Sega/Stern White Star Repair

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1 Introduction

Typical Early Stern White Star Boardset

2 Games

2.1 Sega

• Apollo 13
• Goldeneye
• Twister
• Independence Day
• Space Jam
• Star Wars Trilogy
• The Lost World Jurassic Park
• The X Files
• Starship Troopers
• Viper Night Driving
• Lost in Space
• Godzilla
• Harley-Davidson
• South Park

2.2 Stern

• Striker Xtreme
• Sharkey's Shootout
• High Roller Casino
• Austin Powers
• Monopoly
• NFL
• Playboy
• Roller Coaster Tycoon
• The Simpsons Pinball Party
• Terminator 3: Rise Of The Machines
• The Lord Of The Rings
• Ripley's Believe It Or Not
• Elvis
• Grand Prix
• The Sopranos
• NASCAR

3 Technical Info

3.1 The White Star Board Set

3.1.1 CPU / Sound Board

Stern White Star CPU/Sound Board 520-5136-16

>>>Image of White Star modified CPU/Sound board should go here<<<

There are two versions of the White Star CPU/Sound board. The board as used in Sega machines starting at Apollo 13 (A13) and Stern machines up to Terminator 3 (T3) are the standard version as shown above which is part #520-5136-16. Stern machines starting from Lord of the Rings (LOTR) used a different version of the White star CPU/Sound board called White Star modified, part #520-5300-00. Stern had this in-between version made because the BSMT2000 audio chip wasn't available anymore and having it reproduced was too expensive. The White Star modified therefore uses an BSMT2000 emulation circuit consisting of an Atmel AT91R40008 microcontroller and an Atmel AT49BV1614 16Mbit flash memory. It is backwards compatible with the standard version so it can be used in Sega White Star based games and White Star based games from Stern prior to LOTR as well.

The BSMT2000 based White Star sound system is basically the same as the sound circuitry on Data East/Sega soundboards 5020-5050-0x, 5020-5077-00 and 5020-5126-02.

There are some programmed TIBPAL16L8 PAL chips on the board, these are programmable logic chips. They have a color dot on them so they can be recognized. U213 is one of these chips and it's right in the battery corrosion area. It is readily available, already programmed under part number 965-6504-00 (blue dot), the only exceptions to that are Sharkey's shootout using part number 965-5023-00 (gold dot) and Lord of the Rings LE with a shaker motor installed using a different part number (the standard LOTR without a shaker motor uses the standard 965-6504-00 but the software version supporting the shaker motor will only run on the alternative U213).

There are two more PAL chips on the board at U19 (yellow dot, 965-0136-00) and U20 (white dot, 965-0137-00). These aren't needed very often for repairing sound boards but they do go bad now and then. Data retention for these programmable logic chips is generally specified at 20 years or more. The first Whitestar boards are from 1995 so from 2015 they start exceeding the data retention period and although big problems are not to be expected it wouldn't be unlikely when more of these start to fail.

The programmable logic in the board design makes it harder to repair the boards because of the grey area it causes in the schematics as there aren't any logic diagrams of these available. In short; you don't know what they do so you don't know what the output should be.

3.1.2 Power Driver Board

Stern White Star I/O Power Driver Board

3.1.3 Display Controller Board

Stern White Star Display Controller Board

3.1.4 Display Power Supply

Stern White Star Display Power Supply

3.1.5 128 x 32 Dot Matrix Display

All Sega or Stern White Star games make use of a 128 x 32 "standard" dot matrix display.

3.2 Recommended Documentation

As always, it is highly recommended to possess a game manual. Every game manual is full of detailed information regarding game specific switch, lamp, and coil assignments. Equally, details for maneuvering through test, audit, and bookkeeping screen menus, schematics for all boards used, and game specific mechanical assemblies are included. Hard copy game manuals can be purchased through several of the recommended pinball parts suppliers.

The Stern Pinball, Inc. website currently archives theory of operation and board schematics in PDF format at the time of this writing. Scroll down to the bottom of the linked page to review the documents available.

3.3 The Wire Coloring Code

White Star games do not use color coding system. Instead, the wire color was marked accordingly in the associated documentation, (ie. a green wire with a brown trace is referred to as GRN-BRN, orange with violet is ORG-VIO, white is just WHT, etc.).

3.7 Trough Opto Boards

Stern White Star Trough Opto Transmitter

Stern White Star Trough Opto Receiver

3.8 Flippers

Stern Left Flipper Assembly

4 Problems and Solutions

4.2 MPU boot issues

4.2.2 Repairing Alkaline Corrosion

Sega/Stern White Star boards are well known for issues with leaky batteries. This is because the Batteries are mounted on the top of the board - with plenty of board beneath it for the corrosion to affect.

Remember - Battery Acid is an Alkali - it needs to be neutralised before fixing any damage that was caused. Most commonly used is vinegar, since it is an acid, however not a strong one and one that will adversely affect the surrounding areas of the board.

4.3 Low +5VDC and Game Resets

The +5VDC for logic power is sourced from the 8VAC secondary windings on the transformer. The 8VAC is fed to the I/O Power Driver Board, and rectified via bridge rectifier, BRDG21. The rectified DC voltage is regulated via an LM338K adjustable voltage regulator. Logic voltage can be adjusted via R116 on the driver board, which is a 50 ohm adjustment potentiometer.

U413, which is located on the CPU / sound board next to the reset button, is a Dallas Maxim DS1232 monitoring chip. In theory, should the logic voltage dip to less than 5% or +4.75VDC, the DS1232 will force a reset of the CPU. However, it has been determined that most White Star board sets will not function properly below +4.85VDC.

If the voltage on the power I/O driver board is below the +4.85VDC threshold, adjustment can be made via the R116 adjustment pot, until a satisfactory voltage is achieved. The best location to measure the +5VDC is at the bottom leg of resistor R114. R114 is located in the vicinity of the R116 adjustment pot, and just below the +5VDC LED, L2. If a satisfactory voltage cannot be achieved, turn the game off. Remove connector J16, located above the LM338 regulator. Turn the game back on, and measure the +5V again. If a satisfactory voltage can be acquired with J16 disconnected, a board or component which uses the +5VDC is "dragging" it down. Turn the game off, and remove all 5V input connectors on all other boards at this time. Reconnect J16 again, and review the logic voltage on the I/O Power Driver board. Repeat the process of turning off the game, and reinstalling logic power connectors one at a time to determine the suspect board. Keep in mind that all opto switch receivers used throughout the game use the same +5VDC logic lines. If no other boards in the backbox appear to be suspect, an opto receiver board may be at fault.

Should the game start randomly resetting, the first course of action is to measure the +5VDC on the I/O Power Driver Board. If the logic voltage is within spec., measure the +5VDC on the CPU / sound board. Unfortunately, there are no definitive +5V test points on the CPU / sound board. The best location to measure the +5V is at pin 8 of U413. If the voltage drastically differs between the measurement of the I/O Power Driver Board and pin 8 of U413, turn the game off. Remove and reseat connections CN2 on the CPU / sound board and J16 on the I/O power driver board.

4.3.1 Game Resets with DMD Controller Board Connected

This may be a bit of an anomaly, but it is worth mentioning. If when the DMD controller board is connected without the data line ribbon cables, and the game continues to reset, replacement of BRDG21 may be required.

In one particular instance, a game was resetting continually with only the +5v / ground connection connected to the DMD controller board. If the board was not connected, the driver board would output ~+5VDC. If the DMD controller board was connected, the driver board's logic line would dip down to around +4.85VDC. Logically speaking, this type of symptom somewhat points to the DMD controller board having issue. However, the end result was replacement of BRDG21 per Stern tech support.

It is worth mentioning that the bridge rectifier did test correctly (using a DMM in diode test) both in circuit and out of circuit, but these tests were conducted while the bridge was not under load.

4.8 Sound problems

Basic operation (simplified) of the White Star CPU/Sound board audio part: The main CPU (U200) makes sound calls to the sound CPU (U6) which instructs the BSMT to play a certain sound. The BSMT fetches the required data (sound sample) from the ROM memory (U17-U21-U36-U37) and feeds the 16-bits wide parallel data to a conversion circuit which makes it serial data (shift register, U23-U24). The serial data is fed into a DAC (U26, Digital to Analogue Converter) that outputs to a pre-amplifier (U30, OPAMP). The output from the pre-amplifier is fed into the TDA2030A amplifiers at U101/U102 and sometimes U100 (some boards have 3 amplifiers, one for each speaker) and from there the audio signal goes to the speakers.

The sound section is quite reliable, the failure occuring most is a broken amplifier (TDA2030A).

Sound missing on one of the speakers: Most likely a broken amplifier (TDA2030A)

No sound at all: Check the voltages on the board. On the DC input connector CN2 there should be approx. +12V DC between pin 2 (GND) and pin 6 (+12V) and -12V between pin 2 (GND) and pin 3 (-12V), these voltages come from the Power Supply Board. On the board itself are two voltage regulators to convert the +12V and -12V to +5V and -5V for the pre-amplifiers, check these voltages by measuring between the ground (GND, test point) and U30 pin 8 for +5V, U30 pin 4 for -5V.

5 Game Specific Problems and Fixes

Lord Of The Rings

If your Balrog stops registering hits, a little checking will sort it out. The mini microswitch with a roller arm used to register hits may need adjusting. Known past problems are a flaky or bad switch, and / or wiring. The Balrog moves in a way that wires can break inside where you can't see readily them. It's easy to check the switch and wires with a meter. The wires push into an IDC connector nearby, so be sure they are pushed in tight.

6 Repair Logs

Did you do a repair? Log it here as a possible solution for others.