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RECEL CPU boards

History of the RECEL Pinballs Here

Thanks to a message left by one of our nice visitors on this site, we recently discovered that Gottlieb was not the only manufacturer having used PPS4 spider chips for their CPU board. RECEL also used a similar architecture. On the link above is collected precious data concerning these machines.

There is very little information on these machines. In particular the datasheet for the 11696 is nowhere to be found. If you have a datasheet for this chip and if you want to help, please contact us Here and we will send you our email address to get this precious data and check if what we inferred from our experimentation is exact.

At the moment, the documentation on this system is Here

From the site, we could find the complete schematic of the Master Unit, which is of great help to understand this system. Master board complete schematic

From the site, you might also find precious information about Recel system3, including a replacement board for the MPU. Master board complete schematic

On the Mame Github Here we picked also the following information:

Summary of IOL codes

IOL code #U Device Type Role
b1101 (0xD) B3 11696 PIO
b0100 (0x4) B1 A1761-13 Access NVRAM HM6508+few output control
b0010 (0x2) B2 A1762-13 16 outtput control
b1111 (0xF) B5 10788PA Display control

Retrieving code of Recel pinball

(2023-11). Thanks to Paulo, one of our nice visitors on this site, who agreed to lend us the two spiders of RECEL (A2361&A2362) where the code resides, we eventually were able to read the program that runs RECEL pinballs. As an easter egg, Paulo also sent us a game eprom (for screech) we also read (1702 eprom from 1972, weird chip) and archived on github. This material is now (for the first time) available to the community.

Binaries of Recel Here

or use the command: git clone

Commented code disassembly Here

Eduardo, from, later (2023-12) sent us another variant for these 2 chips, namely A1761-14 and A1762-14 (variant 14 instead of 13). We returned him the set as promised after a few days, the time for us to read their contents. We read the 14 variant and found the exact same contents as for the previous 13 variant.

Therefore we can safely assert that variant 13 and 14 of these chips are strictly identical.

Repair of a Recel System III


Now that we have everything to make clones of A1761s and A1762s we have all we need to repair any Recel System III.

There are few situations where we are facing a dead end (up to now, but things may change).

If the processor is dead, the only solution is to find a good one in replacement. We don't know how to clone it yet. We expect to be able to very soon.

If the 10788 is dead, you can use one of our 10788 clone from here

If the 11696 is dead, the only solution is to find a good one in replacement. We don't know how to clone it yet. The problem here is that it is impossible to find a datasheet for this GPIO. Cloning such a device is theoritically easy, but it is not realistic trying to make clones of it since we don't know in details of how it is controlled.

If you identified that your problem comes from a BIC, an A1761 or an A1762, then we have a solution for you.

Therefore, if you want to try our solution, as a guinea pig for the community sake, we offer a 50% rebate to the first candidate. No risk for you. If it does not work, you return the clone, you would have paid only for the shipment. If it does work, you have a running machine for almost nothing. If you are interested, please contact us. Here and explain your problematic. We will reply quickly and exchange by email to see if we estimate there is a good chance to solve the problem.

How it will work

If the problem is related to one A17, or both of them, the only thing we have to do is to replace one or both by one or two clones, just as we do for Gottlieb system I.

If the problem is related to one BIC, or both of them, this is where the beauty of our solution resides: BICs are only used for interfacing the eprom. By integrating the eprom contents right in our clone, we will interface the 256 bytes of the eprom internally. All you have to do is replacing any A17 by its clone, and pulling out the 2 BICS to prevent bus contention. And that's it. One single clone will play the role of the A17+the 2 BICS+the eprom. The code in ROM is unchanged!

Ready to check it out?

System 3 sound section

We also made a model of the System 3 sound section. More infos Here

Resuscitation of a FairFight

This video shows a working Fair fight, which implements 2 A17 clones: