside)
the cooling compartment next to the compressor. It
can be seen from the front with the door open. The
condenser removes heat from the high-pressure vapor
discharged from the compressor and condenses it to a
high-pressure liquid. The condenser and evaporator coils
have aluminum fins attached to effectively increase heat
exchange surfaces.
Starting Relay - The starting relay is mounted on the side
of the compressor housing. The compressor motor has
two windings (start winding and run winding). To give
the motor torque when it first starts, the starting relay
switches in the additional start winding. After the motor
gets up to speed, the relay opens the start winding and the
motor continues using only the run winding.
Thermal Overload - The thermal overload is a heat-
sensitive device mounted on the side of the compressor
housing. If the compressor motor gets too hot or draws
an excessive amount of current, the thermal overload
will open, breaking the circuit to the compressor. After
the compressor cools to a safe operating temperature, the
thermal overload will close, allowing the compressor and
condenser fan motors to restart.
Condenser Fan and Motor - The condenser fan and motor,
located beneath the cooling department, are a forced-air
device using outside ambient air to cool the surface of the
condenser coil. The condenser fan and motor run while
the compressor operates.
Evaporator Coil - The evaporator coil is located in the
cooling compartment. As low pressure liquid passes
through the evaporator coil, it absorbs and removes
heat from the compartment as it changes to vapor. The
condenser and evaporator coil have aluminum fins
attached to effectively increase their heat exchange
surfaces.

18 Merlin IV Service and Parts Manual
Evaporator Fan and Motor - The evaporator fan and motor
are a forced-air device circulating air throughout the
cooling compartment and over the heat exchange surface
of the evaporator coil.
Drier - The drier is located in the refrigerant line between
the capillary tube and condenser. It traps and removes
moisture from the refrigeration system while allowing oil
and refrigerant to pass through the system.
Accumulator - The accumulator is located in the
refrigerant line between the evaporator coil and the
compressor. The accumulator traps any liquid refrigerant
which did not vaporize before it reaches the compressor.
Refrigeration Relay - The refrigeration relay is located
in the lower left section of the vender’s cabinet near
the main wiring harness. The refrigeration relay is
responsible for powering the compressor and condenser
fan motors. The refrigeration relay consists of a coil
powered by the control board (24 VDC) and a switch.
When the control board completes the circuit to the
refrigeration relay, the relay will energize, closing the
contact between the common and the normally-open
positions. When this happens, power (115 VAC) travels
from the refrigeration relay to the main wiring harness for
the refrigeration unit.
REFRIGERATION CYCLE
1. The rising temperature in the cooling compartment is
reported to the control board through the temperature
sensor.
2. The control board registers the current temperature
inside the vender’s cabinet. When it rises equal to
or above the pre-programmed cut-in temperature,
the control board will complete the circuit to the
refrigeration relay to energize its coil.
3. The refrigeration relay coil closes the contact between
the common and normally-open positions, allowing
115 volts to travel to the main wiring harness to start
the compressor.
4. The compressor circulates refrigerant throughout the
system by pulling low-pressure refrigerant vapor from
the evaporator coil, compressing it, and forcing it into
the condenser. The condenser, aided by the condenser
fan motor, removes heat from the refrigerant as it
flows through the condenser and releases it to the
outside environment. The dropping of the refrigerant
temperature changes the vapor to liquid.
5. The evaporator coil allows the liquid refrigerant
to absorb heat from the cooling compartment as it
evaporates in the coil.
6. The falling temperature in the cooling compartment
is caused by the continual circulation of refrigerant
through the system, removing heat from the cooling
compartment and transporting it to the outside
environment. When the temperature drops, the
temperature sensor reports this to
the vender’s control board.
7. When the temperature
drops below the preset cut-out
temperature, the control board will
disable the refrigeration relay, thus
killing power to the refrigeration
unit.
Section 2. Vender Component Explanation
COMPRESSOR
Discharge
Suction
Condensor
Fan Motor
Evaporator
Fan Motor
CONDENSOREVAPORATOR
Drier
REFRIGERATION SYSTEM
Legend
Direction of
Refrigerant
Flow
Accumulator
Capillary
Tube
Figure 2.2. Refrigeration System Flow

19
Merlin IV Service and Parts Manual
TESTING THE REFRIGERATION SYSTEM
1. The sealed refrigeration unit can be tested by
unplugging it from the top of the main wiring harness
and plugging it directly into a power source. If the
unit still does not operate, a problem exists within the
sealed unit.
2. If the sealed unit runs when plugged into an external
power source, the problem more than likely lies
between the control board, the refrigeration relay, and
the main wiring harness.
Section 2. Vender Component Explanation
BALLAST
The ballast acts as a transformer to convert conventional
voltage (115 VAC) to a higher voltage required to
energize the vender’s fluorescent lights. The ballast is
located inside the vender’s door, behind a metal panel.
To remove the ballast from the door, use a Phillips
screwdriver to remove the screws that mount the ballast to
the door chassis.
WARNING: Before removing the
ballast, remove power from the vender
by unplugging the main power cord
from theAC voltage power source!
CREDIT PERIPHERALS
There are three possible credit peripherals for the Merlin
IV vender: the coin changer, bill acceptor, and debit
card reader. The coin changer determines the validity
and value of each coin that is inserted into the vender
and sends the coin information to the controller. The
coin changer also continuously informs the controller
if coins are available in the change tubes to be used
for change payout. The bill acceptor determines the
validity and value of each bill that is inserted and sends
that information to the controller. The debit card reader
allows customers to purchase a product using a debit or
credit card. For detailed information on any of the credit
peripherals, refer to the separate operation and service
manual provided by the peripheral’s manufacturer.
WARNING
ELECTROCUTION HAZARD
When plugging the refrigeration unit directly into
a wall outlet or other external electrical source,
the refrigeration unit MUST remain in the vender
for proper grounding. If the unit is removed from
the vender, an electrocution hazard exists.

20 Merlin IV Service and Parts Manual
Section 3. Vender Programming
Vender Programming
THE NECESSITY OF CORRECT
PROGRAMMING
The MERLIN IV vender must be programmed correctly
for it to operate properly. Improper programming could
potentially cause the following problems:
MODE PROBLEM SEEN
Pric Wrong prices, free vending
StoS Columns not vending or wrong columns
vending
Con Vender options such as forced vend / escrow
not working properly
SdEP Vender multiple vending or long vend cycles
StCL If enabled with use of timer or key switch,
will disable selections
tinE Will disable selections or Refrigeration
System if turned on
FriG Will keep the unit from running or allow
warmer / colder temperatures
PAS Will keep you from accessing the external
password mode
LAnG Will display different languages for display
messages
PRECAUTIONS TO TAKE WHEN
WORKING WITH CONTROL BOARD
As with any printed circuit board, our electronics are
very sensitive to electrostatic discharge (ESD). Simply
walking across a tile, or carpeted floor, can generate a
range of 30,000 to 50,000 volts of electricity. One ESD
can be enough to seriously damage your control board,
or at least weaken it enough that erratic problems could
occur in the future. Even a discharge surge under 100
or 200 volts is enough to create shorts or other problems
within the circuitry of the electronics. It is advised when
storing the electronics that they be kept in their anti-static
bags, even if the electronics are thought to be defective.
If a control board is thought to be defective and is
really not, it soon will be after being charged with ESD.
The ideal prevention against ESD is to use anti-static
conductive wrist straps which ground you to the machine
before touching the electronic boards. If it is not possible
to use these, at least ground yourself before handling the
electronic boards. Whatever method you use, always
handle the electronic boards by the edges. Be careful not
to touch the components on the control board.
INTRODUCTION TO PROGRAMMING
As mentioned earlier in “The Necessity Of Correct
Programming,” it is very important your vender is
programmed properly. To do this, you must understand
how the system works and what it takes to program your
vender. As you will see, after you are able to program one
or two modes, you will be able to use similar procedures
to program all modes.
MANEUVERING THROUGH LEVELS - The first step
to understanding MERLIN IV programming is to learn
how to negotiate through and around the menu levels to
accomplish your task. To maneuver through the menu
levels, you must use the select buttons on the front of your
vender. Certain buttons have different meanings. You
will use these buttons to move up or down through the
menus. You will also use certain buttons to enter a new
menu level or to exit back to a previous level. These four
meanings that we have just mentioned are listed below,
along with the active button for each.
NOTE: Programming Flowchart located in rear of
manual.
BUTTON MEANING FUNCTION
1 UP Increase, Next, Etc.
2 DOWN Decrease, Previous,
Etc.
3 ENTER Save,Accept, OK, Etc.
[press and release,
less than two
seconds]
3 HOME Exit, Escape, Return,
[press & hold Etc.
for two seconds
or greater]
MENU SYSTEM - When programming, you must
first use the three programming buttons listed above to
maneuver through menus and sub-menus before you will
be allowed to accomplish your task. Each menu consists
of various items, or modes, such as “Pric” (Selection
Price Setting Mode) or “StoS” (Space-to-Sales Setting
Mode). There are currently two different main menus
available.