Technical Service Bulletin csbull16 – Dart Game False Dart Count (R9 Resistor Fix)

Technical service bulletin correcting darts counted as thrown on dart games with switching power supplies by verifying the R9 resistor on the RDP28 board.

TSB-KSD-100-001 - 2-9-96

Customer Service Bulletin

Csbull16.doc

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Date: 2/9/96

merit industries, inc.

Problem:

Darts being counted as “thrown,” without a dart being thrown.

Games affected:

All dart games with switching power supplies. Serial numbers
425766 and up (uprights) and 460482 and up (wall mounts)

Symptoms:

Darts are taken away; a player gets fewer than 3 darts per turn.

Cause:

Improper voltage.

Solution:

Ensure proper voltage by following the steps below.

Instructions

Step 1 - Check R9 Resistor on the RDP28 Target/Microphone Interface Board

1. The resistor located at R9 on the RDP28 board should have a resistance value of

470K

Ω (color code YELLOW/VIOLET/YELLOW/GOLD). If the R9 resistor does not

have a resistance value of 470K

Ω, the resistor should be changed. Games with

serial number 428672 or higher were manufactured with the resistor modification. If
you do not have the resistor, contact Merit Customer Service (1-800-445-9353) and
order part number RS1800.

Step 2 - Securing the Power Connector

1. Inspect for cold solder joints on the power supply’s main power connector. Resolder

each of the connector’s pins if this problem is suspected. (See Figures 1 and 2 for
header locations.)

Step 3 - Set the Proper Voltage Level to CPU board & Add Additional +5 Volt Wires

Required parts: (To order these parts pre-assembled, contact Merit Customer Service
and order kit # KSD-100-001)

Upright games:

(2) 261/2” lengths of 18 AWG wire

Wall games:

(2) 14” lengths of 18 AWG wire

All games:

(2) 0.156 header pins
(1) 0.093 female pin

1.  Strip 1/4” of insulation off of each end of the wires.
2.  Crimp a 0.156 header pin to one end of EACH wire.
3.  Crimp the remaining ends together into the 0.093 female pin.
4.  Insert the 0.093 female pin into Pin 2 of the J1 connector on the CPU board. (Pin 2

is the only unused pin in the connector.) See Figure 3.

5. Insert the other ends into Pins 2 and 3 of the power supply main header (see

Figures 1 and 2 for header location).

6. Tie wrap the wires to the existing power supply harness.

TSB-KSD-100-001 - 2-9-96

Customer Service Bulletin

Csbull16.doc

Step 4 - Check the Power Supply for Proper Voltage & Test Missed Dart Sensitivity

1. Lower the voltage from the power supply to +5V. (To check the voltage, attach a

voltage meter to the middle pins on the J1 connector on the main CPU board: see
Figure 3 for location of positive and negative voltage.) (See Figures 1 and 2 for
adjusting the power supply output of your power supply. If your game uses an Autec
Power Systems power supply, see Figure 1; if your game uses an International
Power Sources power supply, see Figure 2.)

1. Next, enter the Missed Dart Detector/Automatic Player Change Test (found in your

owner’s manual). The Player 1 lamp should light when the target section is tapped
gently. If the light stays on without a tap, there is a bad chip on the RDP28
microphone board; call Merit Customer Service to order a new RDP28 board. If this
test is passed, raise the voltage back to between +5.15V +5.17V.

Figure 1 - Autec Power

Systems Power Supply

Figure 2 - International Power

Sources Power Supply

Figure 3 - Location of J1 Header on CPU Board

Main Header

VR1 Output
Control

Pin 2

Pin 3

VR1 Output

Control

Pin 2

Pin 3

J1 Header

Main CPU
Board

Pin 2

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