A: We set out to make The Ultimate MPU Board fit several needs. Our first goal was to produce a MPU board that could handle all of the different versions of MPU series boards that both Bally and Stern manufactured between 1975 and 1984. Another important goal was for all of the games, including free play versions to be installed on one board eliminating EPROM changing. We wanted the new MPU board to have a dipswitch for easy switching between the different games and to eliminate any complicated jumpering system.

An additional goal was to make a board that would satisfy the replacement needs of both operators and home owners/collectors. The consideration for the operator is that they need a MPU board that is rugged enough to run 24/7. The need for the home owner/collector is a board that can be easily installed and set up for their particular game.

Last but not least, one of our goals was pricing. Make a board that can sell for under $200. Also we wanted to be able to offer distributors/operators attractive quantity discounts making the need to repair old damaged MPU boards a thing of the past.

A: We chose to go with a 6116 for several reasons. One reason is the 6116 is widely used and will be readily available for many years to come. Using an AA battery backup system shouldn't be compared to the old Ni-cad battery source on original MPU boards. There were several reasons that the old Ni-cad batteries damaged the boards, the main reason being the batteries were left for years on the boards. The batteries (being soldered in) made it difficult to remove them, and many people ignored them until it was to late. Since we are using a low power version of the 6116, the battery drain is very small meaning that you will get about 2 - 3 years life on a set of fresh alkaline batteries. Newer battery designs also make the leaking of the batteries much more unlikely unless you choose not to change them for several years after they are spent. Finally, cost was a big consideration. Using the 6116 with the battery holder can be done for a quarter of the cost as compared to using the Dallas or FRAM chip.

For people who do not want to mess with AA batteries, for a nominal charge of $10, ordered from this web site, we are offering the Dallas Semiconductor DS1220 chip that is a drop in replacement for the 6116 and AA batteries. The chip has a lithium battery built in that is rated for a minimum of 10 years. We have designed several projects using Dallas Semiconductor memory that are over 14 years old and still don't need replacement. They won't leak and they are a proven solution. The Dallas part also has an unlimited amount of read and write cycles, which is very important. At any time a board can be changed back to using a 6116 with AA batteries and vice versa.

Q: What about the new FRAM such as the Ramtron FM1808? They don't require any batteries. Why don't you use one of them?

A: The biggest reason not to us this technology is that it is not suited for this application. These devices have a limited number of read/write cycles. Because the Bally/Stern program is reading/writing into the ram chip all the time, the life cycle of the device is greatly reduced. The applications engineers at Ramtron agreed that using a FRAM in such an application wouldn't be advisable because the constant reading and writing to the chip significantly degrades its usable life. Thus, the use of a FRAM did not meet our design criteria of producing a board that was better than the original.

A: We have designed the board to be a universal replacement board to be used in either a commercial or home environment. That's why we can offer a flat one-year warranty no matter if The Ultimate MPU Board is used in the home or business.

A: The size of the original board was based upon mid 70's manufacturing techniques and then available components. We chose to make the board as small as possible without requiring any modifications for mounting. The mounting rails have 6 holes, four holes in the corners and 2 in the middle. What we chose to do was use the lower four holes. The existing cables reach without any strain. This physical reduction in size reduced the cost of the printed circuit board in half, enabling us to pass the savings on to the customer. Our board also has less components which use less space and less power.

A: By using a PLD, we were able to make the switching of different games as easy as using a dipswitch. This will allow anyone that is not comfortable with electronics to be able to change to any one of 85 different games. The PLD contains complex logic that eliminates the need for jumpers and reduces the over all component count.

A: This jumper will allow you to switch from a 500Hz clock rate to a 1Mhz clock rate that is used by the Stern's MPU 200 series. Many Bally pinball machines will not operate correctly at 1Mhz clock speeds.

A: This jumper will allow the board to be used with the Bally -133 series games or any original MPU board that used a diode at CR52 instead of a resistor at R113. Later Bally/Midway machines used the General Illumination (6.3VAC) for the zero crossing. The zero crossing is a circuit that detects when the AC line is at 0V. This is required to synchronize the microprocessor on the board, to control the lamps and solenoids.

Q: How did you manage to make The Ultimate MPU Board compatible with Stern MPU 200 series

A: By allowing the board to have a jumper for the clock speeds and using our Programmable Logic Device is such a way to make up for the (2) 5101 chips that were used on the original Stern MPU 200 series boards.

A: We feel very strongly about making this an open product. That is why we have posted on this web site the schematics, board layout, and pictures of The Ultimate MPU Board. We will continue to update our documentation and support. We will also be offering replacement parts or you can chose to use our flat rate repair fee plus parts after your warranty expires.

A: Resistor and capacitor networks are more cost effective. They reduce the overall component count, and reduce the overall size of the board. This allows us to manufacture a board for less. The networks also provide a filter that protects the sensitive components from static and the inherent electrical noise found in a pinball machine.

A: This is accomplished using the game option dip switches. Setting the game select switch to the free play mode for whatever game you have enables the free play mode. For simplicity, the free play mode is the same as the regular mode except SW8 (leftmost) on the dipswitch is on. Once the free play mode is enabled, turning off the credit display dipswitch activates it.

Q: How do you switch to on-board diagnostics?

A: On-board diagnostics are enabled when the left most two game select dip switch switches are on. We will be adding more info at the Advanced technical info section.