3 Technical Info
3.1 MPU Board
Bally 6803 MPU Board
The Bally 6803 MPU incorporates all of the function of it's predecessors, the -17 and -35 MPUs, along with lamp and solenoid drive circuitry. The MPU is responsible for driving all game features other than sound, which is handled by one of several sound boards used in the 6803 game system run.
Architecturally, the board is similar to it's predecessors but employs the 6803 microprocessor along with two 6821 Peripheral Interface Adapters. It also contains what is essentially the entire lamp board circuitry along the left side of the board, including the familiar 4514 demultiplexers, 2N5064 SCRs and MCR-106 SCRs (silicon controlled rectifiers). Along the top of the MPU board, the solenoid driver circuitry of the older Bally Regulator/Solenoid Driver Board has been incorporated, including the typical 74LS154 4-to-16 decoder, CA3081 transistor arrays, and TIP-102 transistors. A "cube" relay, located in the upper right corner of the MPU, is used to complete the power circuit for the flippers and is energized only when a game is in play. 3.1.1 CPU Board ROM Info and Jumper Settings
Game U2 U3 Jumpers
Eight Ball Champ Not Used 0B38-00803-0005 2, 4, 6, 8, 10
Beat the Clock* Not Used 0C70-00803-0005 2, 4, 6, 9, 10
Lady Luck Not Used 0E34-00803-0005 2, 4, 6, 8, 10
Motor Dome E14A-42AAE-BX40 E14A-42AAE-CX4D 2, 4, 6, 8, 10
Black Belt 0E52-00803-0001 0E52-00803-0002 2, 4, 6, 8, 10
Special Force 0E47-00803-0004 0E47-00803-0005 2, 4, 6, 9, 10
Strange Science 0E35-00803-0001 0E35-00803-0002 2, 4, 6, 9, 10
City Slicker 0E79-00803-0002 0E79-00803-0003 2, 4, 6, 9, 10
Hard Body E94A-12601-0000 E94A-12602-0000 2, 4, 6, 9, 10
Party Animal H01A-12601-0000 H01A-12602-0000 2, 4, 6, 9, 10
Heavy Metal Meltdown H03A-12601-0000 H03A-12602-0000 2, 4, 6, 9, 10
Dungeons & Dragons H06A-12601-0000 H06A-12602-0000 2, 4, 6, 9, 10
Escape from the Lost World H05A-12601-0000 H05A-12602-0000 2, 4, 6, 8, 10
Blackwater 100 H07A-12601-0000 H07A-12602-0000 2, 4, 6, 9, 10
Truck Stop H08A-12601-0000 H08A-12602-0000 2, 4, 6, 9, 10
Atlantis 2006-12601-0000 2006-12602-0000 2, 4, 6, 9, 10
*Beat the Clock manual may state W8 in, W9 out. However, there was a service bulletin after the game was released stating the opposite.3.2 Power Supply Board
The power supply board from a 6803 based Bally game.
Solder joints on the single sided board are subject to fracture.
The Bally 6803 game system power supply board provides all of the voltages necessary to operate the game. Solder joints, as shown on the right are subject to fracture on the power supply board, especially since it's a single sided board. Reflowing these solder joints will solve many power problems. 3.3 Sound Boards
3.3.1 Squawk & Talk
Bally Squawk & Talk Sound Board
3.3.2 Cheap Squeak Sound Board
Bally Cheap Squeak Sound Board A080-91603-XXXX or Midway P/N M-051-00114-XXXX
The Cheap Squeak was designed as a lesser expensive sound board. It only utilizes a 6803 microprocessor, which allows it to function without 6821 PIAs and external RAM memory. This sound board is only capable of simple tones and sounds, but not speech. Although the Cheap Squeak is used in a handful of -35 based Bally games, Lady Luck is the only 6803 based game which uses it.
At power up, the Cheap Squeak's LED will flicker briefly, then flash, flash again, then turn on and stay on. Once the LED stays on, it seems to turn itself off for certain sounds, and then turn back on. Likewise, it appears to idle with the LED on, when no sounds are playing. The LED May turn on and off when sounds are playing or idle, but this is not always the case.
With Lady Luck, upon pressing the self test button (SW1), the sound board will play an explosion type noise. The board will then reboot itself.
Board Theory of Operations
The 6803 (U1) microprocessor multiplexes A0-A7 with D0-D7, calling those signals AD0-AD7. The processor fetches information from the sound ROMs (both code to execute and sound clips) by placing address information on AD0-AD7 and strobing the processor's AS (address strobe) signal to the 74LS373 (U2), thereby latching the lower 8 bits of the address bus in the LS373. A8-A15 are used along with jumpers JW1 through JW12, to implement a memory mapped I/O scheme to address the 2 sound ROMs which can be 2532s, 2732s, or 2764s. A14 and A15 control the 74LS10 (a triple 3-input nand gate) to assert device selects to the ROMs.
Note that the processor does not use the traditional R/W signal as it never "writes" to memory. Besides placing instruction address and data on the address and data busses, the processor reads sound selects via P20-P24 and writes sound data to the DAC via P10-P17. Think of these lines as PA1-PA7 of a 6821 or 6532.
The 6803 is initialized by the MPU at power up into 6803 mode N. Once initialized and running, the sound ROM code running in the 6803 accepts sound signal commands and merely reads pre-formatted sound "clips" from the sound ROMs and then writes the data to the ZN429 (U6) digital-to-analog converter (DAC) 8 bits at a time. The DAC converts the digital data to an analog level which is presented to the amplifiers for output to the speaker(s).
The board creates 5VDC on board by regulating 12VDC down to 5VDC. Unregulated 12VDC enters the board at J1-10. It is filtered by C8, C9, and C10. The inductor at L1 smooths the voltage somewhat. D6 (VR332, equivalent to a 1N5402), D7, and D8 drop the voltage by .5 - .7 volts (normal voltage drop across a diode). The 7805 at U9 further regulates the voltage down to 5VDC which can be measured at TP2 (TP3 is ground).
This 5VDC is used as a reference voltage by the amplifiers as well as to power the TTL logic ICs. The ZN429 DAC also uses this 5VDC as a voltage reference. To prevent the sound volume from fluctuating over the range of operating temperatures, the reference voltage is held constant by a "voltage divider biasing circuit" comprised of resistors at R22, R23, and R24, and a 2N5305 NPN transistor at Q7. This reference voltage is presented at pin 5 of the DAC.
TP1 should measure about 11VDC.
TP2 is 5VDC.
TP3 is ground.
TP4 is the clock signal, provided externally by the 6803 for the purpose of synchronizing address and data read cycles.
TP5 is the reset signal, which is also present on pin 6 of the 6803.
Bally Cheap Squeak Sound Board with Jumpers Highlighted
Jumpers JW2, JW4, JW7, JW10, and JW11 should be installed when U3 EPROM is installed for Lady Luck.
3.3.3 Turbo Cheap Squeak (T.C.S.)
The Bally Turbo Cheap Squeak (T.C.S.) Sound Board. Note that the headers, which are normally individual pins soldered directly to the board, have been replaced on this board. The test switch is also broken on this board.
The Turbo Cheap Squeak sound board was used on games like Strange Science and Motordome. The sounds it can produce are pretty basic.
The board features a 68B09EP processor, a 6821 PIA, 16K of static ram, and 256K of ROM. It interfaces to the MPU similarly to the Bally Squawk and Talk board. Volume is controlled by the pot at VR1.
Note that the board is marked "T.C.S. FOR PINBALL". Some Bally / Midway video games also use a Turbo Cheap Squeak sound board. The T.C.S. sound boards used for video games and pinball are not 1-to-1 compatible between one another.
The following games use the Cheap Squeak:
Black Belt / Karate Kick
Normal boot up diagnostics via the LED for the T.C.S is as follows:
1st Flash - Determines if the external ROM (U7) is good.
2nd Flash - Checks if the external RAM (U6) is good.
3rd Flash - Checks the 6821 PIA (U8).
3.3.4 Sounds Deluxe
Bally Sounds Deluxe Sound Board3.4 Trough Optos
4 Opto Trough Transmitter Board
4 Opto Trough Receiver Board
Starting with Dungeons & Dragons, some 6803 series games used infared (IR) optic sensors for the trough switches. The more common transmitter and receiver boards used a total of 4 optic sensors. Escape from the Lost World only used a dual optic sensor transmitter and receiver. Blackwater 100 and Truck Stop used a 4 sensor board. Atlantis did not use an optic sensor board, but instead had a trough assembly with switches very much like Williams System 11 games.
The transmitter board consists of Motorola MLED930 IR emitters and current limiting resistors (68 ohm 1/2 watt). The receiver board consists Motorola MRD370 IR light detectors, 2N3904 transistors, and 390 Kohm 1/4 watt resistors. The transmitter board is powered by +5VDC. 3.5 Accessing Bookkeeping, Settings, and Diagnostics
6803 coin door test button
The single black button shown on the right side of the picture (just above the volume pot) causes the game to enter audits/diagnostics mode. All subsequent control of the game audits/diagnostics is done using the keypad (see below) in most cases. Some of the later 6803 games, such as Escape from the Lost World and Blackwater 100 abandoned the use of the keypad. Flipper buttons, auxiliary buttons (located below the flipper buttons) in combination with the start button are used to advance through bookkeeping, settings, and diagnostics.
On some earlier games, if the game detects a "stuck switch", it will make a hugely annoying sound until the stuck switch condition is corrected. Advice: turn the volume down. Later games would advance to attract mode regardless of stuck / closed switches.
3.5.1 6803 Keypad
The "beloved" 6803 keypad
As easy as "A, B, C"... Bally attemped to improve the operator's interface to the game system with this poorly constructed keypad. The keypad can be used to set free play, what kind of sounds are desired, balls per game, etc. See your game manual for game specific information.
The settings can be rather counter intuitive. For instance, setting (or register as it's called in the manual) 42 allows the operator to set the game to free play by entering "65".
Setting 27 allows the operator to configure the game sound style. Usually, you'll want this set to "3" which causes a "noise" effect when scoring occurs and enables background sound.
3.5.2 Built In Tests
Using the keypad to enter the following values begins the associated test. What could be more logical?
90 - Lamp Test
91 - Display Test
92 - Solenoid Test
93 - Sound Test
94 - Stuck Switch Test