Merit Mod box deluxe Instruction manual

PM0564-03

MoD BoX Deluxe

Amplifier Accessory Board

Connection Instructions

Amplifier Accessory Board Connection Instructions

Introduction:

This instruction shows you how to connect the accessory board to external audio

equipment, so please read all of this introductory material.

You should save these instructions for future reference. Many different connection

schemes are possible, and additional options and configurations can be added to existing

connections.

If you want to use the accessory board in a configuration that is not described, or if you

have difficulty installing one of the configurations, refer to the accessory board block

diagram (Figure 13), schematic diagram (Figure 14), and the installation tips and tech-

niques at the end of this installation instruction.

IMPORTANT: FOR PAGING AND MICROPHONE CAPABILITY YOU

WILL NEED KIT KOV-106-000-06, -09 OR -10. (SEE PAGE 35 OF

YOUR MOD BOX OWNERS MANUAL.)

PM0564-03 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS 1

Preparation

Before you begin, study the configuration that you wish to use to determine which

jumpers and audio cables will be needed to complete the installation (external cables for

connecting from the accessory board to other equipment must be purchased or as-

sembled).

When you have obtained all of the cables, continue with the installation.

External Connections

You are now prepared to connect the external devices. There are 4 different and

independent types of connections possible. You can connect:

•up to 2 microphones

•an external preamplifier (used for tone and volume control for the entire system)

•an external music source

•a separate external amplifier

The following paragraphs, along with the accessory board block diagram (Figure 3) and

schematic diagram (Figure 4), describe these connections.

PAGING MICROPHONE CONNECTIONS

The MoD BoX Paging Kit (part #KOV-106-000-06) is available through your local

authorized dealer.

2 Microphones

Plug the 5-way header of the first EC1918-01 microphone cable (part of MoD BoX Paging

Kit) into the microphone input header on the preamplifier. (This is a piggyback connection.)

Plug the 5-way header of the EC1918-01 microphone cable for the second microphone

into P3 of the amplifier accessory board.

1 Microphone

Plug the 5-way header of the EC1918-01 microphone cable into P3 of the amplifier

accessory board.

2 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS PM0564-03

INDEX TO CONNECTION INFORMATION

Connection

External Preamplifier .................................................................................................... p. 4

Input

Stereo Background Music Input (Background Music, Tuner, TV) .............................. p. 5

Mono Background Music Input (Background Music, Tuner, TV) ................................ p. 6

Background Level and Switch-In Time Delay Adjustments ...................................... p. 7

Stereo Auxiliary Music Input (Tuner, TV, Turntable, etc.) ........................................... p. 8

External Amplifier (Choose only one of these connection schemes)

External Stereo Amplifier (Volume/Tone Controlled by Jukebox Preamp) .................. p. 9

External Mono Amplifier (Volume/Tone Controlled by Jukebox Preamp) .................... p. 10

External Stereo Amplifier (Volume/Tone Independent of Jukebox) ............................ p. 11

External Mono Amplifier (Volume/Tone Independent of Jukebox) .............................. p. 12

PM0564-03 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS 3

External Preamplifier

Use this configuration if you want the volume and tone of the entire jukebox sound system

to be controlled by an external preamplifier. This configuration uses the AVC portion of the

jukebox’s preamp, but bypasses its tone and volume controls.

Instructions

Cables and Jumpers

Obtain four shielded audio cables long enough to reach between the external preamp and

the amplifier accessory board.

This configuration requires only one of the three jumpers supplied with the accessory

board. Connect this jumper between:

1. J9 (LH CH INPUT) and J14 (INVERTER OUTPUT).

Input and Output Connections

Connect the input to the external preamp as follows:

1. Preamp RIGHT CH INPUT to J4 (RIGHT CH PREAMPAUX OUTPUT)

2. Preamp LEFT CH INPUT to J2 (LEFT CH PREAMPAUX OUTPUT)

Connect the external preamp output as follows:

1. External preamp RIGHT CH OUTPUT to J12 (RIGHT CH POWER AMP INPUT)

2. External preamp LEFT CH OUTPUT to J10 (INVERTER INPUT)

WARNING: Be sure that the equipment you are connecting to

the Jukebox has an isolation transformer type power supply.

Equipment that does not have an isolation transformer can

damage the jukebox and/or create a shock hazard.

FIGURE 4 - EXTERNAL PREAMP CONNECTIONS

4 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS PM0564-03

J1 J2 J3 J4 J5

AUX.

INTERCONNECT

SWITCH IN

TIME ADJUST

FOR BGM

P3 P4

J12 J13

J19 J20J18

J17J16

J11

J10J9

J15

J14

J6 BGM

MUSIC

LEVEL

ADJUST

PREAMP/POWER AMP INTERCONNECT

STEREO PREAMP

USED FOR TONE

AND VOLUME

CONTROL

OUT

Instructions

Cables and Jumpers

Obtain two shielded audio cables long enough to reach between the input device (FM radio,

TV, tape player, etc.) and the amplifier accessory board.

This configuration requires all three jumpers supplied with the accessory board. Connect

these jumpers between:

1. J9 (LEFT CH POWERAMP INPUT) and J14 (INVERTER OUTPUT).

2. J13 (RIGHT CH POWERAMP INPUT) and J20 (RIGHT CH PREAMP OUTPUT).

3. J11 (INVERTER INPUT) and J16 (LH CH OUTPUT).

Input Level Considerations

The background music input can accept a wide range of input levels. You can connect

speaker lines, aux. outputs or line outputs.

Stereo Background Music Input

Connect a stereo device as described here to provide background music from an external

source during periods that the jukebox is not playing a paid selection. The volume of this

music (generally lower than paid selections) is adjusted on the amplifier accessory board as

described on Page 9. The jukebox preamplifier settings are used for tone control. A device

connected to this input will not be heard during pages, or while the jukebox is playing a

selection.

WARNING: Be sure that the equipment you are connecting to

the Jukebox has an isolation transformer type power supply.

Equipment that does not have an isolation transformer can

damage the jukebox and/or create a shock hazard.

Input Connections

Connect the input cable from the music

source as follows:

1. RIGHT CHANNEL J8 (RH CH BGM)

2. LEFT CHANNEL J6 (LH CH BGM)

FIGURE 5 - STEREO BACKGROUND MUSIC CONNECTIONS

PM0564-03 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS 5

J1 J2 J3 J4 J5

AUX.

INTERCONNECT

SWITCH IN

TIME ADJUST

FOR BGM

P3 P4

J12 J13

J19 J20J18

J17J16

J11

J10J9

J15

J14

J6 BGM

MUSIC

LEVEL

ADJUST

PREAMP/POWER AMP INTERCONNECT

STEREO MUSIC

SOURCE FOR

JUKEBOX

Instructions

Cables and Jumpers

Obtain one shielded audio cable long enough to reach between the input device (FM radio,

TV, tape player, etc.) and the amplifier accessory board.

This configuration requires all three jumpers supplied with the accessory board. Connect

these jumpers between:

1. J9 (LEFT CH POWERAMP INPUT) and J14 (INVERTER OUTPUT).

2. J13 (RIGHT CH POWERAMP INPUT) and J20 (RIGHT CH PREAMP OUTPUT).

3. J11 (INVERTER INPUT) and J16 (LH CH OUTPUT).

Input Level Considerations

The background music input can accept a wide range of input levels. You can connect

speaker lines, aux. outputs or line outputs.

WARNING: Be sure that the equipment you are connecting to

the Jukebox has an isolation transformer type power supply.

Equipment that does not have an isolation transformer can

damage the jukebox and/or create a shock hazard.

Mono Background Music Input

Connect a mono device as described here to provide background music from an external

source during periods that the jukebox is not playing a paid selection. The volume of this

music (generally lower than paid selections) is adjusted on the amplifier accessory board as

described on Page 9. The jukebox preamplifier settings are used for tone control. A device

connected to this input will not be heard during pages, or while the jukebox is playing a

selection.

Input Connections

Connect the input cable from the

music source as follows:

1. Music source output to J7

(BGM MONO)

FIGURE 6 - MONO BACKGROUND MUSIC CONNECTIONS

6 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS PM0564-03

J1 J2 J3 J4 J5

AUX.

INTERCONNECT

SWITCH IN

TIME ADJUST

FOR BGM

P3 P4

J12 J13

J19 J20J18

J17J16

J11

J10J9

J15

J14

J6 BGM

MUSIC

LEVEL

ADJUST

PREAMP/POWER AMP INTERCONNECT

MONO MUSIC

SOURCE FOR

JUKEBOX

Background Level and Switch-In Time Delay Adjustments

Background Level Adjustment

1. Select a song from the jukebox and make sure that the jukebox volume is at the desired

level.

2. Cancel the song, turn the SWITCH-IN TIME adjustment clockwise as far as it will go.

3. When the background music begins to play (in approximately 10 seconds), adjust the

BGM MUSIC LEVEL control for the desired background music level.

Switch-In Time Adjustment

The Switch-In Time can be adjusted from a minimum of approximately 10 seconds to a

maximum of approximately two minutes. To set this time:

1. Make another selection. While the song is playing, turn the SWITCH-IN TIME ADJUST

(see Figure 2) fully clockwise (it should already be in this position if you have just

finished the background music adjustment). Cancel the music. Approximately 10

seconds after the selection finishes, the background music will begin playing.

2. Turn the SWITCH-IN TIME ADJUST control counter clockwise slightly, play and cancel a

record, and note the switch-in time.

3. Repeat step 2 until the desired switch-in time is reached.

BGM LEVELADJUST

SWITCH-IN TIME

FIGURE 7 - ADJUSTMENT LOCATIONS ON AMPLIFIERACCESSORY BOARD

PM0564-03 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS 7

Instructions

IR Remote Kit

You must obtain and install Kit # KOV-106-000-07.

Cables and Jumpers

Obtain two shielded audio cables long enough to reach between the input device (FM radio,

TV, tape player, etc.) and the amplifier accessory board. Install an appropriate switch box

as illustrated below.

This configuration requires all three jumpers supplied with the Accessory Board.

Connect these jumpers between:

1. J9 (LEFT CH POWERAMP INPUT) and J14 (INVERTER OUTPUT).

2. J13 (RIGHT CH POWERAMP INPUT) and J20 (RIGHT CH PREAMP OUTPUT).

3. J11 (INVERTER INPUT) and J16 (LH CH OUTPUT).

Input Connections

Connect the input cable

from the music source

as follows:

1. RIGHT CHANNEL J5

(RIGHT CH AUX IN)

2. LEFT CHANNEL J1

(LEFT CH AUX IN)

FIGURE 8 - STEREO AUXILIARY MUSIC CONNECTIONS

WARNING: Be sure that the equipment you are connecting to

the Jukebox has an isolation transformer type power supply.

Equipment that does not have an isolation transformer can

damage the jukebox and/or create a shock hazard.

Stereo Auxiliary Music Input

You can connect a stereo device as described here, but you must suspend normal jukebox

operation while playing from this source. To do this, you must use the “Power” button on the

optional MoD BoX Infrared Remote Control. This will suspend jukebox operation while play-

ing the external source through the MoD BoX Amplifier and speakers (jukebox selections will

remain in queue and will resume when the “Power” button is pressed again). The jukebox

tone and volume controls will be used for this source as well as when the jukebox is playing

normally. Quick-disconnect or switching means should be included so that the external

source can be disconnected when restoring normal jukebox operation to prevent both

music programs from being fed to the amplifier simultaneously.

8 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS PM0564-03

J1 J2 J3 J4 J5

AUX.

INTERCONNECT

SWITCH IN

TIME ADJUST

FOR BGM

P3 P4

J12 J13

J19 J20J18

J17J16

J11

J10J9

J15

J14

J6 BGM

MUSIC

LEVEL

ADJUST

PREAMP/POWER AMP INTERCONNECT

STEREO MUSIC

SOURCE FOR

JUKEBOX

PREAMPLIFIER

DISCONNECT

WARNING: Be sure that the equipment you are connecting to

the Jukebox has an isolation transformer type power supply.

Equipment that does not have an isolation transformer can

damage the jukebox and/or create a shock hazard.

External Stereo Amplifier Connection - Juke Controlled

To drive extra speaker loads with an external stereo amplifier, use this configuration if

you want its volume and tone to be controlled by the jukebox tone and volume controls.

Instructions

Cables and Jumpers

Obtain two shielded audio cables long enough to reach between the external amplifier

and the amplifier accessory board.

This configuration requires all three jumpers supplied with the accessory board. Connect

these jumpers between:

1. J9 (LEFT CH POWERAMP INPUT) and J14 (INVERTER OUTPUT).

2. J13 (RIGHT CH POWERAMP INPUT) and J20 (RIGHT CH PREAMP OUTPUT).

3. J11 (INVERTER INPUT) and J16 (LH CH PREAMP OUTPUT).

Input Level Considerations

The background music input can accept a wide range of input levels. You can connect

speaker lines, aux. outputs or line outputs.

Input Connections

Connect the input cable from the external amplifier to the accessory board as follows:

1. Connect the external amplifier’s RIGHT CH INPUT to J19 (RIGHT CH PREAMP OUTPUT).

2. Connect the external amplifier’s LEFT CH INPUT to J15 (LEFT CH PREAMP OUT).

FIGURE 9 - STEREO EXTERNAL CONNECTIONS (CONTROLLED BY JUKEBOX VOLUME)

PM0564-03 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS 9

Note: The pre-amplifier will mute

between selections

J1 J2 J3 J4 J5

AUX.

INTERCONNECT

SWITCH IN

TIME ADJUST

FOR BGM

P3 P4

J12 J13

J19 J20J18

J17J16

J11

J10J9

J15

J14

J6 BGM

MUSIC

LEVEL

ADJUST

PREAMP/POWER AMP INTERCONNECT

STEREO EXTERNAL

AMPLIFIER

Instructions

Cables and Jumpers

Obtain a shielded audio cable long enough to reach between the external amplifier and

the amplifier accessory board.

This configuration requires all three jumpers supplied with the Accessory Board.

Connect these jumpers between:

1. J9 (LEFT CH POWERAMP INPUT) and J14 (INVERTER OUTPUT).

2. J13 (RIGHT CH POWERAMP INPUT) and J20 (RIGHT CH PREAMP OUTPUT).

3. J11 (INVERTER INPUT) and J16 (LH CH OUTPUT).

Input Connections

Connect the input cable from the external amplifier to the accessory board as follows:

1. Connect the input cable from the external amplifier INPUT to J18 (PREAMP MONO

OUTPUT).

WARNING: Be sure that the equipment you are connecting to

the Jukebox has an isolation transformer type power supply.

Equipment that does not have an isolation transformer can

damage the jukebox and/or create a shock hazard.

External Mono Amplifier Connection - Juke Controlled

To drive extra speaker loads with an external monaural amplifier, use this configuration if

you want its volume and tone to be controlled by the jukebox tone and volume controls.

FIGURE 10 - MONO EXTERNALAMPLIFIER CONNECTIONS

(CONTROLLED BY JUKEBOX VOLUME)

10 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS PM0564-03

J1 J2 J3 J4 J5

AUX.

INTERCONNECT

SWITCH IN

TIME ADJUST

FOR BGM

P3 P4

J12 J13

J19 J20J18

J17J16

J11

J10J9

J15

J14

J6 BGM

MUSIC

LEVEL

ADJUST

PREAMP/POWER AMP INTERCONNECT

MONO SLAVE

AMPLIFIER

Note: The pre-amplifier will mute

between selections

WARNING: Be sure that the equipment you are connecting to

the Jukebox has an isolation transformer type power supply.

Equipment that does not have an isolation transformer can

damage the jukebox and/or create a shock hazard.

External Stereo Amplifier Connection - No Juke Control

To drive extra speaker loads with an external stereo amplifier, use this configuration if

you wish to use the volume and tone controls of the external amplifier.

Instructions

Cables and Jumpers

Obtain two shielded audio cables long enough to reach between the external amplifier

and the amplifier accessory board.

This configuration requires all three jumpers supplied with the accessory board. Connect

these jumpers between:

1. J9 (LEFT CH POWERAMP INPUT) and J14 (INVERTER OUTPUT).

2. J13 (RIGHT CH POWERAMP INPUT) and J20 (RIGHT CH PREAMP OUTPUT).

3. J11 (INVERTER INPUT) and J16 (LH CH OUTPUT).

Input Connections

Connect the input cable from the external amplifier to the accessory board as follows:

1. Connect the external amplifier LEFT CH INPUT to J2 (LEFT CH AUX. OUTPUT).

2. Connect the external amplifier RIGHT CH INPUT to J4 (RIGHT CH AUX. OUTPUT).

PM0564-03 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS 11

J1 J2 J3 J4 J5

AUX.

INTERCONNECT

SWITCH IN

TIME ADJUST

FOR BGM

P3 P4

J12 J13

J19 J20J18

J17J16

J11

J10J9

J15

J14

J6 BGM

MUSIC

LEVEL

ADJUST

PREAMP/POWER AMP INTERCONNECT

STEREO EXTERNAL

AMPLIFIER

Note: The amplifier will not

mute between selections

FIGURE 11 - STEREO EXTERNALAMPLIFIER CONNECTIONS

(INDEPENDENT OF JUKEBOX VOLUME)

WARNING: Be sure that the equipment you are connecting to

the Jukebox has an isolation transformer type power supply.

Equipment that does not have an isolation transformer can

damage the jukebox and/or create a shock hazard.

External Mono Amplifier Connection - No Juke Control

To drive extra speaker loads with an external monaural amplifier, use this configuration if

you wish to use the volume and tone controls of the external amplifier.

Instructions

Cables and Jumpers

Obtain a shielded audio cable long enough to reach between the external amplifier and

the amplifier accessory board.

This configuration requires all three jumpers supplied with the accessory board. Connect

these jumpers between:

1. J9 (LEFT CH POWERAMP INPUT) and J14 (INVERTER OUTPUT).

2. J13 (RIGHT CH POWERAMP INPUT) and J20 (RIGHT CH PREAMP OUTPUT).

3. J11 (INVERTER INPUT) and J16 (LH CH OUTPUT).

Input Connections

Connect the input cable from the external amplifier to the accessory board as follows:

1. Connect the external amplifier INPUT to J3 (AUX. OUTPUT MONO).

FIGURE 12 - MONO EXTERNALAMPLIFIER CONNECTIONS

(INDEPENDENT OF JUKEBOX VOLUME)

12 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS PM0564-03

J1 J2 J3 J4 J5

AUX.

INTERCONNECT

SWITCH IN

TIME ADJUST

FOR BGM

P3 P4

J12 J13

J19 J20J18

J17J16

J11

J10J9

J15

J14

J6 BGM

MUSIC

LEVEL

ADJUST

PREAMP/POWER AMP INTERCONNECT

MONAURAL

EXTERNAL

AMPLIFIER

INPUT

Note: The amplifier will not

mute between selections

FIGURE 13 - ACCESSORY BOARD BLOCK DIAGRAM

PM0564-03 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS 13

PHONOGRAPH

CARTRIDGE

MONO/STEREO

SWITCH

RIAA

COMPENSATED

AMPLIFIER

RIAA

COMPENSATED

AMPLIFIER

LEFT

CHANNEL

AV C

CONTROL

RIGHT

CHANNEL

AV C

AUX.

INPUT

AUX.

INPUT

AUX.

OUTPUT

MONO

AUX. OUT

AUX.

OUTPUT

BACKGROUND

MUSIC INPUT

PREAMP MONO

OUTPUT

TONE AND

VOLUME

CONTROL

CIRCUIT

TONE AND

VOLUME

CONTROL

CIRCUIT

INVERTER POWER

AMPLIFIER

POWER

AMPLIFIER

J19

J20

J12

J13

J18

J16

J17

J10

J11

J14

J15 J9

J2J1

RIGHT CHANNEL

LEFT CHANNEL

FIGURE 14 - ACCESSORY BOARD SCHEMATIC DIAGRAM

14 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS PM0564-03

GROUND COMPLETED

ON PREAMP BOARD

AUX

INTERCONNECT

1 2 4 5 3

MIC INTRCONNECT NOTE:

THIS MUST BE CONNECTED

TO MIC INPUT ON AMPLIFIER

FOR PROPER OPERATION

1 3 2 4

MIC

INPUT

1 4 3 5 2

1 MFD

R15

100K

Z1 LM358

7Z1

CR1

MP5A06

CR3

SLOW

3.9 MEG

FAST

R10

15 K

10 K

2 K

TIME ADJUST

INVERTER OUTPUT

INVERTER INPUT

PREAMP OUTPUT

(LT CH)

PREAMP OUTPUT

(RT CH)

PREAMP GROUND

POWER AMP INPUT

(RT CH)

POWER AMP INPUT

(LT CH)

+12.5 VDC

MUTE SENSE

BGM INPUT (SWITCHED)

JUMPER PLUG

NOTE:

ONLY USED WHEN ACCESSORY

BOARD IS NOT USED.

PREAMP

CONNECTOR

FOR INFORMATION ON

THE ABOVE CONNECTIONS

REFER TO 607925XX

PREAMP SCHEMATICS

PREAMP/POWER AMP

INTERCONNECT

NOTE:

NORMAL OPERATION (JUMPER LOCATION)

JUMPER 1 RT CH PREAMP OUTPUT (J20) TO RT CH POWER AMP INPUT (J13).

JUMPER 2 L CH PREAMP OUTPUT (J16) TO (J9) LEFT CH POWER AMP INPUT

UNLESS OTHERWISE NOTED:

ALL CAPACITORS ARE RATER IN uF.

ALL RESISTORS ARE 1/4 W +-5% AND RATED IN OHMS.

L CH POWER AMP

INPUT

L CH PREAMP

OUTPUT

INVERTER

OUTPUT

J9 J15

J14

J17

J16

J11

J10

INVERTER

INPUT

3.3 K

J19J20R14

R13

RT CH

PREAMP OUTPUT

J18

PREAMP

MONO

OUTPUT RT CH

POWER AMP

INPUT

J12 J13

R11

47 K

3.3 K

BGM

MONO INPUT

CR4

R12

10 K

3.3 K

BGM

MUSIC LEVEL

ADJUST

INPUT

BGM

STEREO

INPUT

R. CH

L. CH

3.3 K

RT CH AUX OUTPUT

AUX OUTPUT MONO

L CH AUX OUTPUT

L CH AUX INPUT

RT CH AUX INPUT

J1 J5

COMPONENT LIST FOR CIRCUIT BOARD ASSEMBLY -

PREAMP ACCESSORY BOARD

PM0564-03 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS 15

FIGURE 15 - EC1942-01 HARNESS ASSEMBLY -

ACCESSORY BOARD TO PREAMPAUX INPUT

FIGURE 16 - EC1939-01 HARNESS ASSEMBLY -

PREAMP/ACCESSORY BOARD INTERCONNECT

FIGURE 17 - EC1940-01 HARNESS ASSEMBLY -

ACCESSORY BOARD TO PREAMP MIC INPUT

16 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS PM0564-03

BROWN

RED/WHITE

YELLOW

BLACK

ORANGE

GREEN

BLUE

RED

SHIELD

WHITE/ORANGE

ORANGE

BLACK

YELLOW

RED/WHITE

BROWN

SHIELD

RED

BLUE

GREEN

WHITE/ORANGE

24.50

22.00

RED

SHIELD

GREEN

SHIELD

GREEN

SHIELD

RED

SHIELD

INSTALLATION TIPS AND TECHNIQUES

If you are having difficulty with your accessory board installation, review the following

list of installation tips for the problem that matches or nearly matches your situation.

Excessive Hum

The primary cause of hum is poor grounding. Make sure that each audio line connecting

the accessory board to the added equipment has a good ground at both ends. If the

wires are soldered, check for cold solder connection. If the ground connections are

crimped, look for an incomplete or forgotten crimp.

If the audio grounding is not the fault, you might have a voltage difference between the

jukebox and the added equipment. To check for this condition, unplug one cable at a time,

and measure the voltage between the ground on the cable and the Jukebox ground. You

should not be able to measure any AC or DC voltage between the two units. If you do

measure any voltage, you must isolate the added equipment from the power line.

Sometimes this can be avoided by reversing the 120 volt plug (2-prong plugs only).

If the added equipment is causing the hum and the hum is due to a voltage differential, but

the 120 plug on the equipment has a 3-prong plug, we do not advise using an isolation

plug to correct the problem. In this situation, it is suggested that you have a competent

repair center make the needed repairs.

Noise Between Audio Selections

This condition can exist if you have chosen a configuration which does not allow the

jukebox mute circuit to quiet the jukebox between selections. If this condition exists,

consult a competent electronics technician or engineer for the circuit necessary to mute

the specific added equipment and jukebox combination.

Cross talk

Cross talk can exist when an external preamp is used between the tone and volume

circuits (J16, J17 and J19, J20) and the power amplifier (J10, J11 and J12, J13). Cross

talk will exist because R13 and R14 (see schematic - Figure 14) will “mix” the left and

right channel signals.

To correct this problem, make a shorting plug (connect the center of the plug to the case)

and plug it into J18.

FIGURE 18 - SHORTING PLUG

PM0564-03 MOD BOX AMPLIFIER ACCESSORY BOARD CONNECTIONS 17

SOLDER HERE

NOTES:

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