Williams Pinball No Sound: Finding the Fault on System 3 to 7

The game boots, the displays count up, the flippers snap, the ball kicks out — and the whole thing plays in silence.

No sound is one of the most-repeated questions on the Williams forums, and one of the most misdiagnosed: the sound board is the obvious suspect, so that is where people start. On a System 3 to 7 game the fault is very often somewhere else, and almost always cheaper.

The short version: the Williams sound board is a self-contained computer with its own power supply and its own fuses, on the board itself. Check those fuses and rails first, press the board's test button to split the problem in two, then check whether anything is actually asking it to play. Only then look at chips — and nothing on a Williams sound board is unobtainable.

Contents

• What should your game sound like?
• Which sound board do you have?
• It has its own power supply
• Press the board's test button
• When nobody is asking it to play
• The parts that actually fail
• Sound, but no speech
• Repair or replace?
• FAQ
• Sources

What should your game sound like?

Two minutes here saves an evening, because a game can behave perfectly and still sound broken.

Hot Tip (1977) and Lucky Seven (1978) have no sound board at all. They use chimes — real metal chime units fired by coils — so a quiet one means a chime coil or a driver transistor.

The second trap: on the earliest electronic boards, World Cup through Pokerino, the game is meant to be silent between events. The background tone that rises in pitch with your score did not arrive until Flash, so a Phoenix sitting quiet over an empty playfield is not faulty.

Which sound board do you have?

Advice that fits one of these boards is wrong for another. Identify yours before you buy a part.

Board	Games	Behaviour	Speech?
None — chimes	Hot Tip, Lucky Seven	Mechanical chime units fired like solenoids	No
First-generation board	World Cup through Pokerino	Sound on scoring events only; silent otherwise	No
Type 1 board	Flash through Algar	Adds continuous background sound, pitch rising with score	No
Type 2 board — square; D-8224, silkscreened 1C-2001-145 or 1C-2001-146	Gorgar onwards, to the end of System 7	Has a connector for an optional speech daughter board	On talking games

The Type 2 board is the one most owners meet. On it: a 6808 processor at IC9, a 6821 PIA at IC10, a 6810 RAM at IC11, the game's sound EPROM (a 2716) at IC12, and an MC1408 DAC at IC13 feeding a TDA2002 amplifier. Williams used the same board in its video games, which is why spares and cap kits are easy to find. Later System 7 games that never talked, from Solar Fire on, use it with the speech connector left off.

One practical note: System 3 and most System 4 games hide the sound board in the lower cabinet, not the backbox. If you opened the head and found no sound board, look in the cabinet before you panic.

It has its own power supply

This is the fact most often missed: the sound board has its own rectifier, its own regulation and its own fuses, mounted on the board. It does not run off the main supply — so if the game plays faultlessly and simply has no audio, do not start modifying the main power supply. Check instead:

• F1 on the board (Systems 3 to 7), plus F2 on Systems 4 to 7. Both are 4 A slow blow. Some System 3 schematics mislabel F1 as 2 A, so trust the fuse's rating over the print.
• The three rails: +5 V, +12 V and −12 V. Meter all three. A missing negative rail takes the audio stage with it while the digital half of the board carries on as though nothing happened.
• BR1, the bridge rectifier. A tired bridge is a common cause of blown sound fuses; four 1N5401 diodes are an accepted substitute.

Be suspicious of a rail that is merely present. One at half value usually means a failed electrolytic, diode or resistor in that leg — cheap to find, and exactly the fault that sends people shopping for boards. If the game is eating fuses elsewhere too, start with our guide to finding the short behind blown fuses, and check the backbox ground strap is on its wing nut and tight while the head is open.

Press the board's test button

Most Williams sound boards of this era carry a small push-button that plays a sound directly, without the game's CPU. It splits the problem in half:

• You hear something. Board, amplifier and speaker are alive. The fault is upstream, in whatever should be asking the board to play.
• You hear nothing. The fault is on the board or after it — back to fuses, rails, speaker wiring, then chips.

Remember that these games do not self-test at power-on — that only runs when you press the test button on the CPU board — so silence at switch-on is not a diagnostic result.

On System 7 there is more to work with. Enter diagnostics and advance past the display test to reach test 00, the sound test: the game shows each sound number in the ball-in-play window and plays it. If the coin door buttons will not get you into diagnostics at all, check CPU connector 1J4 — unseated or with cracked header pins, it kills those buttons and locks you out. Our guide to the System 7 CPU LED diagnostic codes covers the rest.

When nobody is asking it to play

The sound board does not decide what to play. Something has to ask it, and how changed with System 7.

Systems 3 to 6: the game triggers sounds through the driver board, using solenoid outputs 9 to 13 — the same transistors that fire coils. A dead driver transistor on one of those outputs silences a perfectly healthy sound board, and no work on the sound board will fix it. Other coil faults alongside the silence are a strong hint. Our overview of pinball electronics explains how MPU, driver and sound boards divide the work.

System 7: Williams added a dedicated sound PIA on the CPU board, freeing coils 9 to 13 for playfield use. Sound and coil faults stop being tangled together, at the cost of a new failure point on the CPU board.

Either way, the select lines are the quiet killer. A Laser Ball owner on Pinball Nirvana had the board's test button working — so the board was clearly alive — yet grounding the select inputs by hand produced nothing. The cause was a failed buffer inside IC8 on the select-input path, found only after a PIA, the ROM and IC4 had all been replaced.

Steal that trick: with the board powered, briefly ground the select inputs one at a time and listen. Sounds you can trigger by hand but not in play puts the fault upstream; nothing at all, with good rails, puts it on the board. Those lines run through forty-year-old housings, so read our piece on burnt connectors and the faults they cause first.

The parts that actually fail

Electrolytic capacitors

Start here. These are forty-year-old audio circuits, and dried-out electrolytics show up as audio faults before anywhere else in the machine. Cap kits for the D-8224 are nine axial capacitors and widely sold. Intermittent rather than absolute silence? Suspect capacitors before chips, every time — as you should for silence that comes and goes with power cycles.

The MC1408 DAC at IC13

This one eats weekends. A Jungle Lord owner on Pinside chased barely-audible audio through blown fuses, a bad bridge rectifier, two new TDA2002 amplifiers and a round of recapping, all with good rails, before logic-probe readings against a working board fingered the MC1408 DAC at IC13. Replacing it restored normal volume; a DAC0808 is a compatible substitute and easier to buy. DAC failures usually present as all-or-nothing rather than low volume, which is why this took so long to find.

The amplifier, ROMs and sockets

The TDA2002 is exposed in a way the rest of the board is not. In one documented Black Knight case, a cross-connected black-and-white connector energised a flipper through the amplifier IC and destroyed it — so find what killed yours before fitting a new one. Sound ROMs are game-specific: a wrong ROM gives wrong sounds, not silence, while static instead of sound usually points at the ROM or blackened legs in a tired socket. Sounds firing at the wrong moment are nearly always the select lines, where corroded pins scramble which sound is requested rather than stopping the request.

Sound, but no speech

Speech is a separate daughter board plugging onto the Type 2 board, with its own ROMs (2532 EPROMs on Systems 6 and 7) and its own decoder. That separation is why you can have full effects and no voice.

First confirm your game ever spoke. Speech was fitted to Gorgar, Firepower, Blackout, Alien Poker, Black Knight, Jungle Lord and Pharaoh. If your game is not on that list, it never talked.

If it should talk and does not, in order:

• The speech ROMs and their sockets. A Blackout owner with sounds but no speech proved it by swapping ROM sets between two machines: Gorgar's ROMs worked in the Blackout boards, but the Blackout ROMs failed in both. New speech ROMs fixed the game.
• The sound board's dip switches, which select sound-only or sound-plus-speech. A dirty contact does a convincing impression of a dead speech board.
• The voice board's balance pot — centre it, and try the game with the voice board unplugged to see whether the symptom changes.
• Then the decoder, an HC-55516 CVSD chip. Substitutes exist, with a real caveat: the faster HC-55564 works in several talking games but is not reliable in Black Knight or Alien Poker, where the software clocks the decoder through the PIA and timing matters.

Repair or replace?

Here is the honest answer, and it is a good one: repair it.

We do not sell a Williams sound board, so we have nothing to gain by saying so — but a Type 2 board has no unobtainable parts. The 6808, 6821, 6810, MC1408, TDA2002 and HC-55516 are all still buyable or substitutable, cap kits are off the shelf, and because the board was used in Williams video games too, donors are plentiful. That is a very different situation from a Gottlieb board with a dead mask-programmed 6530, which is a hunt rather than a shopping trip; our System 80 no-sound guide covers that side.

Where replacement comes in is the other board in this story: if your silence traces back to the driver board's sound outputs, or the sound PIA on a System 7 CPU board, this was never a sound board problem.

The WillFA7 is a 2-in-1 replacement for the MPU and driver boards across Williams System 3 to 7. Two honest caveats: it does not replace your sound board, so it will not fix a fault living there, and if your diagnosis has not pointed at the MPU or driver board, it is not the part you need. Our write-up of repairing a Williams Flash with a WillFA7 shows the job in practice, the System 3 to 7 replacement board guide covers how to choose, and our comparison of repairing versus replacing sets out the arithmetic. We test boards before they ship and support them afterwards.

Either way, keep the original sound board. One with a dead DAC is a good winter project once the game plays again.

FAQ

Why does my Williams pinball machine have no sound?

Start with the fuses on the sound board itself — F1, plus F2 on Systems 4 to 7 — because the board has its own power supply, separate from the machine's. Then meter the +5 V, +12 V and −12 V rails. Then press the board's own test button. Only after all three does the board itself become the main suspect.

Where is the sound board fuse on a Williams System 3 to 7?

On the sound board, not in the main fuse panel. Systems 3 to 7 have F1; Systems 4 to 7 add F2. Both are 4 A slow blow. Some System 3 schematics print F1 as 2 A, a known error — go by the fuse's rating.

How do I test a Williams sound board on its own?

Press the small test button on the board, which plays a sound without involving the CPU. If you hear it, board, amplifier and speaker are fine and the fault is upstream. You can also briefly ground the sound-select inputs one at a time to trigger sounds by hand.

My Williams game has sounds but no speech. What is wrong?

Check that your game ever had speech — only Gorgar, Firepower, Blackout, Alien Poker, Black Knight, Jungle Lord and Pharaoh were fitted with it. If it should talk, suspect the speech ROMs and their sockets first, then the sound board dip switches, then the HC-55516 decoder on the speech board.

Can the driver board cause no sound on a Williams pinball?

Yes, on Systems 3 to 6. The game triggers the sound board through the driver board's solenoid outputs 9 to 13 — the same transistors that fire coils — so a failed output there silences a working sound board. System 7 uses a dedicated sound PIA on the CPU board instead.

Is it worth repairing a Williams System 6 or 7 sound board?

Usually yes. Nothing on it is unobtainable: the 6808, 6821, 6810, MC1408 DAC, TDA2002 amplifier and HC-55516 decoder are all still available or have substitutes, and capacitor kits are sold off the shelf. Most no-sound faults here are a fuse, a rail, a capacitor or a connector.

Sources

• pinrepair.com: Williams System 3-7 — board generations, fuses, sound triggering
• pinrepair.com: Williams System 3-7 — diagnostics, test 00, connector 1J4
• FirePower Pinball: Type 1 and Type 2 sound board part numbers and IC locations
• flippers.info: Williams System 3-6 — sound board architecture and location
• Pinball Nirvana: Laser Ball no sound — solved, failed buffer at IC8
• Pinside: System 6/7 low volume — solved, MC1408 DAC
• Pinside: System 6 sounds but no speech — solved, speech ROMs
• Pinside: HC-55516 versus HC-55564 speech decoders
• Arcade Parts and Repair: HC-55516 CVSD decoder and the games that use it
• Arcade Parts and Repair: Williams D-8224 sound PCB capacitor kit

Silent Williams and not sure what your meter is telling you? Send us the game, the board markings and your readings on the three rails. Our technical support is free, before and after any purchase — including when the answer turns out to be a 4 A fuse on the sound board.