Midway Rotation VIII

Note: This page is a work in progress. Please help get it to a completed state by adding any useful information to it.

This section is dedicated to the repair, preservation, restoration and maintenance of Midway's Rotation VIII and The Valley Company's Spectra IV.

= Midway's Rotation VIII

1 Introduction

This section is dedicated to the repair, preservation, restoration and maintenance of Midway's ROTATION VIII. Intended to be a repository of information as well as a resource to owners, I hope this will be of value to those interested in making one of history’s most unique pinball games operational and fun to play.

The information contained on this site has been collected in many ways. Much of it has been collected by word of mouth or gleaned from forums or other sources. Some information was gained from first hand experience in repairing a number of these machines.

2 General Information

2.1 Rotation VIII Value:

Value and sale price of a Rotation VIII has come up on a number of forums. I know of a few working Rotation VIIIs that have been sold. The first was late fall of 2012 on E-bay at just under $2000 US near Chicago. A second was during the summer of 2013 in the Seattle area at $2500. Several others in the same area sold during 2014 in the range of $1500 $1700. All but one of these machines used my replacement daughter board. Most of the non-working but complete machines I know of seem to sell between $500 to $800. European prices for non-working machines seem to be considerably more. Condition and completeness are always deciding factors.

2.2 Original US Patent for Rotation VIII

Click here.

2.3 History

Designed in the infancy of solid state pinball machines, Rotation VIII is unique in that it Game is a cocktail table game with an automatic rotating playfield. Up to four players can sit around the table with the playfield turning sequentially to their position to play.

Known serial numbers range from 0216 to 0432 in North America and serial numbers from 0635 to 0737 appearing in Europe. 0696 appears in South America. It now seems likely that the lower number serials from 0200 to 0499 may be North American and the range from 0600 to 0799 represent machines exported out of North America. The difference noted so far between the North American machines and the ROW (Rest of World) machines seems to be in the power transformers with ROW machines having windings supporting 220 volts.

To date, there is no definitive number of how many ROTATION VIII's were produced. Guesses have placed the production run in the range of several hundred to 1000. The serial numbers found so far suggests that the number may be in approximately 400. Rumours also stated that some of the games may have been taken back by the manufacturer due to reliability problems. Production commenced in 1978, but we don’t know how long production continued. Many of the surviving games are now sitting in garages, basements and warehouses because they don't work. Only a handful are now operational.

2.3.1 Where is my Serial Number? Serial

The serial number is usually printed on a small light cardboard tag stapled to the inside of one of the coin doors. On some machines, the serial number may also be stamped into the horizontal shelf near the coin door. I have never found any serial number information on the playfield or anywhere else on the cabinet or frame.

3 Technical Information

3.1 Hardware Addressing

Port reads:

$21: matrix switches $22: keypad inputs

Port writes:

$00 .. $02: display data $03: lamp data $04 .. $07: solenoids $10 .. $17: sounds $23: switch / lamp / display column

Memory:

$0000 .. $17ff: ROM $1800 .. code extension $c000 .. $c1ff: RAM $e000 .. $e01f: NVRAM

Display data:

$00: Digit data A and B (bcd-coded, high and low nybbles) $01: Digit data C and D -"- $02: Digit data E and F -"-

$23: remember the strobe column value (0 .. 6) used, then: data A is written to position (strobe) of the 1up panel, data B is written to position (strobe) of the 2up panel, data C is written to position (strobe) of the 3up panel, data D is written to position (strobe) of the 4up panel, data F is written to position (strobe) of the lower panel.

You might wonder about data E? In fact it's not output, and contains some data the game needs for calculations (like the match digits).

Thanks to Gerrit Volkenborn for the addressing information.

4 Problems and Solutions

4.1 Summary of Issues

One of the primary causes of non-operating Rotation VIIIs is the original Characterization Board (daughter board). This board was subject to considerable corrosion from the memory battery. Further problems resulted from dirty or worn connector contacts also on the characterization board. As well, the characterization board used tri-power eproms which were touchy and had sockets that were prone to failure. In severe cases, the logic board has also been corroded from the Characterization board. Replacement of the Characterization board, updating the reset circuit and re-pinning connectors, especially the power supply lines on the logic board may bring a machine back to life. Unfortunately, many logic boards also have failed components and corroded traces.

As is the case with 40+ year old technology, many if not most of the active components on these boards are obsolete and may at times be difficult to find exact replacements. To date, some "drop in" substitutions have been found for several difficult to find components. This information is contained in the Technical page.

The rotating circuitry and equipment is robust but needs to be calibrated to work properly. The playfield will not rotate if a ball is not in the outhole. There are also several mechanical issues related to moving parts that will cause instability. Playfield parts are mostly stock and can be purchased from suppliers.

4.2 Getting your board to boot

The following summary is intended to be a troubleshooting guide for the electronics in Midway’s Rotation VIII.

As you have probably already noticed, the circuit boards used in this machine are not used in any other machine. As well, there are virtually no self-diagnostics available to help resolve machine electronic faults.

This guide assumes you have a reasonable understanding of electronic repair, have good soldering skills, can remove and replace components including DIP components, have basic electronic testing equipment and can read a schematic. An oscilloscope would be helpful, but a reasonable logic probe may still work.

4.2.1 Main Board

A little background on the main control board first. The main board is based on a Z-80 processor. The Z-80 processor uses separate pins for the address buss (16 lines) and the data buss (8 lines). This address and data buss all pass through to the daughter board which holds the 2716 style eproms and the NV memory. The daughter board also generates the RD (data read) signal used by a number of components on the main board.

Now, to add another level of complexity, the designer, I’m sure in his or her infinite wisdom, chose to use several additional components originally designed for the 8080 and Z-85 processors, and here is where the rub comes in. These two possessors used multiplexed data and address lines, in other works, the lower 8 address bits share the same lines as the 8 data bits. That means in addition to the 16 address lines and 8 data lines on the Z-80, you have another 8 other lines that can have data or address.

So, unless everything on the two separate address and data busses including the daughter board work, the main board will not boot. The main board is smart enough to send itself a reset pulse if it does not boot within a certain amount of time. Monitoring that reset line will give the trouble shooter an indication that the board is trying to boot, but is not successful.

OK, have I scared you yet?

Having repaired a number of main boards, there are a couple of common faults that may be encountered. Before starting any diagnosis, I am assuming that all voltages have been checked, connectors are solid and all boards are in place. I’m also assuming the main board does not show corrosion damage.

Situation 1) Turn on machine and nothing happens, only GI lights come on, no table movement and no controlled lamps are lit.

• First check pin 2 of J8. A solid high indicates the reset is not active and is normal. A machine booting normally will have a steady voltage of around 4.8 volts on this pin.481x446px This condition is highly unlikely in a non-booting board and, if present, is probably caused by a faulty reset circuit or loss of the clock signal. A solid low signal is also a reset fault and will not allow the processor to operate. Pin 10 of A1 should have clock. If it doesn’t, start trouble shooting the clock circuit including B1. If the clock signal is present at A1, check the reset circuit in chips A1, A2 and A3 for faults.
• If you have a continuous series of pulses on J8, pin2, you could have a fault in the daughter board, and/or either of the buss drivers F3 and H3.
• Examine the daughter board carefully for any signs of corrosion. I have had nothing but grief with this board. Even the slightest bit of corrosion seems to cause the daughter board to fail. If you have access to a known good daughter board, or have access to my replacement daughter board, try it to see if the main board will boot.
• Replace the buss drivers at F3 and H3 (8304 and 81LS95). Failure of these chips seems quite common and probably results from a failure on the daughter board. Even with an oscilloscope, I have never had much luck in determining which of the two chips is bad, so as a matter of practice, I replace both.  
• With a good chip in F3 and H3, hopefully you will now be in situation 2 below or better yet the main board boots.

Situation 2) Power on and random switched lights, solenoids and/or table movements and no start-up tune.

• In most cases, this will happen with a bad daughter board and/or faulty solder joins of the connectors to the daughter board. Have I mentioned how much I hate the original daughter board?
• Reflow solder on daughter board and main board connectors.
• Check presence of all three voltages on the daughter board.
• Slightly wiggle and twist the daughter board as the machine is turned on, anything different?
• Reseat the three TMS2716 chips.
• Still nothing? You may be in a situation needing further diagnosis. Time for us to talk.

Situation 3) Power on, board boots and plays a tune, but as it boots, you get random solenoid firing.

• Upgrade the reset circuit as I outlined here.

4.2.2 Motor Driver Board

This board will commonly fail, usually when anything gets in the way of the rotating table. Wires, cables, almost anything can cause it and the fuse rarely protects it.
The good news is that this board is easily repaired. Usually what happens when one of the driver transistors fail is the table will turn in one direction only, cannot correct for an overshoot and will not start a game. Almost always, the failure will be one of the Darlington pair transistors, TIP 110 or TIP 115. All four are easy to replace and are commonly available.

Occasionally, if the Darlington transistor drivers are good and the table does not move, the problem may be in the large 3.3 ohm resistor. Check it for continuity. Rarely the LM3900 goes bad, but it can happen.

5 Repair Support

5.1 New Service Provider

John Robertson of John's Jukes has taken on the existing stock of parts and board servicing. John can be reached at https://www.flippers.com/.

5.2 New Integrated Logic Board

Note: no longer available.The new logic board is complete! It has integrated the daughter Logicboard onto the mainboard and have updated the power on reset and clock circuit. It is basically a re-do of the original board with a few modifications. The prototype board has been stable and reliable. The photo to the left is the first production board. All boards will only have sockets for the memory, Z-80, 8156 and audio generator.

5.3 New Display Boards

Like most items on a Rotation VIII, the display board is absolutely unobtainable. On one Display machine I was working on, all but one of the displays had burned segments and warped red lenses. I found a conventional 7 segment display that worked on the signals available and had a replacement PC board etched. The result is not an exact appearing replacement, but is functionally identical and actually has a slightly larger display. These require a slight bit of filing on the apron opening, but otherwise are a plug and play replacement. Check out New Boards for detailed information.

5.4 Next Project

I've had a few inquiries for Motor Drivers. I have done the design, but have not ordered any bare boards yet. E-mail me if your interested.

6 References

The Gallery has a new series of detailed photos. They were taken of Chris Welsh's machines. One machine was like new. These were the machines used in the recent Northwest Pinball and Arcade Show.

A supply of replacement daughter (Characterization) boards are on hand.

7 Northwest Arcade and Pinball Show - Tacoma

Two machines belonging to Chris Welsh

8 Videos

Below are three YouTube videos showing a fully operational machine in three different modes.

 

 

8.4 Simple two player game

 

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