1st Generation CPU Boards

This board houses the CPU chip, game ROMs, game RAM, CMOS RAM with battery, and the circuitry for the switch matrix. It has connectors for power, switch matrix send/return lines, and ribbon cables to the driver board and displays. Unlike most other solid state pinball manufacturers, Zaccaria used a Signetics 2650A CPU chip for their boards, which you can see as the large (40 pin) chip in the centre of the board.

Click on the thumbnail above for a larger picture of a Zaccaria CPU board. This one has already had the (leaking) battery removed and the damaged area cleaned and neutralized.


The major areas of this board are:

ROMs and ROM Jumpers
Top row of five chips. All 1st generation game use five ROMs. The earliest games used five 2708 EPROMs, though they later expanded the board to support up to two 2716 and three 2708 EPROMs. The jumpers are next to the ROM sockets, and are used to select the size and type of the ROM chips installed. The correct jumper settings for the games can be found on the documentation page here.
To the right of the ROM chips. There are a 5101 (in socket) and a 2101 RAM chip. In addition to the ROMs, especially ROM #5, these are often damaged when the battery leaks, and 5101 CMOS chips are notoriously fragile and prone to failure from electrostatic discharge (ESD) and age. Replacement 5101 chips can be obtained from Ed at Great Plains Electronics.
Top centre of the board are the pads where the battery is mounted. On the board pictured, the battery has been removed, but the silkscreen rectangle above ROMs #4 and #5 shows its prior location. See below for more battery information.
Below the ROM chips, the large IC in the centre of the board is the Signetics 2650A CPU. The one pictured is in a white ceramic package, but black plastic package ICs are common as well.
Connector CN11 (Displays)
On the left edge of the board. The ribbon cable to the display boards connects here.
Connector CN10 (Driver Board)
On the bottom edge of the board. The ribbon cable to the driver board connects here.
Connector CN7 (Power)
On the right edge of the board.
1 170VDC
2 Ground
3 Not Used
4 12VDC (VDD)
5 5VDC (VCC)
6 -5VDC (VGG)
Connector CN8 (Switch Matrix - Columns)
On the right edge of the board, under the Power connector.
Connector CN9 (Switch Matrix - Rows)
On the right edge of the board, under the Columns connector.
Setup Enable Switch
In order to enter setup mode and set the default pricing and operator settings used by the game, this pushbutton switch must be pressed, then the "Test Advance" switch on the coin door will advance in to the settings.


The biggest worry with a Zaccaria CPU board is the NiCd battery pack used to maintain the CMOS memory when the game is powered off. This battery pack is mounted at the top of the circuit board, in the center. If it starts to leak, the battery fluid runs down the board and ruins every component in its path. If you have a non-working Zaccaria game, this is the first thing to look for. If yours is working and hasn't leaked, PLEASE get the battery off the board and either use a 1F memory backup capacitor, or mount a remote battery immediately. If the battery has leaked, Clay's web site has a good recovery procedure for dealing with the corrosion and damage. After cleaning up and neutralizing the leaked fluid, remove and replace all components that were touched by the battery fluid, and all sockets on the board. Inspect the connectors and ribbon cables for signs of corrosion and replace as necessary.

To replace the original battery, a 1F 5.5V computer memory backup capacitor like Jameco P/N 142957 or Mouser P/N 555-1.0Z5.5 can be mounted on the CPU board in place of the battery pack and short leads used to connect it to the battery (+) and (-) traces, or a fly lead can be connected where the battery used to be and used to reach a remote battery pack.

To mount a remote battery pack, cut two wires to about 16" long, and solder them to the battery (+) and (-) pads. The other end I solder to a .100" two-pin connector snipped from an old PC floppy drive controller. I add a drop of JB Weld two part epoxy, then heat-shrink the connector, forming a small plug that is just the right size to connect a Radio Shack rechargable portable phone battery (Part #23-197, 3.6V, 350mAh, NiCad). Mount the battery on the left wall of the backbox with a velcro strap stapled to the wood, and you should never have to worry about battery leakage again. Replace the battery every few years, just to be on the safe side.

Test Points

There are many logic test points on the CPU board:

Test Point Signal Purpose
TP1 VBB +5V Battery
TP2 VDD CN7: +12
TP3 VCC CN7: +5
TP4 GND CN7: Ground
TP5 VGG CN7: -5V
TP7 Signal CPU: FLAG
TP10 Signal CPU: OPREQ
TP11 Signal CPU: M/IO
TP12 Signal CPU: WRP
TP13 Signal CPU: W/R
TP17 Signal Interrupt Generator Output
TP18 Signal RUN
TP19 Signal Switch Matrix Row 1
TP20 Signal Switch Matrix Column 0
TP21 Signal CN10/CN11: RUN

These are useful if the game is not running, or to confirm that it is running with the displays disconnected.

Revisions and Compatibility

Four revisions of Zaccaria CPU boards for the games are covered by this document; part numbers 1B1110, 1B1110/0, 1B1110/1 and 1B1111/1a.

The 1B1110 is the original design for this board. It supports only five 2708 EPROMs for ROMs, and will work only in Winter Sports, House Of Diamonds, Shooting the Rapids, and Future World.

The 1B1110/0 is the first update to the board. Used on Hot Wheels, Fire Mountain, and Star God, there were two major changes, the first of which was adding support for 2K ROMs (2716 or CN13503N) at positions 1 and 3, although it appears that the changes to allow a 2K ROM at ROM #3 were incomplete, so that only a 2708 will work in this position. As part of the changes to support the larger ROMs, to make the board backward compatible with the 1B1110, jumpers J17 and J18 were added. J17 and J18 control where in the address space ROM2 appears by changing its Chip Select from IC11 output line 1 to IC11 output line 7. The other change is a "clear CMOS RAM" feature where the game will ignore and clear the contents of the 5101 if it is powered up with TP19 (Switch Matrix Row 1) connected to TP20 (Switch Matrix Column 0). This was likely to deal with problems caused by flakey 5101 CMOS RAM chips and failing batteries that could cause the contents of the 5101 to be corrupted; the earlier games could simply crash or even fail to boot.

The 1B1110/1 is the second update to the board. Used on Space Shuttle and Earth Wind Fire, this board introduced Switch Matrix Row 7. The 1B1110 and 1B1110/0 do not have CN9 pin 9 connected to anything. The 1B1110/1 has CN9 pin 9 connected to IC26 pin 15. This, and the previously unused Switch Matrix Row 6, are used to support the 1B1149 "Flipper Programming Board" (see below).

Finally, the 1B1110/1a was the last update to this board. It does not appear to have been manufactured, but designates a factory modification to the 1B1110/1 design. This board was used only for Locomotion, their last 1st generation game. To fully support having a 2K ROM at position 3, they cut the trace at IC11 pin 6 (which used to connect to IC39 pin 12) and connected it with a jumper wire to pin 1 of jumper position J2. IC39 pin 12 was then connected with another jumper wire to IC12 pin 18 (CPU, Address Bus 14). The effect of this is to place the upper half of the 2K ROM at position 3 above the data from the ROM at position 5 in the address space. Without these modifications, the upper half of ROM3 is not addressable.

Note that the 1B1110/1 is probably the most useful and versatile of these four revisions, since it has the RAM reset feature, and support for Switch Matrix Row 7. It would work for any game except for Locomotion, but could be modified in to a 1B1110/1a if needed. The 1B1110/0 is almost as versatile, since it has the RAM reset feature, and support for Row 7 is only important for the 1B1149 settings board, which could be ignored in a home environment. If needed, the 1B1110/0 could be modified by adding a jumper from IC26 pin 7 to CN9 pin 9, effectively turning it in to a 1B1110/1. The 1B1110/1a will only work in a Locomotion, but could be easily modified back to a 1B1110/1 with a few simple changes.

ROMs and Jumpers

ROM Jumpers
ROM1 Jumpers
JumperSignalConnects To
J3AB10Pin 19
J4VDD (+12V) Pin 19
J7GND Pin 21
J8VCC (+5V) Pin 21
J9VGG (-5V) Pin 21
J10GND Pin 18
J11VCC (+5V) Pin 18
J1Chip Select Control  
ROM2 Jumpers
J17Chip Select Control  
J18Chip Select Control  
ROM3 Jumpers
JumperSignalConnects To
J5AB10Pin 19
J6VDD (+12V) Pin 19
J12GND Pin 21
J13VCC (+5V) Pin 21
J14VGG (-5V) Pin 21
J15GND Pin 18
J16VCC (+5V) Pin 18
J2Chip Select Control  

These jumpers control voltage, ground, and addressing pins on the ROMs. As far as I can tell, J7 and J11 should always be out, and J10 (2/3) should always be in. Similarly, J12 and J16 should always be out, and J15 (2/3) should always be in. I do not know what types of chips J7/J11/J10, J12/J16/J15 are intended to support.

2716 or TMS25162K EPROMJ8 (1/2) inJ9 out
J3 (1/2) inJ4 out
J1 in
J17 (1/2) outJ18 in
CN1350N2K ROMJ8 outJ9 (2/3) in
J3 (1/2) inJ4 out
J1 in
J17 (1/2) outJ18 in
27081K EPROMJ8 outJ9 (2/3) in
J3 out J4 (2/3) in
J1 out
J17 (1/2) inJ18 out

2716 or TMS25162K EPROMJ13 (1/2) inJ14 out
J5 (1/2) inJ6 out
J2 in
CN1350N2K ROMJ13 outJ14 (2/3) in
J5 (1/2) inJ6 out
J2 in
27081K EPROMJ13 outJ14 (2/3) in
J5 out J6 (2/3) in
J2 out


ROM Types: The Texas Instruments TMS2516 is equivilent to everybody else's 2716 designs. It requires only VCC (+5V) to operate. The Texas Instruments TMS2716 is not compatible with anybody else's 2716 because it is a three-rail power supply device, similar to the 2708, requiring +5V, -5V, and +12V to operate, but uses pin 20 for the +12V supply. None of the jumpers on these boards configure them to put +12V on pin 20. This is probably not a big deal, as the TMS2716 is an oddball that nobody is likely to have, need, or want support for.

The CN13503N seems to be similar to the 2716 design, but with the additional -5V supply requirement typical of the 2708. Not much is available on this chip, but from the jumpers settings needed to support it (thanks, Frank, for figuring this part out), it appears to be a cross between the 2708 and the 2716, using +5V and -5V supply voltages, but with pin 20 as the Chip Select line.

There are some notes on Leon's site ( http://www.flipper-pinball-fan.be) on converting these boards to use 2716 EPROMs to replace the difficult-to-program 2708s. I don't use these adaptations, because I have an EPROM burner that supports the 2708 chips and a healthy supply of spares. As of this writing, Chris at http://www.pinballroms.com can supply 2708 EPROMs burned with the Zaccaria game image of your choice.

Schematics Errors

There is an error in the schematics for the 1B1110 CPU boards used in the earliest games (Winter Sports, Future World). The +12V (VDD) and -5V (VGG) voltages are shown on the wrong pins of the five ROMs. +12V (VDD) should be connected to pin 19, and -5V (VGG) should be connected to pin 21. By the time of the 1B1110/0 board revision (Hot Wheels), this error was corrected.

General Illumination Lighting and Processor Reset

These two items would not ordinarily be found together, but it turns out that the GI lamp circuit is critical to the operation of these games. Without it, the game cannot boot. The reason is that the bridge rectifier P3 on the power supply board takes its AC input from the GI lamp circuit, and is labled as being a +5.3VDC (VRM) power supply output. Tracing this through the schematics, the only place it is used is to feed the RESET circuit on the CPU board. So, without a working GI lamp circuit, the CPU cannot start and the game will not boot. This makes the scorched connector problem on the 1B1109 board even more problematic, since it would affect the GI circuit input on the board, leading to a non-working game when the connector fails.

Signetics 2650A

I have not seen many Signetics 2650 failures, even on badly corroded boards (the socket tends to protect the chip by being destroyed first), but have run in to CPU boards that were missing this chip. Replacements for this chip are scarce, but available. Note that Signetics made two processors, the 2650 and the 2650A. The 2650 runs at a slower clock speed than the 2650A. Zaccaria games require the faster 2650A processor chip. These were also used in some early home gaming consoles like the Emerson Arcadia 2001.

David Gersic

Copyright © 2001. All rights reserved.

This document may be freely distributed so long as the content is not modified.

Last updated 29 September 2019