Repair Williams systhem 3/4/6/7 sound card

In Williams pinballs of types 3 to 7, 2 types of sound cards have been used. The early models system 3 and 4 do not have "speech", which started with Gorgar. The "speech" is created on a seperate board which is connected to the soud card. (see picture).

The type 2 card with on the left its "speech" card.

Type 1 sound card.

The sound card is an independent board which has its own power supply and has an own cpu chip. Some outputs of the driver board go to the sound board and connect them to ground (using connector J3) and will trigger a sound or speech sample.

The sound card has its own CPU chip, a RAM chip, ROM or EPROM and a PIA chip. We'll test all of these. Other parts are the power supply and sound amplifier which is one IC: TDA2002. These first versions of sound boards are very simple and easy to repair.

You can start the internal self test of the sound board by pushing the little button, all sounds will run one by one...

From type 1 of the sound board there are models which are almost identical, the one type has one fuse, the other has two. These fuses secure the 10 volt AC when it enters the sound card. Another detail: the sound card with one fuse has not always a connector J4 to connect the external volume pot. (in the cabinet), here the volume pot. is on the board .

Compare with the picture above, this card has only one fuse and J4 is missing..

I would recommend that you read the excellent repair manual for williams games 3/to 7 at where a lot more details about the sound card can be found....

Before we use the test eprom, first test the power supply. The connectors are the same for all types of boards.

On connector J1 pins 1+2 and 8+9 with in the middle pins 5+6 receive two times 10 to 12 volt AC from the transformer. It passes one or two fuses to a bridge rectifier which converts this to + and - 12 volt .. +12 goes to the entry of the voltage regulator for 5 volt the 7805, on its output we find 5 volts.

Schematics from these boards are available here:

Old type without speech...

<Jumper setting for this board ( set the jumpers as on the image) ...

Sound card type 2....

Jumper setting of this board , depending the game ...

You can check the voltages leaving the board in the pinball . Type 1 boards....on C29 +12 volt, on C30 - 12 volt and at the output of 7805 = C27 = + 5 volt ... On type 2 boards it's best to measure at the 3 capacitors at the bottom right: C25, C26, C27 which give resp. +5, -12, and +12.

If one of these is missing then search the power supply, fuses, bridge rectifier. If you do have +12 and no +5 then check or replace the 7805..

Are the power supplys ok and the sound card doesn't work, then check if the amplifier TDA2002 works. Loosen the card but leave it connected. Touch with your finger under the connections of TDA2002, you should hear a humming sound. If this isn't then there's something wrong with the TDA2002. Don't forget to turn up the volume Now we know the power supply and amplifier work, it's time to remove the board and install it on the work bench.

Sound card on the work bench.

The usual suspects are bad soldering, especially at the connector pins and the TDA2002. Also chip sockets shouldn't be trusted anymore and it's best to see if there's still a good connection. Another remark: older pinballs will only produce one sound instead of all sounds, and on two models the test button doesn't work at all (Disco Fever and Phoenix). Further you can have a broken speaker or a broken or closed volume pot. To test this we connect another speaker and we'll bridge the volume by connecting the middle pin with the one which is not connected to ground.

The power supply should be 10 to 12 volt AC, so you need a small transfo, or it can be DC +/-12 volt which is the easiest. You probably have a power supply from a computer which you can use. You can connect this DC power instead of AC it doesn't matter..

Connect ground to pins 5+6 of connector J1 and 2x 12volt AC or +12 and -12 DC on pin 1+2 and 8+9. If you work with DC then ground is pins 5+6 and the + and - 12 can be connected to 1+2 and 8+9. To which pair you connect the +12 or -12 volts doesn't matter, the bridge rectifier which rectifies the AC will bring the DC to the correct places... Connect a small speaker to pins 2 and 3 of connector J2. you connect pins 1 and 2 of connector J4 together by making a temporary jumper so the volume pot. doesn't matter. Remove the speech card if its present and make a wire bridge W1. Check the picture for details...

The blue arrow shows the jumper over the volume switch. J3 has the speaker connected and the red arrow shows W1 so the card works without the speech board. In the picture you see a special connector I made for power supply.


You can download my test-eprom here, program into a 2716 eprom............


If the power supply is ready and speaker attached, with the test eprom in place of the usual sound rom we can start. Connect a control-led to pin 15 of cpu chip U9. This control led is a led with resistor in series, check my previous tests on this website for more information how to make this.

This is the test led (in series with a 1200 ohm resistor ) to connect to addres line 6. The red handle goes to +5volt, green handle to pin 15 of cpu chip IC9.

Put some shrink tube over the connections, to check if the led is connected ok, connect the green side to ground and it should light (if not, switch connections).

The test

When you turn the power on, the led should start to flash in rhytm.

Attention, Both dipswitches or the single switch must be at " off" position.

If it's working, you can check the outputs of the PIA chip IC10 (IC3 type1) which go up and down between 5 and 0 volt. Is there one missing then unsolder this pin and bend it up or cut the trace. Is the output is ok now then there is a short on the pcb. There are only 3 possible chips connected IC13, IC5 and IC6, (IC6 IC8, IC9 type1). Check the schematics to see which chip is connected to this output. If the output of the pai is stil bad then the PIA is broken.

If the test led doesn't light in rhytm then something substantial is broken on the cpu chip or the selection of the test eprom.

Control led doesn't flash..

We'll first measure the signals on the cpu chip (6802/6808). Remove the test eprom and connect power without a sound rom or test rom. The board will start a NOP (non operations) and pass all addresses from 00000000 to FFFFFFFF. Here is what you should measure with a universal voltmeter ....

Pins: 2, 3, 4, 6, 8, 38 = + 5volt

Pins: 5 ,34, 40 = + 4 volt

Pins: 9 to 20 , also 22, 23, 24, 25, 37 = + 2 volt .

Pins: 21, 26, 27, 28, 29, 33, 36 = 0 volt.

Pins: 38 and 39 get a clock signal which measures 0,2 volt with a universal voltmeter.

If a voltages is wrong , check if its an output or input signal. If it's an output like an address line then the cpu IC is broken. If it's an input signal then check the schematics to see where it comes from.

Pin 40 ( reset) gets 5 volt through a delay circuit of 2 transistors. If it's missing then replace the transistors..

This method works for all three types of sound cards.

Memory test

If the test is running well and all PIA outputs are ok, we can test memory chip 6810, which only exists on cards of the second (square) type. This test doesn't have to be done on cards of type 1

Start the memory test by pushing during the PIA test the small pushbutton which is on the right top of the board. If the test is ok the the led will start blinking again. If the memory is bad then the led will stay dimmed, but the test will keep on running and testing the memory until it's found to be good. This way it is possible for us to test the signals which should exist on this chip, these are:

Pins: 1, 14, 15 = 0 volt

Pins: 2 to 9 also 13, 20, 21, 22, 23 = 2 volt

Pins: 10 and 24 = 5 volt

Pins: 11, 12, 16 = 3 volt

Pins: 17 and 19 = 0,5 volt

Signals which differ a lot you'll have to investigate where they come from, or why they are missing. Usually the signals will be ok and the memory chip itself will be broken.

"Speech" card

Here you find the schematics for the speech card ......

Start with a working sound card. Remove the temporary jumpers W1 and on the volume switch connector J4. If you don't get any sound when you connect the speech board then you know the problem exists on that board..

Do you have sounds but no speech then you can be sure the mixer chip IC2 is ok. If you can't hear anything then it's almost sure IC2 is broken.

IC3 should only be replaced as a last resort, this is the speech amplifier. The entry and output passes through condensors which offers protection against voltage spikes.

It's best to start checking the roms and if their contents are still ok, also check all sockets. Remember these eproms are 2532 type, whilst the sound eprom is always a 2716.

If there's no change, then only IC1 is left.


If you have a new board or board from another Williams pinball , check if the straps/jumpers on the card match these of the original board. Different setups are possible depending on type of eprom used.

Here you find a list of the straps for the different types of boards. The straps are for a type 2 board !

W2,5,7,9,10,15 with a rom type 2716 for Gorgar, Blackout, Firepower, Black Knight, Jungle Lord, and Pharaoh.

W1,2,5,7,9,10,15 with a rom 2716 for Defender, Solar Fire, Barracora, Hyperball, Stargate, Cosmic Gunfight, Varkon, Time Fantasy.

W1,3,4,5,7,10,15 for rom 2532 on Joust.

On the schematics of the type 1 board you find at the top the strappings for this type of board.


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