Fischer

{{WIP}

1 Introduction

Fischer, the large pool table manufacturer, decided to get into the home model pinball market in 1977.

Fischer, A division of Questor Corporation, P.O. Box 50, California, Missouri 65018.

2 Games

• Skyhawk, model number 3019. Made in November 1977.

Skyhawk home pinball machine

3 Technical Info

There are two circuit boards in this machine. Board 710A is located in the backbox and handles game logic, score display, and sounds. The manual calls this board the "Upper Printed Circuit Board". Board 710B is located on the underside of the playfield and handles the switches and solenoids as well as provides the 7 volt and 28 volt dc power supply. The manual calls this board the "Lower Printed Circuit Board".

Fischer home pinball machines were covered by the now expired patent number 4109916 in which one coil mechanically drives two devices. In this machine that patent would have pertained to the slingshot kicker.

There are two manuals printed. One is an "Assembly" (owner's/operating) manual which was supplied with the machine. Sold seperately was a "Service" manual (# 11-77-600) which included a schematic of the playfield and had some parts lists. There were no board or power supply schematics with this manual. Fischer distributors were the only entities which were supposed to perform board repairs. Therefore, only the distributors received the circuit board schematics at the time.

File:Skyhawk-Service&Parts.pdf

4 Problems and Solutions

4.1 Power Problems

On the power transformer are two circuit breakers. The red wires going to a 2.25 amp breaker are for the input to the bridge rectifier for the 28 volt coil circuit. The blue wires going to the other 2.25 amp circuit breaker are for both the general illumination and the game logic power supply.

On the 710A board in the backbox, diodes D1 through D6 are the power supply diodes for this board. There are two filter capacitors in this section also, a 2200 uf @ 16 volt and a 1000 uf @ 16 volt.

4.2 Solenoid Problems

All coils operate on 28 volts DC. The solenoid driver transistors are located on the "Lower PC Board" attached to the underside of the playfield. Transistors Q8 (type SE9300 or TIP102) is the driver for the slingshot kickers. Transistor Q6 is it's pre-driver (type TIS98). Both of these are driven from IC 5 and IC 2. Transistor Q7 (type SE9300 or TIP102) is the driver for the eject hole. Transistor Q5 is it's pre-driver (type TIS98). Both are driven from IC 1. The TIS98 transistor can be replaced with a 2N4401 and observe lead pinout.

4.3 Lamp Problems

If just the general illumination is out and the bulbs are good, then check diodes D5 and D6 on the 710B board located on the underside of the playfield.

4.5 Display Problems

IC 1, IC 2, IC 3, IC 4, and IC 5 on the 710A board in the backbox drive the score display assembly.

4.6 Sound Problems

This machine uses a 40 ohm speaker. Yes, that's right, 40 ohms! Intergrated circuit IC 7 on the 710A board in the backbox is the amplifier chip.

4.7 Flipper Problems

This machine uses classic Stern Generation 1 flipper assemblies but with a single section coil. What Fischer had designed was the end-of-stroke switch would cut-in a 20 ohm 5 watt flex resistor in series with the coil to help prevent the coil from burning up. Well, it does not really help much. Even the resistor gets VERY HOT. Fischer installed a piece of ASBESTOS under the resistor to keep from burning the playfield! A suggestion for improvement is to remove the original coil, resistor, asbestos pad, and replace with a real flipper coil. I would suggest using a Gottlieb A-20095 flipper coil which could then be wired to the end-of-stroke switch normally. Observe diode polarity on the replacement coil.

4.8 Pop Bumper Problems

The pop bumper coils are directly driven by the high current contacts of the spoon switch exactly like on a Gottlieb System 1 machine. The other switch on the pop bumper is the scoring switch. So if the spoon switch gets stuck, the coil will burn up! A Gottlieb A-5194 coil will work as a replacement. Just observe the diode polarity.

4.9 Slingshot Problems

The slingshot coil operates on 28 volts DC and can be replaced with a Gottlieb A-5194 coil. Just be sure to ensure correct polarity of the diode.

4.10 Eject Hole Problems

The eject hole coil (28 volts DC) can be replaced with a Gottlieb A-5194 and be sure to observe which machine wire goes to the banded side of the diode.