Here's a collection of assorted repair information I've collected throughout the years.
Width: 25.25 inches (64.1 cm)
Depth: 36 inches (91.5 cm)
Height: 68.5 inches (174 cm)
Weight: 350 lbs (158.8 kg)
The plywood panels are covered with a black satin vinyl wrap material.
Edge Card Connector
Another problem that all Atari games have is the edge connectors going to the board burn up. You game may already have wires soldered to the board and spliced into the harness. No doubt anybody who owns/worked on several Atari games has seen this. But because I, Robot has a different power supply, it reacts to this problem differently.
The power supply supplys voltage to the game boards, and "reads" a voltage back from the boards (Sense lines) so it can adjust itself to be as close to 5 volts on the board as it can get. The edge connectors get burned over time, and when they start to get bad, the power supply cannot read the voltage accurately, it thinks the boards have a lesser voltage, and supplies more voltage. Eventually, the connectors get worse and the voltage keeps going up until it hits about 6 volts. At 6 volts your boards will start to smell like burned electronics (you know that smell :) and after a while the game will turn itself off because of an over-voltage protection circuit.
This isn't really a puzzling problem, but on I, Robot it can be because everything in the game is wired through the power supply, and when the game shuts itself down, it turns off everything but the fan and marquee light! And the game will always work perfect from when you turn it on until the protection curcuit turns the game off. To fix this, either replace the edge-card connector(s), or splice in wires that bypass the connectors and go directly to the boards. Splicing in wires is easier and faster, but do it the right way! many people (or ALL operators) solder the wires from the harness right onto the board. Dont do it that way, you wont be able to easily remove the boards now. Extend the leads from the burned connectors (only the pins on the extreme 2 rows burn up as they carry all the power to the boards) and attach them to the +5 and GND test points on the board, and use quick-disconnect terminals so you can pull the board out quickly.
The monitor uses smoked glass that is ³/₁₆" thick.
People have reported that when ordering the color you typically you ask for "2nd darkest" glass, or "grey smoke" is also good.
Hall Effect Joystick
I, Robot was the first Atari game to use a hall-effect joystick. The hall-effect stick is a direct replacement for an analog stick, it has the same output. I, Robot's schematics call for an analog stick, which suggest the hall stick was a late addition to I, Robot. The hall-effect joystick was supposed to be a more reliable replacement for the analog joystick found on Red Baron and Food Fight. It wasn't.
The original hall-effect sticks used on I, Robot were very poorly designed, and I don't think there are any I, Robot's out there that didn't have problems with the joystick. Atari later revised the design for use on Road Runner and Escape from the Planet of the Robot Monsters. The updated hall-effect stick is much more reliable than the original sticks so if you are having trouble keeping your original stick calibrated, I recommend replacing with newer rev parts.
Joystick Assembly Drawing
The official Atari part number for the joystick assembly is A040935-01. Here's a copy of the assembly drawing for reference.
Hall Effect PCB Variants
Atari produced three main variants of the Hall Effect PCB circuit. I believe they are all interchangeable (YMMV). The following images show the differences between the 3 versions.
Hall Effect PCB version 1 (A041280-01)
Hall Effect PCB version 2 (A043489-01)
Hall Effect PCB version 3 (A046516-01)
Escape from the Planet of the Robot Monsters
The big problem with the original hall-effect PCB is that the hall-effect sensors bend back away from the magnets after a while and the response gradually gets worse and worse. The only way to correct this it to open up the panel and bend the sensors until you get the proper output.
The PCBs on the later sticks have additional screws that hold the hall sensors against the magnets so they cannot be bent back. A couple of potentiometers were also added so the sensitivity can be adjusted without having to physically move the hall sensors.
Calibrating Your Joystick
Adjusting sticks with original A041280-01 PCBs isn't too hard, there are 2 hall sensors, one for the x-axis and one for the y-axis. Just move the sensors until they are parallel with the magnet. It should not be touching the magnet, but a tiny bit away from it. On the old sticks, the only way to know if the sensor is the right distance from the magnet is to put the game into joystick test and see how it works.
Adjusting sticks with later rev PCBs is much easier, just align the hall sensor parallel to the magnet, and then move the screw so it just touches the back of the sensor (NO pressure). The screw is there so the sensor wont bend back and become less sensitive. Enter test mode and adjust the pots with a small screwdriver until everything lines up.
Spinning Joystick Handle
The original joystick handle could spin in place, which was changed in later versions. The length of the ⅛" pivot ball roll pin determines if the joystick rotates or is held in place. The longer roll pin sits between grooves on the lower housing, preventing the handle from spinning. You can modify any version of stick to change the behavior.
Roll pin length of ⅞" allows joystick to spin relative to housing
Roll pin length of 1 ½" prevents joystick from spinning relative to housing
The following image highlights the location of the roll pin that needs to be replaced.
Refurbishing Your Joystick
The Atari logo joysticks wear out over time, and older sticks tend to feel loose or sloppy. Your joystick can be refurbished by replacing the following wear items:
These parts are available online, but are starting to become scarce. I personally recommend Mylstar at ArcadeFixIt who has been selling NOS Atari parts for many years. eBay is another resource, however be aware that many joysticks on eBay are well worn.
When replacing the parts, make sure you lubricate them generously. NyoGel silicon grease has been used for many decades, however I prefer using white lithium grease.
The following diagram highlights the wear parts that should be replaced when servicing a worn joystick.
Atari Joystick Assembly Part Numbers
These are the Atari part numbers for the various hall-effect joystick assemblies, as taken from the official Atari documents. Note that many parts are in common with regular Atari 4-way and 8-way joysticks, and parts from those sticks can be used to repair/refurbish hall-effect sticks.
Shares the same top level assembly part number as I, Robot but uses a different hall effect PCB
Escape From The Planet Of The Robot Monsters
Upper assembly has a round restrictor plate, otherwise the same as prior versions
Lower assembly has a different Actuator and PCB
This section captures information on some of the integrated circuits used on I, Robot.
2114-2 Alphanumerics RAM
Holds the 32x32 character buffer for the Alphanumerics screen overlay
Spec: 1k x 4-bit RAM, 18 pin DIP
Atari part number 90-7036.
Datasheet can be found here.
Self test error: BAD RAM AL xxx
2 chips on Video PCB location 2M 2N (note that manual self test procedure incorrectly says chips are on CPU PCB)
2901-C Bit Slice Processor
These are 4-bit ALUs at the heart of the mathbox co-processor. I, Robot uses 4 of them.
Atari part number 137340-001.
Datasheet can be found here.
The parts are on the CPU board, locations 4/5K, 4/5L, 4/5M, 4/5N
Used for the video frame buffer.
Spec: 64k x 1-bit DRAM, 150ns or better, 16 pin DIP
Atari part number 137339-150.
Datasheet can be found here.
14 total parts, locations on video PCB: 11F, 11H, 11J, 11K, 11L, 11M, 11N, 12F, 12H, 12J, 12K, 12L, 12M, 12N
Possible cross parts:
41256 (Tim Lindquist)
Apparently the batch of 6116 RAM chips Atari used in I, Robot had flaws. Pretty much every board will have problems. You will know when the chips start to go bad when you see gibberish on the screen. If you hit the fire buttons quickly in attract mode, the game will scroll through the screens fast, and sometimes you will see graphics from the previous screen mixed in with the graphics in the current screen. It will last only a second, but it is the RAM chips that do this. Usually the machine will not do this until it has been sitting on for a while and is all nice and warm.
Since there are known problems with 6116 chips, you probably should replace all of them. There are 8 total on CPU board, and 4 total on the video board. Get parts rated at 120ns or better.
Spec: 16k SRAM, 2048 x 8-bit, 120ns, 24 pin DIP
Atari part number 137211-120
Datasheet can be found here.
The chips are used in the following circuits:
Main working RAM
Self test error: BAD RAM W0 xxx
Self test error: BAD RAM W1 xxx
Self test error: BAD RAM W2 xxx
4 chips on CPU PCB, locations 2A, 2B, 3A, 3B
Self test error: BAD RAM MA xxx
4 chips, on CPU PCB, locations 1N, 1P, 2N, 2P
Video processor RAM
Self test error: BAD RAM C0 xxx
Self test error: BAD RAM C1 xxx
4 chips on Video PCB, locations 1C, 1D, 2C, 2D
ICY Video Processor
Atari part nuber 137410-101.
This is the custom ASIC at the heart of the rasterization engine. It's responsible for drawing the dots, vectors, and polygons to the frame buffer. Without this chip you won't have any game graphics :(
I've been hearing on forums that people with long working I, Robots are starting to have ICY problems after the machine gets warm. If your game is working after 40+ years, well you're likely on borrowed time.
If you're trying to replace this chip, well... that's a problem. They're entirely custom, and Atari only produced a limited run of these chips back in 1984. The word is that the run had problems, and a good percentage of those parts didn't work. The few replacement chips Atari stocked are long gone and/or in the hands of collectors.
If you need an ICY, your best bet at this point in time is to scour arcade collection/restoration forums on the internet hoping to find one coming up for sale. Or check eBay and other auctions looking for dead boards to cannibalize.
There is hope however. Early PCBs exist in the field which have the discrete IC equivalent of the ICY chip. These boards are labeled "ICE WORLD VIDEO BOARD". Ideally someone will document this circuit, and make a suitable daughter board replacement to duplicate this functionality. If you have any information which might help with a project like this, please reach out to me!
Thes hold mathbox object data. These failed early on every I, Robot. When they fail, your machine will continue to report the error "You've hit a black hole".
There are 4 parts with custom programming. It is recommended you replace all 4 parts at the same time.
When replacing these parts, you will need to program the parts with the appropriate Atari ROM file.
The 23128-2 ROM is actually a masked ROM. So you will need to replace with a regular programmable ROM 27128-2
Atari spec: EPROM, 128K_(16Kx8), 200ns
For 2764-2 you want 200ns parts or better
Atari spec: EPROM, 8Kx8, 200ns
Atari part number 137324-1221.
This is an Atari custom audio chip. It's essentially 4 separate POKEY chips (Atari part number CO12294) on one board. Official Atari documentation on the POKEY chip can be found here.
These quad chips are very hard to come by, but not to worry as discrete POKEY chips are easily available as they were widely used in the Atari 2600 and Atari 8-bit computers.
Strangely, apparently Atari created a "QUAD POKEY ELIMINATOR" PCB (Atari part number A042622) for Major Havoc which utilizes 4 individual POKEY chips and acts as a drop-in replacement for the Quad-Pokey. I guess Atari themselves had problems getting/making Quad-POKEYs in volume. In any case, both POKEYs and reproduction QUAD POKEY ELIMINATOR PCBs are still pretty easy to find online.
Hobbyists have also created Quad-POKEY replacement daughterboards that emulate the behavior of the original chip.
This is an NVRAM used to save high scores and accounting info.
Spec: 256 x 4-bit non-volatile RAM, 18 pin DIP
Atari part number 137288-001.
Datasheet can be found here.
Atari used the XICOR X2212D
Location: CPU PCB 4B
This section was copied from Chapter 2 in the I, Robot Operators Manual.
The game will test itself and provide data to show that the game circuitry and controls are operating properly. Self-test data is presented visually on the video display and audibly through the speakers. No additional equipment is required.
We suggest you perform a self-test when you first set up, each time you collect money, change the game options, or suspect game failure.
Ten self-test displays provide a visual check of the following:
Game accounting and option-switch information.
Read-only memory (ROM) and random-access memory (RAM) circuit operation.
Joystick and switch operation.
Sound-generator circuit operation.
Mathbox circuit operation.
The dot-, vector- and polygon-generator circuit operation.
Character-generator circuit operation.
When the self-test switch (located on the utility panel behind the coin door) is turned on, the game enters the Self-Test mode. The following self-test displays are arranged in sequence in which they occur after the self-test switch is turned on. After Screen 10 - Size and Centering, the sequence starts over with Screen 2 - Hardware and Switch Test. Turn the self-test switch off then on again to obtain Screen 1 - Accounting and Options.
Screen 1 - Accounting and Options
The Accounting and Options screen, as shown in Figure 2-1, displays the accounting information and the option settings. The totals in the Accounting section of Screen 1 are those accumulated since the game was first turned on or last reset.
Figure 2-1 Accounting and Options
The following information is displayed in the Accounting section of Screen 1:
AUX COINS shows the number of free coins selected by the auxiliary coin switch in the normal play mode.
PAID COINS shows the total number of coins inserted into both game coin mechanisms
GAMES PLAYED shows the total number of free and paid games played. The number of Doodle City games played appears as D: XXXX on the same line. Add the Doodle-City number to the number on the left to obtain the total games played
AVG GAME TIME shows the average time, in minutes and seconds, of all the games played.
TOTAL GAME TIME shows the total time, in hours, minutes, and seconds, of all the games played.
TOTAL TIME ON shows the total time, in hours, minutes, and seconds, the game has been on.
Resetting the Accounting Information. The accounting information can be reset by simultaneously holding the FIRE button down and pushing the joystick forward.
Resetting the High Scores. We suggest that you reset the high-score table after any changes are made to the operations that may affect the average time time. The high-score table displayed in the Attract Mode can be reset by simultaneously pressing the FIRE and Start 2 buttons.
Changing the Options. The Options section of Screen 1 shows the current option-switch settings. The options can be changed by resetting the option switches located on the central-processing unit (CPU) printed-circuit board (PCB). Refer to Chapter 1 for option-switch information.
Doodle-City Time Limit. The time limit for Doodle-City can be set to between 1 ½ and 10 minutes by simultaneously pressing the START 1 button while moving the joystick.
Simultaneosly press the Start 1 and 2 buttons to obtain Screen 2.
Screen 2 - Hardware and Switch Test
Screen 2 is divided into two sections: Hardware Test and Switch test. The Hardware Test section is divided into two segments that show the condition of the ROM and RAM circuits. If the hardware test passes, the message ROM OK will appear in the top segment and RAM OK will appear in the bottom segment as shown in Figure 2-2.
Figure 2-2 Hardware Test - Passes
Figure 2-3 Hardware Test - Fails
If the ROM test fails, the top segment of the Hardware Test section will give the location of the ROM circuit that failed; the bottom segment will be blank as shown in Figure 2-3. If the RAM test fails, the bottom segment will show the following error messages:
The Switch Test section of Screen 2 shows the condition of the joystick, dual-inline package (DIP) option, coin, start, and FIRE switches. The X- and Y-hexadecimal numbers show the horizontal and vertical range of the joystick control. The joystick is electrically centered and checked for the proper horizontal and vertical range in Screen 4 - Joystic Test 2.
The DIP option-switch settings at location 5E on the CPU PCB are shown by the top group of eight digits on the right side of the screen. The bottom group of eight digits show the settings of the option switches at location 3J on the CPU PCB. The digits begin with switch 1 on the left and are numbered sequentially to switch 8 on the right (a 0 indicates that the switch is off, a 1 indicates that the switch is on).
The coin, start, and FIRE switch readouts change color as each switch is pressed to indicate proper operation.
Press the Start 1 button to obtain Screen 3.
Screen 3 - Joystick Test 1
The Joystick Test 1 screen, as shown in Figure 2-4, displays the condition of the joystick. X- and Y- axis decimal readings of the joystick appear in the upper right hand corner.
Press the FIRE button to start the test. The messages WAIT WHILE TEST OCCURS and DO NOT TOUCH JOYSTICK will appear. The test is completed after 10 seconds. If the test passes, the message GOOD STABILITY will appear and the display will automatically proceed to Screen 4 - Joystick Test 2.
If the test fails, the message BAD STABILITY will appear to indicate an unstable joystick circuit. If desired, press the Start 2 button to obtain Screen 4.
Figure 2-4 Joystick Test 1
Screen 4 - Joystick Test 2
The Joystick Test 2 screen, as shown in Figure 2-5, is used to electrically center the joystick and verify that the control range is within acceptable limits. The minimum and maximum X- and Y-axis readings are shown. The message BAD VERTICAL/HORIZONTAL CENTER indicates a faulty joystick or associated circuitry. Repair the fault before proceeding with this test.
Move the joystick around its extreme outside mechanical limits and check that the flashing box draws a continuous dotted frame around the outside of the yellow box. Move the joystick and completely fill in the area inside the dotted frame with dots. Check that the dot pattern is continuous and uniform without gaps.
Prese the FIRE button to go back to Screen 3 - Joystick Test 1, or press the Start 1` button to obtain Screen 5.
Figure 2-5 Joystick Test 2
Screen 5 - Sound Test
The Sound Test screen, as shown in Figure 2-6, is used to verify that the sound microprocessor and associated circuitry is operating properly. Use the joystick to select the sounds (not all are used during game play). Press the FIRE button to start the sound.
Presse the Start 1 button to obtain Screen 6.
Figure 2-6 Sound Test
Screen 6 - Alphanumerics
The Alphanumerics screen, as shown in Figure 2-7, is used to verify that the alphanumeric character-generator circuits are operating properly.
Press the Start 1 button to obtain Screen 7.
Figure 2-7 Alphanumerics
Screen 7 - Dot, Vector, and Polygon Test
The Dot, Vector, and Polygon Test screen, as shown in Figure 2-8, is used to verify that the dot-, vector-, and polygon-generator circuits are operating properly. Press the FIRE button to select a dot, vector, or polygon display.
To aid in troubleshooting the video processor, the video processor can be pulsed to provide an oscilloscope sync signal. Press the Start 2 button to pulse the video processor. Connect the oscilloscope sync input to pin 12 on the integrated circuit at location 4R on the Video PCB. Press the FIRE button to stop the pulse mode.
Press the Start 1 button to obtain Screen 8.
Figure 2-8 Dot, Vector, and Polygon Test
Screen 8 - Color Bars
The Color Bars screen, as shown in Figure 2-9, is used to verify that the video circuits are operating properly and the display is adjusted for the appropriate colors. The display should contain eight distinct horizontal rows of color bars with eight different shade segments in each color bar. Examine the Color Bars display for the following characteristics:
The eight color bars (from top to bottom) should be white, red, orange, yellow, green, cyan, blue, and purple. Each color bar should contain eight separate segments of progressively lighter shades of the same color.
All of the color bars should have the same relative intensity.
If the preceding display characteristics are not correct, refer to the Display Manual for the appropriate adjustment procedure or to determine the possible cause of failure.
Press the Start 1 button to obtain Screen 9.
Figure 2-9 Color Bars
Screen 9 - Grid Pattern
The Grid Pattern screen, as shown in Figure 2-10, is used to verify that the display linearity and convergence are properly adjusted. Examine the grid pattern for the following characteristics:
Grid lines should exhibit no pincushioning or barreling and the lines should be straight within ⅛ inch.
Convergence should not exceed 2.0 mm.
If the display characteristics are not within limits, refer to the Display Manual for the linearity and convergence adjustment procedures or to determine the possible cause of failure.
Press the Start 1 button to obtain Screen 10.
Figure 2-10 Grid Pattern
Screen 10 - Size and Centering
The Size and Centering screen, as shown in Figure 2-11, is used to verify that the screen size and centering is within acceptable limits. The displayed frame should be within ¾ inch from the edges of the screen on all four sides. If not, refer to the Display Manual for the size and centering adjustment procedures.
Figure 2-11 Size and Centering
Document I found online showing how the harness should be installed in the cabinet