Thursday, 5 February 2015

Testing the Squawk & Talk Sound Board Redesign

The first proto boards arrived from the manufacture just before Christmas, so i set about assembling one to test the design and iron out any issues /errors. I have documented the assembly process below with videos and descriptions of each stage.

Update 1

First part of the board is assembled and tested. I am assembling the digital section in stages, following the diagnostic led sets of parts to check everything is working ok. I have assembled upto both pia chips so far and have a flicker and 3 flashes   It was great to see that led start blinking!

Below is a quick video showing the status led blinking at power up. Note that the first flicker is now more like a flash as i am using a reset chip ic.

Next i will be assembling the ay sound generator section, then the speech section and then the op amp, filtering and power amp sections

Update 2

Update on development. All five flashes are now working with the speech chip section installed. Moved on to the amp side and populated the main amp and speech pre-amp/filtering section. Also added my Elektra roms, tested the jumper dipswitch configs and all working from the test button. 

After christmas and holiday break i will be moving onto the final population of the dac and sound amp section and the data input section.

Update 3

Back on with assembling the remaining parts on the s&t sound board now christmas is over.

A question for interested people: A friend of mine mentioned the idea of adding into the board the centaur reverb circuitry as an optional extra. The idea here would be to use the holtek guitar effects chip replacement circuit that can be bought separately and add it into the design as an optional population section. The circuitry would be enabled or disabled with dipswitches. This would mean any game could have the echoey sounds  

Please let me know what you think

Update 4

Update: New video. All sections are now tested and working (sound amp & filtering, dac and data input). The first proto board is now fully assembled and it all went rather well   A few things to alter for the next revision, but its time now to try it in a few different games. Very happy with the sound quality so far and am looking at the reverb/echo addition to. I think it's the best i've ever heard these games sound  

New video of the board running in my partially complete Elektra restoration here:

The self test now includes the sound effect as well as all the speech calls. I also tried out the mpu to sound board data flow from in game. There are some great 80s sounds that this board can generate  

Update 5

Update: New video. I created a test echo/reverb circuit and connected upto to my proto board. All tested very nicely. Video here of my Elektra with echo! Very cool to hear this! I set the reverb pretty high for testing.

I'm now finalising the changes for the production board and building another proto board to test in a few other games/locations. I'm thinking of creating the echo board as a separate plug on daughter card option for the J2 connector (rhs) instead of additional parts on the main board. This means it can be easily plugged onto boards in the future, require no additional wiring and will keep costs down for the main board. I will be looking to create this daughter board as an optional extra after the first run of standard boards is under way.

Update 6

Some new videos of additional testing with the proto boards in a friends centaur yesterday. Working really nicely

Sound Board Test

Game Play

Pre-Ordering is now open for the first run of 25. The cost for an assembled and tested standard board will be £149 inc. VAT plus postage to your country. The pre-order process will run like my other board and mod projects with 50% upfront and then the remaining 50% once your board is ready to send. I am aiming to have the boards ready within 2 months, all being well.

Please contact me now if you'd like to get in on the first run. Thanks, or click here

You are also welcome to purchase the blank pcb or a kit from me if you want to assemble it yourself.

The summary of updates for my board are:

- Reduced component count
- Test point pads for common signals and voltages
- Leds for power voltages and diagnostic led
- Improved and simplified reset section
- On board reset button
- Dip switch config for rom settings
- Fully compatible with all stock roms
- Dip switch config for inclusion of sound generator ic
- Expanded J2 connector to allow future plug on daughter cards such as echo/reverb board.
- Option via J2 for external amp hook up and multiple speaker usage
- Higher power amp on board for stock speaker connection
- Socketed ICs
- Plate through design

The board is designed to work in the following games:

Beat The Clock
Centaur II
Eight Ball Champ
Eight Ball Deluxe
Eight Ball Deluxe Limited Edition
Fireball II
Flash Gordon
Mr. & Mrs. Pac-Man
Rapid Fire

As normal, visit my full website over at or contact me directly at or tweet @mypinballs to say hi