Valley Spectra IV

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This section is dedicated to the repair, preservation, restoration and maintenance of Valley's Spectra IV.

1 Introduction

This section is dedicated to the repair, preservation, restoration and maintenance of Valley's Spectra IV. These are very special and unique machines. It was the only pinball machine manufactured by the Valley company (known for Billiards equipment) and one of only two solid state pinball machines where the entire playfield could rotate for additional players instead of trading positions in front of the machine. Players still have the option of leaving the playfield in place and the players can move as traditional pinball games.

2 General Information

2.1 Unique features

Besides the rotating playfield there are some other unique things going on with this machine. One was the way the difficulty level is adjusted on the machine. On traditional pinball games it is common to adjust logical settings via DIP switches. Often they have a moveable post by the outlanes or slings to adjust the size of the opening. Instead, Valley took a different approach by having two voltage settings for coil power. This is set by a toggle switch on the underside of the machine. Lower voltage made it harder to make some shots while on the high voltage setting it is much easier to reach the top. Oddly that operator setting is exposed on the bottom where players could just make it easier if desired. It's a mystery why that toggle wasn't hidden inside the coin door.

Another unique feature is related to the two kick-out holes. Each one has a set of 4 screws to adjust how the ball sets in the hole. By adjusting the height if them the angle that the ball is kicked out can be adjusted.

2.2 Getting access to circuit boards

Accessing the circuit boards to remove them for servicing is not obvious or intuitive! They are all mounted in a card cage that is directly attached to the underside of the playfield. If they need to be removed first all the cables need to be unplugged from the boards. There are edge connectors (similar to what Gottlieb used) that go to each of the three boards in the cage. Some boards have these on both sides. The lamp board which is the one exposed also has 6 standard .156" molex plugs that pull off. After that there is one screw (the original was supposed to be RED) that needs to be removed. It is screwed into the side of the cage that holds one end of the plastic rails that the boards slide into. Once that screw is removed the rails pivot on the other end allowing the cards to tilt out and then then can slide out of the cage. There is a picture in the manual for the game that also explains the process.

The tilt board is directly accessible when the playfield is propped up.

4 Problems and Solutions

4.1 Summary of Issues

The main cause of non-operating Spectra IV machines is the same the number one killer of all pinball machines. Leaking rechargeable batteries. The MPU board has a set of three 1.2V AA NiCad batteries soldered to the MPU board. In most machines these ended up leaking and caused considerable corrosion on the MPU board that would etch away traces causing open circuits and even up into the sockets on the board. Because the MPU is the top board in the stack they could leak down on the Solenoid/Sound driver board right below it causing damage to that board as well. To get one of these machines going all the corrosion has to be properly dealt with.

As is the case with 40+ year old technology, many of the active components on these boards are obsolete and may at times be difficult to find exact replacements. They do share many of the common electronic components but there are a few unique parts that are not so common. To date, some "drop in" substitutions have been found for several difficult to find components. This information is contained in the Technical page.