Bally/Stern MPU - PART ONE, Stage One

[Homepin]

I have now finalised the daughter board kit that replaces the obsolete 9602 oscillator IC. Instructions are written and an initial test board has been assembled and it works perfectly! This project was a result of the Bally MPU-35 replacement board kit. It was soon discovered that some parts, such as the 9602 IC were simply unavailable. There are a few about, member Skybeaux has some available, but I expect that they will be snapped up by people assembling the Bally board kit when it is finally finished (expected to be in about 2 weeks from now).

Estimated price INCLUDING pack & post AU/NZ is $20 or $15 when purchased with the MPU kit.

Ideally you would try to track one down when building the kit MPU but at a worst case this little add-on board neatly solves the problem.

Here is what is supplied in this kit:



Here it is installed on a Bally MPU for tests:



and here are the CRO shots of the two outputs generated by this board.
Note the frequency is about 450khz - specs for this Bally board show "approx 500khz" so I'm happy with this.

[beaky]

That's a nice little add on / replacement pcb. There are not many things worse than designing a pcb then finding out that a component is no longer available. 
I have had this happen to me before, I was told by the supplier at the time they had thousands in stock, then when i went to order the part I was told they only had 10 left and they were obsolete.
fortunately the company that was making the boards for me had a hiccup with the order that was in front of mine and were running 2 days behind so i had time to edit the pcb layout for a replacement component.   

[Homepin]

Yes, that's why I insist on putting parts into stock BEFORE I make PCBs - it's too easy to come unstuck. In this instance we were well aware of the obsolete staus of this part so we went about making sure that the board could be built EXACTLY like the original if the builder had the part BUT if not this board fixes the problem without modifying the main PCB.

[Caveoftreasures]

Mike, can u list what machines this unit would be suited for, as an example. 
 

[studley67]

 $.$will this new system work in old sterns?

[ajlaird]

Nice work, really enjoying these threads!

[Homepin]

In response to Bretts question about machine compatibility here is a list of machines this board will drop straight into:

1977 to 1985

Bally MPU AS-2517-17

Freedom, Night Rider, Evel Knievel, Eight Ball
Power Play, Mata Hari, Strikes and Spares
Black Jack.

Bally MPU AS-2517-35

Lost World, Six Million Dollar Man, Playboy, Voltan
Supersonic, Star Trek, Paragon, Harlem Globetrotters
Dolly Parton, Kiss, Future Spa, Space Invaders
Nitro Groundshaker, Silverball Mania, Rolling Stones
Mystic, Hotdoggin', Viking, Skateball, Frontier
Xenon, Flash Gordon, Eight Ball Deluxe, Fireball II
Embryon, Fathom, Medusa, Centaur, Elektra, Vector
Spectrum, Speakeasy, Rapid Fire

Bally MPU AS-2518-133

Granny and the Gators, Mr & Mrs Pacman, Baby Pacman
Eight Ball Deluxe Limited Edition, BMX, Centaur II
Goldball, Grand Slam, Midnight Marauders, X's & O's
Kings of Steel, Black Pyramid, Spy Hunter
Eight Ball Deluxe Classic, Fireball Classic, Cybernaut

Stern MPU-100

Pinball, Stingray, Stars, Memory Lane, Lectronamo
Wildfyre, Nugent, Dracula, Hot Hand, Magic
Cosmic Princess (kit)

A further development at Stern resulted in the "-200" board. This Stern MPU used 2 X 5101 RAM so I am unsure about the compatibility
with the Homepin kit MPU? This requires more investigation and I welcome feedback on this.

Stern MPU-200

Meteor, Galaxy, Ali, Big Game, Seawitch, Cheetah, Quicksilver
Stargazer, Nineball, Iron Maiden, Viper, Dragonfist, Flight 2000
Free Fall, Lightning, Split Second, Catacomb, Orbitor One