Schematics For Hard Drivin'/Race Drivin' ADSP, Motor Amplifier, and DSK Boards

    Because the schematics for several of the boards used in Hard Drivin'/Race Drivin' were not published in the game manuals I am posting them here.

    The original schematics were B Size (11"x17") so I am posting each one as two 8.5"x11" sheets. The left side of the sheet is first, followed by the right side.

    I regret that I am not able to provide very much in the way of support for people wanting to troubleshoot their boards.

Jed Margolin
March 9, 2002

ADSP Board

    The ADSP Board uses an Analog Devices ADSP-2100 in a Pin-Grid Array (PGA) package.

    The ADSP II Board is identical to the ADSP Board except it uses the ADSP-2100 in the Plastic-Quad-Flat-Pack (PQFP) package.

    ADSP and ADSP II Boards are electrically and mechanically equivalent.

ADSP Board (2.6 MB PDF)

DSK Board

    The DSK (Driver Speed Kit) Board was used in Race Drivin' only. It contains an AT&T DSP32 Floating Point DSP (ASIC61) to provide for a better car model, as well as extra RAM and ROM, and a Texas Instruments TMS320P15 single-chip DSP (ASIC65) for extra security. Atari called the DSP32C and TMS320P15 ASICxx  (or in some places (PLDxx) to  disguise the fact that they were commercially available ICs. I doubt it fooled anyone.

    The DSP32C  was originally made by AT&T for their in-house use. Then they started selling it outside the company. Then they spun off their semiconductor business into Lucent Technologies. They seem to have spun off DSPs into a company called Agere. Unfortunately, the DSP32C seems to have been discontinued and an Interent search has failed to come up with a data sheet for it.  (The description of just the instructions is a good-sized book.)

    The TMS320P15 was (is?) a single-chip version of the TMS32010, the first successful DSP. It had internal EPROM protected by a security bit. Once the security bit was programmed you were not supposed to be able to dump the contents of the EPROM. In the part with a window you could only erase the Security Bit by erasing the EPROM program. We used the part without a window so it could not be erased. (The OTP version was also lots cheaper.)

    If you ground pin 4 on the TMS320P15 (signal 'P2') and then reset the chip (turning the game off for a few seconds and then turning it on again will do the trick) the TMS320P15 will send the Atari Games copyright message in Morse code which can be received on a standard AM radio by holding it near the DSK Board. Tune around the AM band to get the best quality signal.

    I added this to my Self-Test code so that, in the event Race Drivin' was pirated I would be able to tell if the program in the TMS320P15 had been reverse engineered or if the chip's security feature had been hacked. (The Morse code program is not accessible from the game code.)

    As far as I know, Race Drivin' was never pirated, although Hard Drivin' was.

    The TMS320P15 was used in another game (Road Riot) that was pirated. When I checked for the Morse code program in the pirated game, it was played loud and clear. So much for Texas Instrument's claim that the chip's security was actually worth a damn.

DSK Board (1.31 MB PDF)

Motor Amplifier

    After several months looking for a real copy of the Motor Amp, I finally found it! This is the Motor Amp used in the Cockpit versions of Hard Drivin' and Race Drivin'.

    The Steering Assembly Troubleshooting Guide in the Hard Drivin' and Race Drivin' game manuals helps you narrow down problems to either the Motor or the Motor Amp and then instructs you to contact Atari Customer Service. That is no longer an option since Atari Games no longer exists except as a game development group for home games. It isn't even called Atari Games; it's called Midway Games West.

    First a warning.

    The voltages used in the Motor and in the Motor Amp are hazardous.Unless you are experienced working with High Voltages, Don't Try to Fix it Yourself. (You really can kill yourself.) In addition, parts of the Motor Amp are NOT isolated from the power line. Working on these parts of the Motor Amp (especially using line-powered equipment like an oscilloscope) requires the use of an isolation transformer. Because the Motor can draw a Lot of current, the isolation transformer has to be a Big Mother. (Variacs are generally Not isolated.) It's not worth getting injured or killed over a video game.

    The Motor Amp is interfaced to the game board through the use of opto-isolators in the digital lines. The Motor Amp board was designed to meet U.L. safety standards for high voltage products.

    Start by checking the usual suspects (blown fuses, charred components, the smell of smoke, etc.) as well as whether the Force-Feedback has been turned off in the Disable Broken Controls screen in the Test Menu.

    The next thing is to determine if the problem is with the Motor, the Motor Amp, the Motor Position Pot, or the A/Ds.

    There is a screen in the Test Menu (Special Functions > Main Board Controls > Steering Wheel) that allows you to select various Motor tests that operate open-loop and do not use the position pot.

    If these tests work, you know the problem is not with the Motor or the Motor Amp.

    There are other screens to read the pots. The Motor position is read by both the 12-bit A/D and the 8-bit A/D. Both must be working or the program knows there is a problem and turns off the Force-Feedback Steering.

    There is also an Operator option to turn off Force-Feedback Steering in Disable Broken Controls.

    If the Steering Wheel Tests don't move the Motor, the problem is either with the Motor or the Motor Amp.

1.  Make sure  the ribbon cable is plugged in correctly with Pin 1 of J15 on the Main Board going to Pin 1 of J6 on the Motor Amp Board.

2. There are jumpers on the Motor Amp Board in case we wanted to operate more than one Motor Amp (I don't think we ever did.) In order for it to work in the game, the jumper must be installed in E1 (the one closest to the connector).

3. A voltmeter across the Motor should tell you if the Motor Amp is producing drive for the Motor. (The Send-Force Tests can be used to output a steady drive.)

4.   A good way to test the Motor is to connect a DC voltage across it. (Disconnect it from the Motor Amp first.) I believe the motor is either a 60VDC or a  90VDC motor. However, since 60VDC (or 90VDC) produces full torque. I would guess something lower would work. A 24VAC transformer, when half-wave or full-wave rectified and filtered, will produce about 36VDC. That should be enough to test the Motor. (I would guess a 1000 uF filter capacitor would be sufficient.)

    Note that if you rectify and filter the 120VAC line you will get about 160 VDC. That is *way* too much for the Motor.

    The motor is a DC motor that uses brushes. When it stops working it is usually because the brushes are either worn out or just plain dirty.

    I have brought some brush motors back to life by spraying Contact Cleaner at the commutator and brushes. (These were not Hard Drivin' motors.)

    I have taken other brush motors apart (also not Hard Drivin' motors), carefully cleaned the brushes and the commutator, and put everything back. Warning, the brushes in a motor are usually spring-loaded.

    I don't know how easily this particular motor comes apart.

    There isn't much else to go wrong with a DC motor.

    If the brushes are worn out you should be able to buy new ones. I have never had to, so I don't know how that works.

    You may be able to find someone in your area who rebuilds electric motors.(Or maybe I'm just dating myself.)

    If I had to buy a new Motor, I would figure out exactly who made it and what size it is, and look for it online at places like McMaster-Carr. The last time I tried they were still there.

    Sorry, I don't have any extra Motors, just the one in my own game. (Actually, I need a seat for my game. One day the old one shattered.)

5. If the Motor is ok, the next thing to look at is the Motor Amp.

    The Motor Amp can be tested without the Motor by connecting a small 120VAC light bulb to the output (25 Watt - 40 Watt) and by jumpering the Thermal Protector.  I suggest making your own cable to plug into J2 on the Motor Amp Board. (The wiring diagram in the manual shows it as P222.)  Pins 1 and 4 normally go to the Thermal Protector in the Motor. (The Thermal Protector opens up if the Motor overheats.) Therefore, P2 Pins 1 and 4 must be jumpered for the Light Bulb tester.

    If all you are going to do is plug in the Light Bulb Tester and look for it to light up during the Send Force Tests, then that's fine.

    If you are going to troubleshoot the Motor Amp, You Need An Isolation Transformer.

    If you don't have an isolation transformer, you can make your own by connecting two 24VAC 3Amp transformers back-to-back. This only works if you are using a light bulb as a load. The Motor draws too much current for this kludge.


    At this point you are on your own. Sorry. (I didn't design the Motor circuit. I just gave Rick the interface he asked for, and I also wrote the test software for it.)

Motor Amp PCB (802 KB PDF)


[Information on jumpering the Motor Thermal Protector, the ribbon cable orientation, and the Motor Amp Board jumpers provided by Tony Rossi. Thank you, Tony.]

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Copyright 2002 Jed Margolin