Sentinel / Wonder Wizard
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1 Introduction
Sentinel, Inc. which was a division of Magnavox Consumer Electronics Company (North American Philips, or simply NAP) manufactured four models of home version pinball machines in 1977 and 1978. They used the Wonder Wizard trademark on the machines. The trademark was registered by General Home Products Corp., a division of Magnavox Consumer Electronics Company. The trademark (registration number 1066305) was active from August 5, 1976 to October 18, 1983 and is now cancelled.
2 Games
- Flying Aces (1977) Model number PH7730WA01 with a flying theme.
- Demolition Derby (1977) Model number PH7730WA02 with a car crashing theme.
- C.B. Charlie (1978) Model number PH7730WA03 with a trucker/ CB radio theme.
- Star Explorer (1978) Model number PH7730WA05 with an outer space theme.
- Star Explorer (1978) Model number PH7730WA15 same as above, but made by Philips Electronics for Canadian distribution.
CB Charlie and Demolition Derby home model pinball machines.
Flying Aces and Star Explorer home model pinball machines.
All of the machines had the same cabinets and playfield layout, but with different artwork.
3 Technical Info
Sentinel, Inc. machines were covered by the now expired patents 4203602 (the ball is used as an electrical switch between two "hot" contacts) and 4109916 (one coil mechanically operating two devices). This was unique in that it lowered manufacturing costs by not having to use as many coil assemblies or the circuitry to drive those assemblies.
Backbox dimensions: 17" high by 22" wide by 9" deep.
Main cabinet dimensions: 46" long by 20.5" wide by 6.5" deep.
Assembled machine weight is 68 pounds.
Motherboard: # 702605-1
Display board: # 702604-1
Solenoid driver board: # 702603-1
Audio board: # 702602-1
Owner's Manual which applies to all four Sentinel machines (does not contain any schematics).
Sentinel and Wonder Wizard Owners Manual
4 Problems and Solutions
4.1 Power Problems
There are two power supply bridge rectifiers on the motherboard in the backbox. BR401 and BR402 are both type RC204-1 (2 amps @ 400 volts). It is strongly suggested to upgrade these to 8 amps @ 400 volts. Radio Shack bridge rectifier # 276-1181 will be fine to use.
Motherboard showing the two bridge rectifiers as well as the master volume control.
Circuit breakers and power switch are on back of machine.
4.2 Solenoid Problems
On solenoid driver board # 702603-1 there are five driver transistors and 5 smaller pre-driver transistors. Q301, Q303, Q305, Q307, and Q309 are the solenoid driver transistors and are "house marked" as RCA 393. These are actually type 2N6099, and can be substituted with the common TIP 102 transistor, which is used in most other commercial pinball machines. Q302, Q304, Q306, Q308, and Q310 are the pre-drivers and are "house marked" as 1482. These are actually type 2N4401 or NTE 123AP transistors.
The solenoid driver board showing the 2N6099 driver transistors (the large ones) and the 2N4401 pre-driver transistors (the small black ones).
4.3 Lamp Problems
4.4 Switch Problems
4.5 Display Problems
The digital display on 702604 display board develops bad solder joints on the pins of the display itself. Be sure to check the soldering of those pins if display problems are being experienced.
Look closely at the pins of the display for bad solder joints on the foil side of the board.
4.6 Sound Problems
The volume control pot is soldered to the 702605 motherboard in the backbox. The shaft of the control gets banged around alot which causes the terminals of the control to develop bad solder joints on the motherboard.
There are several pots on the audio board. Don't play with them. Be sure to clean the foil fingers of the edge connector.
4.7 Flipper Problems
These are old classic Stern Generation 1 flipper assemblies operating on 24 to 28 volts DC. Some parts are reproduced by Pinball Life. The 3" flipper bats have an offset pivot point. If using standard 3" bats, the tips of the flippers will be too close, and the ball will not be able to drain. These machines should have had 2" Gottlieb flat top flipper bats # A11242-3A Blue plus # A6888E Thin Shoe & Shaft plus Screw # HDW-632-1-1/4.
Notice the 20 ohm 20 watt resistor connected to the terminal strip. It is connected in series to the flipper coil to reduce power for holding. The end-of-stroke switch shorts (bypasses) the resistor during the pull-in time. Then the switch opens thus putting the resistor in the circuit to drop power for the holding function. The resistor can get very hot which is why they put a piece of sheet metal behind it to prevent burning the wood. It would be a better idea to replace this coil/resistor setup with a normal 24 volt flipper coil such as a Gottlieb # A-20095. Then the resistor and piece of sheet metal could be eliminated completely.
4.8 Pop Bumper Problems
These are classic Stern/Chicago Coin pop bumper assemblies with the coil operating on 24 to 28 volts DC. There is no skirt or bumper return spring since the electrical circuit is made by the ball contacting the metal ring on the playfield and the rod & ring. You can use a Williams # 04-10888 or B-7417 coil bracket to replace the original bracket.
4.9 Slingshot Problems
These are old Stern/Chicago Coin slingshot assemblies with the coil operating on 24 to 28 volts DC. The electrical circuit is made by the ball contacting the metal strip on the playfield in front of the slingshot and the metal spring around the plastic posts. There is no rubber ring around the slingshot because of this. You can use a Williams # 04-10888 or B-7417 coil bracket to replace the original coil bracket.
4.10 Eject Hole Problems
If the coil or its diode are shorted or the driver transistor is shorted, the circuit breaker will trip.
The microswitch signals the board to score points then fire the eject coil to kick out the ball.
4.11 Outhole Ball Return Problems
Sentinel made their own outhole ball return assembly. It would appear that an old Stern plunger & link assembly may work as a replacement if the original one is worn or damaged.
Sentinel made their own ball trough assembly out of one piece of sheet metal.