Bally 6803
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1 Introduction
The Bally 6803 game system, and the games themselves, were developed with extreme cost consciousness in mind. Bally used particle board cabinets with minimal artwork, backglasses illuminated by a single 115VAC light bulb, cheaper materials and short cut techniques during these years of game development. Still, many of these games continue to be enjoyed by hobbyists now and will be for years to come.
As seen in these pictures, the backbox configuration generally consisted of the game transformer, a power conditioning board (lower right), a sound board (upper left), and a new 6803 processor based MPU board that integrated all game control functions previously found on on Bally -17/-35 MPU boards, lamp driver boards, and solenoid driver boards, onto a single MPU board.
2 Games
| Game Title | Game Number | Sound | Displays | Transformer | Keypad Used | Notes |
|---|---|---|---|---|---|---|
| Eight Ball Champ | 0B38 | Squawk & Talk | 4 7-Digit / 1 6-Digit | Yes | ||
| Beat the Clock | 0C70 | Squawk & Talk | 4 7-Digit / 1 6-Digit | Yes | ||
| Lady Luck | 0E34 | Cheap Squeak | 4 7-Digit / 1 6-Digit | Assumed Yes | ||
| Motordome | 0E14 | T. C. S. | 2 "Special" 14-Alphnumeric | Yes | ||
| Black Belt | 0E52 | T. C. S. | 2 "Special" 14-Alphnumeric | Assumed Yes | ||
| Special Force | 0E47 | Sounds Deluxe | 2 "Special" 14-Alphnumeric | Yes | ||
| Strange Science | 0E35 | T. C. S. | 2 "Special" 14-Alphnumeric | Yes | ||
| City Slicker | 0E79 | T. C. S. | 2 "Special" 14-Alphnumeric | Yes | ||
| Hardbody | 0E94 | T. C. S. | 2 "Special" 14-Alphnumeric | Yes | ||
| Party Animal | 0H01 | Sounds Deluxe | 2 "Special" 14-Alphnumeric | Yes | ||
| Heavy Metal Meltdown | 0H03 | Sounds Deluxe | 2 "Special" 14-Alphnumeric | Yes | ||
| Dungeons & Dragons | 0H06 | Sounds Deluxe | 2 "Special" 14-Alphnumeric | Yes | ||
| Escape from the Lost World | 0H05 | Sounds Deluxe | 2 "Special" 14-Alphnumeric | No | ||
| Blackwater 100 | 0H07 | Sounds Deluxe | 2 "Special" 14-Alphnumeric | No | ||
| Truck Stop | 2001 | D-11581-2001 | 2 "Special" 14-Alphnumeric | No | Uses a sound interface board to process signals for sound board | |
| Atlantis | 2006 | D-11581-2006 | 2 "Special" 14-Alphnumeric | 5610-12136-00 or 5610-12393-00 | No | Uses a sound interface board to process signals for sound board |
Game model numbers provided by the Internet Pinball Database - http://www.ipdb.org
NOTE: Not to be mistaken with the video game Turbo Cheap Squeak, which does not have on board amplification, the pinball Turbo Cheap Squeak is referred to as the T. C. S. sound board.
3 Documentation
3.1 Manuals & Schematics
The owner's manual is a handy resource to have for game settings and audit information. Schematics for each game are essential in tracing down connections to lamps, switches, and solenoids.
3.2 Parts Catalogs
Parts catalogs can also be useful, which include part numbers (helpful for purchasing parts online), exploded views of assemblies (helpful to see how the assemblies are put together), and board layouts & parts lists, and diagrams for controlled lamp, solenoid, and rubber locations. Online copies of Bally parts catalogs can be found on Planetary Pinball.
| Catalog | Cover | Source | Games | Notes |
|---|---|---|---|---|
| Bally/Midway 1986 Parts Catalog | Viewer | Beat the Clock, Hot Shotz, Eight Ball Champ, Lady Luck, Motordome, Black Belt, Karate Fight, Special Force, Strange Science | Exploded views and parts lists of common assemblies, such as flippers, kickers, drop targets, slingshots, and more. Cabinet parts included. Circuit board layouts & parts lists. No game-specific information or playfield diagrams included. | |
| Bally Pinball Game Playfield Parts Guide - 1987 | Viewer | Motordome, Black Belt, Special Force, Strange Science, City Slicker, Hardbody, Party Animal, Heavy Metal Meltdown | Playfield diagrams (both of the top side and bottom side) listing parts and assemblies. However, rubber placement and switch/solenoid designations are not included. | |
| Bally 1987 Pinball Pinball Game Common Assemblies | Viewer | Motordome, Black Belt, Special Force, Strange Science, City Slicker, Hardbody, Party Animal, Heavy Metal Meltdown | Exploded views and parts lists of common assemblies, such as flippers, kickers, drop targets, slingshots, and more. Cabinet parts and display board parts are also listed.
|
3.3 Service Bulletins
Supplementary service bulletin books were released, which included service bulletins that detailed any problems or issues with games that were discovered after they were released.
| Manufacturer | Version | Cover | Source | Games | Notes |
|---|---|---|---|---|---|
| Bally | Service Bulletin Book, 1987 | Cybernaut, Eight Ball Champ, Motordome, Black Belt, Strange Science, Hardbody | Also contains some later classic Bally games (-35 MPU) | ||
| Bally | Service Bulletin Book, 1988 | Beat the Clock, Motordome, Black Belt, Strange Science, Hardbody, Party Animal, Heavy Metal |
|
4 Technical Info
4.1 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.
4.1.1 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.
4.2 Power Supply Board
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.
4.3 Sound Boards
4.3.1 Squawk & Talk
The Bally Squawk and Talk board, so widely used in -35 MPU games, was also used in several 6803 games like "8 Ball Champ" for instance.
4.3.2 Cheap Squeak Sound Board
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.
Test Points
- 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.
Jumpers JW2, JW4, JW7, JW10, and JW11 should be installed when U3 EPROM is installed for Lady Luck.
4.3.3 Turbo Cheap Squeak (T.C.S.)
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:
- Motordome
- Black Belt / Karate Kick
- Strange Science
- City Slicker
- Hardbody
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).
4.3.4 Sounds Deluxe
4.4 Trough Optos
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.
4.5 Accessing Bookkeeping, Settings, and Diagnostics
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.
4.5.1 6803 Keypad and Built-In Tests
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 42 (or register 42 as it's called in the manual) 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.
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
4.6 Solenoids
5 Problems and Fixes
5.1 Power Problems
The Bally 6803 game system power supply board provides all of the voltages necessary to operate the game.
The 190VDC display voltage is derived from 170VAC input via the same circuitry as was used by the prior generation regulator/solenoid driver board. All of the same practices apply to this board including replacing the 25Kohm trim pot. The power supply shown at left has had the failed 160uf/350V high voltage filter cap replaced.
The board shown at left still has the original 3/4 inch fuse in the high voltage section. When necessary, it's easy and advised to modify the board to accept the more common 1.25 inch fuses as shown here.
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 and is highly recommended.
The 5VDC logic voltage is derived from 9.4VAC input, again using similar circuitry to the prior generation regulator/solenoid driver board. It's good practice to replace the 11,000uf/25V cap with a similar value. 12,000uf caps are a good choice. Here, a 15,000uf cap was used which also works fine.
The board also rectifies 49VAC to about 43VDC (probably a bit more) for use in solenoid circuits. General Illumination power (6.3VAC) also passes through the board, fused by two 15AFB fuses at FU6 and FU7.
5.1.1 Fuses and Test Points
The following table lists the circuit protection fuses for each circuit on the power supply.
FU1 - Solenoid Power - 5A SB (2 flippers), 6ASB (3 flippers), 7ASB (4 flippers)
FU2 - Display Power - 3/4A FB (a 3/4 inch fuse from the factory...suggest revising the power board to accept 1.25" fuses)
FU3 - 5V Logic Power - 6A SB
FU4, FU5 - 20VAC Controlled Lamp Power - 8A SB
FU6, FU7 - 6.3VAC General Illumination - 15A FB
The following test points are available on the power supply.
TP1 - 5VDC
TP2 - 190VDC, adjustable via the trim pot
TP3 - 230VDC, unregulated
TP4 - 43VDC
TP5 - 14VDC, unregulated
TP6 - 11VAC
TP7 - 11VAC
TP8 - 6.3VAC
TP9 - 6.3VAC
TP10 - Ground
5.2 MPU Issues
5.2.1 Relocating the Factory NiCad Battery off the MPU
Like other Bally and Stern MPUs that employ a battery on the MPU to provide power to the volatile RAM, it's a good idea to remotely locate the battery. The 6803 MPU provides an excellent place to locate a blocking diode so that the MPU charging circuit is blocked from attempting to charge the alkaline batteries. In the picture at left, two holes were drilled in the fat trace leading from the positive battery connection to the northwest. That trace was severed under the diode where the black line is shown, and the diode soldered across the severed trace with the banded end pointing away from the positive connection on the board. Be sure to provide enough wire to allow the remote holder to reach the bottom of the head making it impossible for leaky batteries to drip on the circuit boards.
5.2.2 Leon's 6803 CPU Repair
Leon's 6803 repair procedure has been added to the PinWiki, and can be found here.
5.2.3 Replacing header pins
Bally 6803 header pins are different from every other game system header pins. Bally used pins without a "carrier". Over time, the plating on these pins fails, creating conductivity issues. These header pins can be replaced fairly easily. Simply heat each pin individually and remove them. It's best to heat the pin itself versus the pin/board junction as quite a bit of heat is required to remove the pins, which are "jammed" into the board. Installing a new strip of .100 pins may require a bit of tapping with a hammer as the new pins are larger in diameter.
The same procedure may be used for .156 header pins on the MPU, as shown at left.
5.3 Solenoid Problems
5.3.1 General Solenoid Debugging Info
Bally 6803 game solenoids are driven from the row of TIP-102 transistors on the top edge of the master control board.
If one of these TIP-102s shorts, the coil/flasher will lock on, heat up, and eventually fail. When a TIP-102 is found to be shorted, examine the associated coil/flasher for shorts. Replace as necessary. Note that a coil resistance should never measure lower than 2 ohms.
The drive circuit for solenoids/flashers is...
- The 6803 processor programs the 6821 PIA at U7 output signals at PB0 - PB3 (called PB10- PB13 on the craptastic schematics)
- The 6803 processor programs the 6821 PIA at U7 to pulse pin 19, CB2 (called CB12) enabling the chips select signal of U14
- Multiplexed (4 bits, PB10 - PB13) solenoid data presented at U14 (a 74LS154 4-to-16 decoder) is decoded when the chip select signal is enabled
- The decoder pulls the commanded signal (M0 - M14) to ground
- The ground passes through a 1.2K resistor on it's way to the base of a CA3081 integrated transistor array (U19 and U20), turning the transistor off
- With the CA3081 transistor turned off, power is then routed to the base of the TIP-102 (SE9302 Bally part number) turning it on and allowing coil power to conduct to ground and the coil to pull in or the flasher to turn on
A .002uf ceramic disk capacitor is incorporated across the collector and base of each TIP-102. On rare occasion, these capacitors can short causing the transistor to turn on and the coil/flasher to lock on. With the transistor removed, resistance between the center and top leg (ground) of each TIP-102 should be infinite (open). If resistance is anything other than infinite, there is a good chance that the ceramic capacitor is shorted.
TIP-102 transistors are easy to test.
- Set a DMM to diode check (the symbol looks like this -|<- )
- Black probe on transistor tab or center leg (they are connected internally)
- Red probe on each flanking leg one at a time
- A reading of .4 - .7 volts should be seen.
- Readings outside of these values indicate that the transistor has failed
Testing the CA3081 transistor arrays is simple also.
- Set a DMM to diode check (the symbol looks like this -|<- )
- Red probe on pin 15 of the IC
- Black on pins 1, 2, 4, 7, 9, 12 and 14 should read about .250
- Black on pins 3, 6, 8, 10, 11, 13 and 16 should read about 1.800
- Black on pin 5 will read shorted
- Readings outside of these values indicate that the transistor array has failed
5.3.2 Slingshots Inoperative
Be advised that some 6803 games (perhaps all) have a setting, in "Basic Settings", to turn slingshots on or off during game play. If the slingshot switches register by scoring in game play or during switch test, and the slingshot solenoids fire in test but not in gameplay, examine this setting. 0 = Off during game play, 1 = On during game play.
5.4 Lamp Problems
Like the prior game system, Bally 6803 games did not use a lamp matrix. All controlled lamps are turned on via SCRs (silicon controlled rectifiers, either 2N5060s or MCR-106s) on the MPU board. The SCRs on the MPU must be refreshed (turned on) at 60Hz since SCRs turn off when the AC sine wave passes through zero (called the zero cross).
The usual techniques for dealing with lamp problems should be employed.
Lamp always on
It's probable that the associated SCR is shorted on.
Lamp never on
Verify that the lamp is good by testing it in a working socket (like the backbox).
Verify that the lamp socket is good by jumping from a known good lamp socket to the suspect socket. If the lamp then lights, the socket and bulb are good.
Verify that the wire has not been severed by "buzzing" between the lamp socket and the associated lamp drive connector on the MPU.
Verify that the connector is working correctly by "buzzing" from the associated lamp drive SCR on the MPU to the lamp socket.
Test the SCR using the diode test.
Verify that the SCR is being turned on by the 4514.
Lamp sockets
In an effort to cut costs, the lamp socket style shown at left was used across quite a bit of the production run. While the "Spacer Invaders" era lamp sockets were bad, this style was even worse. Once a tab breaks off, it's not cost effective to repair them. Simply replace them with a new socket of the more conventional 3 tab style.
5.5 Switch Problems
5.6 Display Problems
5.6.1 Flickering Displays
Displays that form the characters properly, yet flicker at something like a 50% duty cycle (on half the time, off half the time) are sometimes caused by low high voltage DC.
Nominal display voltage is 190VDC but this voltage can be "trimmed" down using the trim pot. Doing so has the advantage of extending the life of the plasma displays. Measure DC voltage at TP2 as you trim the voltage, to at least ensure that the voltage isn't being turned up. At some point (well below that level), the displays will begin to flicker.
Sometimes the root cause of the reduced voltage is a failed or open HV filter cap. The OEM HV filter cap which was originally a 160uf/350V cap, can be replaced by a commonly available 150uf/350V cap.
One very unusual reason for flickering displays is caused when the outhole switch "fish paper" becomes dislodged and allows the switch blade(s) to touch game ground. The behavior caused is different from the flicker caused by low high voltage discussed above. This flicker generally manifests on the left display and the segments lit do not form characters but seemingly random "noise". This anomaly occurs when the ball is in the outhole, and the playfield is positioned in its normal state (not propped up).
5.7 Sound Problems
5.7.1 Sounds Deluxe Board
This sound board has a common problem with DAC failure which is described in a Bally Service Bulletin. The failure can be prevented easily by removing the 47uf electrolytic capacitor at C12. Simply clip both of it's legs. Removing the capacitor seems to have no adverse affect while preventing a voltage condition on power down that can destroy the DAC. Since the AD7533 chip is getting harder to find and costlier to replace, making this change is strongly advised.
The LED will flash at power on indicating test status. Completing 6 flashes means that the ROMS, RAM, and PIA have completed test successfully.
Flash numbers and meaning
- Flash 1 - The program ROM at U11 has passed checksum test.
- Flash 2 - The program ROM at U12 has passed checksum test.
- Flash 3 - The program ROM at U13 has passed checksum test.
- Flash 4 - The program ROM at U14 has passed checksum test.
- Flash 5 - Both 6116 (or 6264s if strapped for them) have tested good.
- Flash 6 - The 6821 PIA at U7 has tested good.
The pinout for the Bally Sounds Deluxe board is shown at left. The board can be booted on the bench with a 12VDC power supply. Connect 12VDC to pin 10. Connect all pins labeled ground together along with pin 15, which the manual labels "unregulated 14VDC return", which is another ground. Connect the power supply ground to any of the ground pins or to TP2 (GND).
If the 7805 voltage regulator on the board is working properly, measuring DC voltage between TP1 (5VDC) and TP2 should yield 5VDC.
The sound interface to the board is deceptively simple. Grounding pin 8 interrupts the big, powerful 68000 microprocessor on the board which reads the sound select inputs presented on pins 1 through 4 via the 6821 PIA at U7. Grounding pins 1 through 4, and then grounding pin 8 will generally produce sound. However, the interface isn't as simple as a 1 of 15 sound select, the maximum number of unique sound select bit patterns that 4 bits can define. Like the Squawk and Talk board, the interface uses a "command followed by command" design. Deciphering the actual interface might be quite a chore.
General troubleshooting
- As with all of these old Bally sound boards, replacing the electrolytic caps is a good place to start.
- Replace the 10K ohm volume pot
- Test the socketed 6821 PIA at U7
- Test the socketed RAM memory
- Verify the ROM images are correct
- Verify DC voltage between test TP1 (5VDC) and TP2 (GND) is 5VDC
- Verify DC voltage at the positive lead of the 4700uf cap is about 14VDC
- Pressing the red button should play a game tune, which may vary with each press of the button
5.8 Flipper Problems
5.9 Coins Register But Don't Credit Up
This is commonly seen on VPinMAME emulation, but applies to real life as well.
Coins drop OK, switch is good, game makes noise, but it remains on "Credits 0" and doesn't credit up.
Symptom is corrupted/blank NVRAM.
To fix, open coin door (make sure coin door switch is working, otherwise the keypad won't work), then do these steps:
Hit "Test", to enter operator mode.
Hit "A" until "Feature Options" is displayed.
Hit Enter.
It will say "Reset Factory Is".
Hit 6, then 5, then Enter.
Hit "Game" to return to attract mode. You'll know it worked because it will take longer than usual to reach attract mode, and the display will flicker slightly as the computer clears the memory (this is normal).
Intuitive and easy to remember, right? And Bally had the nerve to advertise "manual-free testing"....
6 Game Specific Problems and Fixes
Example would be servo controller on Independence Day pinball
7 Repair Logs
Did you do a repair? Log it here as a possible solution for others.