There are several similarities between these systems and Williams System 11, although Data East and Sega would deny that. But those who are familiar with Williams System 11 may feel right at home here.
This section covers checking to insure the voltages are present. It also covers troubleshooting non-working solenoids.
Understanding the Layout
All version have the following circuit boards:
* CPU Board
* Sound Board
* Power Supply Board
* PPB Board (the first two, Laser War and Secret Service, have only a 50 V flipper supply)
* Flipper Control Board (located in the cabinet)
There are also separate bridge rectifiers and capacitors located off the boards in the backbox.
Some may have a shaker motor board in the cabinet.
Testing the Power Supply
What can go wrong
1) Fuse blown. Common. Can be a bad fuse. Or another issue like a blown rectifier.
2) Bridge rectifiers fail. Common. Will be checked with voltage testing.
3) Voltage regulator fails. If voltage is good, then the regulator is good. The 5V regulator on this board does not fail too often.
4) Connectors burned or fail. Common. Visually look for burned connectors.
5) Board failure. Burned traces. Bad connector pins. Common. Will check visually.
6) Main +18 V capacitor gets old and fails. C1. C2, C3 or C7 fail.
7) Main fuse is blown. Unplug the power, remove and check the fuse in the can in the cabinet.
8) Transformer fails. Extremely unlikely. Will be checked under voltages.
The DE/Sega system 3 has two different power supply boards: “PS Power Supply” and “PPB Board”, plus two rectifiers and a capacitor located by themselves in the backbox. Each needs to checked separately. Additionally, the sound board has two voltage regulators. And the Solid State Flipper Board has a low voltage power supply which provides the ‘hold’ power for the flippers.
Off the Boards Backbox Voltages
Note: As far as we know, all DE and Sega System 3 & 3B pins have two fuses, one before each of these bridge rectifiers. They should be located nearby. If your’s does not have them, install a fuse and holder on the AC side of each rectifier and let us know.
There are two rectifiers located by themselves in the backbox. These supply the +18 V DC to the power supply board and the solenoid voltage to the coils (not the flippers).
The first drawing shows the main power transformer and the AC outputs. The 6 V AC powers the GI lamps. The rest of the outputs go to the various power supplies and are converted to DC.
The first of these power supplies is in the second picture – the two bridge rectifiers. BR1 along with C1 converts the 13 V AC to 18 V DC for the switched lamps. The large capacitor removes the ripple (noise) output from the bridge.
BR2 converts the 25 V AC to 34 V DC for the solenoids.
Turn off the power.
Note: These voltages are not regulated, so some variation is expected and is OK.
1) Connect the black lead of your voltmeter to the (-) minus of C1 and the red to the (+) plus side of C1. Turn back on the power. This voltage should be about 18 V DC. Switch the meter to AC and check. The voltage should be very low, 0.2 V AC or less is typical.
2) Leave the black lead on the (-) minus side of C1. Connect the red side to either the (+) output of BR2 (orange wires) or to CN1-2 or CN1-3 . This value should be about 34 V DC. Do not check for AC since there is not a capacitor here (although there is a small one on the power supply board).
Troubleshooting these Voltages
If the voltages are low, it is usually a bad (open) bridge rectifier. A shorted bridge will blow a fuse. Turn the power off. Disconnect the bridge and test it using the diode tester.
It is important to remove the bridge from the transformer when performing this test. The easiest way is to simply remove the fuse on the AC side of the rectifier. Also remove CN1 and CN2 from the Power Supply Board.
Power Supply Board
The power supply board creates the +12, -12, +5 VDC supplies that are critical to proper operation of the game. It also creates the very high and dangerous high voltages used for the displays.
Power Supply Versions
There were eight power supply versions used on Data East / Sega 3 and 3B systems. They can be broken down into three types:
Alpha Numeric Power Supply 520-5000-00
Playboy 35th, Time Machine, Torpedo Alley, Secret Service, ABC Monday Night Football, Back to the Future, Phantom of the Opera, Robo Cop, The Simpsons.
DMD (128 x 16) 520-5047-00
Batman (Data East), Checkpoint, Hook, Star Trek 25th Anniversary, Teenage Mutant Ninja Turtles.
DMD (128 x 32, ‘Normal’ Size) 520-5047-01 & 520-5047-02
Guns N Roses, Jurassic Park, Last Action Hero, Lethal Weapon 3, Rocky & Bullwinkle, Star Wars, Tales From the Crypt, Tommy, Wacky Gator, WWF Royal Rumble. This power supply has a more robust high voltage supply for the larger display.
DMD (128 x 64) 520-5047-03
Batman Forever, Baywatch, Mary Shelly’s Frankenstein, Maverick. There is no high voltage power supply for the larger DMD on this board. The power is generated by two separate boards. There is a separate +5 V DC and the high voltage is not generated on the Power Supply Board.
All versions have nearly identical +5, +12 and -12 volt DC circuits.
Note: If you have replaced the original displays with LED or LCD, then the high voltage section should be disabled by removing the proper fuse. On DMD power supply boards, these are F4 and F7. On Alpha Numeric displays, this is F3. Place a label stating that this fuse should not be replaced.
F7 on DMD displays just removes the center tap from the high voltage section of the transformer. There will still be high voltage present CN1-4 to CN1-7.
+/-12 and +5 Power Supply
In order to check voltages accurately, it is important to use the ground on the board under test.
F1 and F2 protect this supply. If either is blown, the machine will not operate.
1) Turn the machine off.
2) Connect the black lead to ground TP2.
3) Connect the red lead to TP1. Turn the machine on. Read 5.0 V DC (4.9 – 5.2, 4.8 is on the low side).
4) Connect the red lead to TP3. Read +12 V DC. This is unregulated, so it can be a bit low or high (10.5 to 13.5 or so).
5) +5V DC – 3J6 pins 7, 8, 9 or 10. +4.9 – 5.2V DC is OK.
+12V DC – Either side of F5 (this is unregulated so about 10 – 14V DC is OK).
Troubleshooting the +/-12 and 5 Voltages
Note that the DE/Sega circuit is nearly identical to the Williams System 11 circuit. Williams was nice enough to record the proper voltages on the circuit diagram which we have included above. If there are issues with the +5, it is helpful to measure and compare those voltages. Note: High voltages are nearby on this circuit board.
* If the +12 or -12 voltages are low, it can be a bad (open) bridge rectifier at DB1. A shorted bridge will blow a fuse. Test it using the diode tester. Also check for bad or cracked solder joints at this bridge rectifier on the board. When performing the diode test, disconnect the transformer by unplugging CN1.
* Inspect C4. If it is leaking or bulging, replace it. Later games replaced C4 with four 4700 MFD at C11 to C14. Those can also fail. Inspect for leakage or bulging. If one is bad, replace all four.
If the +12 V is OK, the problem is with the 5 V regulator.
The 5V supply is controlled by transistor TR5 and IC1. This is a pretty reliable system. However, if the 5V reads about 4.5V or so:
* Inspect / test C2, C3 and C7.
* C5 and C6 are a less likely to fail but should be inspected / tested.
Look for a leaking or deformed capacitor – although if not leaking / deformed, it does not mean it is good. Can also check with a capacitance meter. Some voltmeters have capacitance testing built in.
* If pins 12/11 are low on IC1, it is likely C8 or C7. This is a voltage doubler, so pins 12/11 on IC1 should be roughly double of TP1.
* If pin 10 of IC1 is OK, then it maybe TR5. If the +5 is still missing, test the transistor TR5.
* If one side of R6 has +5, but the other side is low, check C7. Less likely is a C6 failure.
* If the transistor is good, check pins 5, 4, & 3. If pin 5 is +5 and pins 4 or 3 are not, it is likely IC1.
If the -12 V is low or missing:
* Inspect C1. If it is leaking or bulging, replace it.
* Check the bridge rectifier (see above).
High Voltages – Display
High Voltages (see cautions). Note that there are not any test points for the high voltage supplies. It may be easier to measure these voltages at the plug on the display.
Alpha Numeric Displays
Alpha Numeric Display Measurements (all V DC):
Measured on the Display Board at CN4
#1 = -100
#3 = +100
#5 = Ground
#6 = +5
Measured on the Power Supply Board at CN5
#1 = Ground
#3 = -100
#4 = +100
#6 = 5
DMD Displays (Except the Largest 128 x 64)
DMD Pin Measurements (for all DMD games, all V DC):
#1 = – 110
#2 = -98
#3 = key, N/A
#4&5 = Ground (read nearly zero vs. Power Driver Board, but may get a very low reading)
#6 = +5 (4.9 – 5.2)
#7 = +12
#8 = +68
Power Supply Measurements (CN5)
#1 = Ground
#2 = -98
#3 = -110
#4 = +68
#5 = +12
#6 = +5
Troubleshooting the High Voltages
All these high voltage circuits used a similar design. The larger displays used more robust (higher current) transistors. In all cases, if either the plus (+) or minus (-) voltage is wrong or missing, turn off the power and check the resistance of the resistors. If off, you could try replacing them and see what happens. Otherwise, all of the major components in that section should be replaced. Both transistors (each half has two), and all of the diodes. The zener diodes are especially prone to fail. Note that the (+) side (+68) and the (-) side (-110 & -98) are separate. If only one side is out, it might be necessary to replace only the components in that side.
Great Plains Electronics used to sell rebuild kits for these supplies, but, as of 2022, no longer do. However, their parts list serve as a great guide. Here is a checklist for Williams high voltage power supplies from GPE. It can be used as a rebuild guide, but be careful to compare the parts listed to those on your power supply board and substitute as needed. The alpha numeric power supplies used very different components than the DMD high voltage supplies. And the smaller DMD games had different components from the larger DMD. And the 128 x 64 (largest) DMDs were altogether different.
Only the DMD supplies have a +12 volt supply. That design is fairly simple. Check insure that there is voltage coming into VR1. Use fuse F4 as a test point (check both sides). If that checks good, but not at the output, then VR1 has likely failed. The two small electrolytic capacitors C15 and C14 can also fail, so check them for leakage, damage, or if they are shorted and replace as needed. If you have a capacitance tester, now is the time to use it.
If there are problems with the high voltage power supply, the best options are to either 1) buy a new aftermarket board, or 2) replace the plasma displays with modern LED displays that do not require the high voltage. We prefer replacing the displays since the original ones are nearing the end of their useful life. If you decide to remove the original displays for LED, be sure to remove the fuse(s) to this high voltage section.
Other Voltages – Controlled Lamps & Solenoids
There are two power supplies not on the power supply board: switched lamps +18 VDC and +34 VDC for some of the solenoids.
Those power supplies consist of two fuses, both 8A Slo Blo (slow blow), two rectifiers and one large capacitor. See “Off the Boards Backbox Voltages” section above.
If either of those 8A fuses blow, then it is likely that the rectifier needs to be replaced. To test, turn off the machine, remove the 8A fuse, unplug CN1 on the Power Supply board, then test the rectifier.
The large capacitor is for the switched playfield lamps. That usually does not fail by shorting. It usually loses capacitance which would increase the AC to the lamps.
The Power Supply Board also passes the DC voltages from those backbox bridge rectifiers, through fuses and then back out. There is almost nothing that can go wrong there, other than a bad fuse holder or a bad connector.
If the fuse on the power supply board blows, it could be a shorted bulb, shorted socket or a wiring issue. If the fuse for the low voltage solenoid blows, it could be a locked on solenoid, shorted coil or diode.
The solenoid voltage does include two small capacitors on the power supply board. C8 is a 150 uF electrolytic cap that should be inspected. If it appears damaged, has leaked, or is otherwise deformed, replace it.
Oddly, DE/Sega included a Z1 on the board that appears to be a Zener diode but it is not. As best we can tell, it is Metal Oxide Varistor (MOV) also sometimes called a Varistor. If it is defective, it could be removed, but it may be a good idea to replace it with a 47 Volt MOV V47ZT1.
PBB Power Supply
The PBB supply serves several functions, from providing fuses for the GI lamps, switching between solenoids and flashers, high power drivers for certain solenoids and a relay to turn on and off solenoids.
But the function we are looking at here is the flipper power supply. The flippers use 50 V DC and it is generated here. 48 VAC comes in from the transformer, BR1 is the bridge, located on this board, that converts it to 50 V DC. There is a small electrolytic cap C1 which is 100 uF 250 V. There are a few differences in the connectors between generations of boards, but, other than that, the circuit is pretty much the same.
Measuring the Voltage
There are not any test points on this board. The voltage can be measured at J7 or at the flipper coils.
Note that the 50 V DC may measure higher than 50, perhaps as high as 70 V DC. That is because the power is not under load and capacitor C1.
Not much can go wrong other than the bridge and C1. If the bridge rectifier opens up, then the voltage will drop. If it shorts, the fuse will blow. Disconnect the bridge and test it using the diode tester. Be sure to disconnect the bridge from the transformer when performing this test. Either remove J4 or remove the 5A SB fuse going to this bridge.
If C1 leaks, it can cause the flippers to be weak or the fuse to blow. Connectors could burn or be damaged, but this is more likely with GI connectors.
Data East Power Supply Corrosion Repair – Troubleshooting a leaking capacitor.
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