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 six 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 Raid (????) Model number PH7730WA06 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.
Star Raid home model pinball machine.
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
Coil numbers and applications:
- 361669001 (also known as 1669-1) has a 1N4004 diode connected across it. This coil is used in this machine for the pop bumpers, slingshot kickers, eject hole kicker, and flipper coil. A suggested modern replacement if an original cannot be located is a Williams # AE-23-800-01. If the replacement coil does not have a diode, be sure to install a 1N4004 diode with the banded (cathode) side connected to the same terminals and wire colors as the original being replaced.
- 361669002 (also known as 1669-2) has a 1N4004 diode connected across it. This coil is used in this machine only as the outhole ball return kicker. A suggested modern replacement if an original cannot be located is a Williams # AE-27-1200. if the replacement coil does not have a diode, be sure to install a 1N4004 diode with the banded (cathode) side connected to the same terminals and wire colors as the original being replaced.
Raising the playfield and looking inside the cabinet. Be careful when raising the playfield, the wires to the flipper buttons are short. There is no prop stick in the machine so you will need to make your own out of an old broom handle or pool cue stick cut to size.
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. If the circuit breakers keep tripping, be sure to check first for burnt playfield coils, shorted solenoid driver transistors on the driver board, and shorted bridge rectifiers on the mother board.
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. It appears that the manufacturer had thought about having an additional coil on the playfield. They have empty places on the solenoid driver board for driver transistor Q311 and pre-driver transistor Q312.
The solenoid driver board showing the 2N6099 driver transistors (the large ones) and the 2N4401 pre-driver transistors (the small black ones). All solenoids operate on 24 to 28 volts DC.
4.3 Lamp Problems
There are three "ball in play" LED's on the display board. The manufacturer left two empty spots on the board which would appear they thought about having a selectable 3 or 5 ball game.
4.4 Switch Problems
Sentinel did not use the normal rollover switches or standup switches. They used what looked like bent paper clips that touch each other as standup switches behind the rubber rings. Instead of a slot cut into the playfield for a rollover switch assembly, Sentinel used a series of three metal strips attached to the top of the playfield to act as rollovers. The metal ball completes the circuit by touching either the top to middle strips or the bottom to middle strips.
The metal strips are glued to the playfield. They must be kept clean and shiny in order to work correctly.
The tilt assembly is a phony "ball-and-chain" setup and is not very good. It is suggested to replace this assembly with the conventional plumb bob parts available from the usual pinball parts suppliers. Doing so will make the tilt more reliable.
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 2 flipper assemblies operating on 24 to 28 volts DC. The corner of the frame was modified by Sentinel by chopping off one corner in order to clear the outhole trough and the terminal strip. Some of the flipper parts are reproduced by Pinball Life. There is only one flipper assembly and it has a linkage connected to it to operate the other flipper bat. When the flipper coil pulls in, both flipper bats will move at the same time. Both flipper button cabinet switches are wired in parallel so that pushing either button will operate the flipper assembly. 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 (coil number 361669001 also known as 1669-1) 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. With the metal ball completing the circuit, this sends a signal back to the game board to score points and fire the pop bumper coil. An improvement/upgrade would be to remove the metal ring from around the pop bumper and install pop bumper skirt of desired color, pop bumper base spring, and a conventional pop bumper spoon switch assembly. This would make the pop bumper back into a normal one.
If there ever is a problem with the coil bracket, you can use a Williams # 04-10888 or B-7417 coil bracket to replace the original bracket.
The metal rings are glued to the playfield. The glue often fails after this many years and the ring starts lifting. The metal must be kept clean and shiny to make good electrical contact or weak pop bumper action will result.
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.
The metal spring (used instead of a rubber ring) around the posts and the metal plate on the playfield are two electrical contacts. The metal ball touching both at the same time complete the circuit and signal the gameboard to score points and fire the coil. The metal surface must be very clean and shiny to make good contact. Notice the glue has gone bad on the metal strip and it's lifting away from the playfield.
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.