----------------------------------------------------------------- | "COLORIZING" ASTEROIDS DELUXE | ----------------------------------------------------------------- COPYRIGHT February 1, 1999 REVISION NUMBER: 1.2 REVISION DATE: 31 OCTOBER 2001 CREATED BY: Andy Warren (andywarren@mindspring.com) EDITED BY: Tom McClintock STANDARD DISCLAIMER: -------------------- REMEMBER, NO WARRANTIES, EXPRESS OR IMPLIED, ARE GIVEN. USE THIS INFORMATION AT YOUR OWN RISK. I AM NOT RESPONSIBLE FOR ANY DAMAGES THAT MAY OCCUR TO YOUR PERSON OR PROPERTY. --------------------------------------------------------------------- GENERAL OVERVIEW: ----------------- This enhancement allows you to play a colorized version of Asteroids Deluxe on a color vector monitor. The asteroids will be aqua - a bluegreen that looks like monochrome. The ship and saucer will be magenta (red & blue). Cannon fire will be HIGH white. The shield will change colors as it gets weaker. When the ship breaks up the pieces change colors as they tumble thru space and fade. THEORY OF OPERATION: -------------------- This modification came about when I had an Asteroids Deluxe machine that had the flyback go bad in the b&w monitor. I had enough parts to build two spare color monitors and didn't want to have to buy the part to fix the b&w monitor. So I built a color monitor to replace it. I didn't think the Q2 - 2N3904 transistor could drive all 3 color inputs to the monitor, so I started to add three more in addition to the monochrome output. I was looking at the output section where SCALE0 thru SCALE3 set the brightness of the beam. These were active high TTL signals. Even though the 4 scale lines allow for 16 levels of brightness I didn't think the game used more than 6 or 7 levels. I knew that no objects were drawn with all of the lines off or with just SCALE0 on because it would be too faint for the brightness control. This would be level 1 and 2 of 16. I devised a simple circuit to use the SCALE1, SCALE2, and SCALE3 to switch the monochrome output to the three color guns in the monitor. The 7407 open collector buffer serves to pull down the pull up resistor on the base of each color output transistor leaving it turned off when ever it's SCALE line is low. When the SCALE line goes high the output of the buffer releases the base of the transistor and the pull-up resistor turns it on. When it is on the ZOUT (intensity) signal appears at the emitter of the transistor. Granted that lone Q2 is still providing the drive to the three color guns, the only time it would drive all three is when all of the three SCALE lines were high. This would only be when the beam was "HIGH WHITE" during cannon fire. I figured that if Q2 would have drive problems the cannon fire wouldn't be too bright. The cannon fire was plenty bright! See schematic that follows. INGREDIENTS: ------------ 1 - Asteroids Deluxe board (working) 1 - Color X-Y display: Ampliphone, WG, or EH (working) 1 - 7407 (or 7417) OC buffer 3 - 1/4 watt 2.2k ohm resistors (red-red-red) 3 - 1/4 watt 100 ohm resistors (brown-black-brown) 3 - 2N3904 NPN Transistor 1 - 16-pin machined socket [**optional**] jumper wire soldering iron INSTRUCTIONS: ------------- We must first locate the 74LS175 at board location M6. We are going to "piggyback" the 7407 on top of it, but unfortuantely, neither chip has the same number of pins. So, we must bend the legs on the 7407 to connect it to the appropriate leads of the 74LS175. At this point, you can desolder the 74LS175 from the PCB and solder in a new machined-pin socket so your color modification can be removed at a later date without harming the board. The 7404 must be connected to the 74LS175 in the following manner: 7407 74LS175 ------ ------- pin 01 to pin 01 (pins are connected for support only) pin 03 to pin 04 pin 05 to pin 05 pin 07 to pin 08 pin 09 to pin 10 (pins are connected for support only) pin 11 to pin 12 pin 14 to pin 16 (16) (15) (14) (13) (12) (11) (10) (09) ============================================================ | \ / / | | (14) (13) (12) (11) (10) (09) (08) | | ==================================================== | | | | | | | | | ) ) 7407 | |<---74LS175 | | | | | | | | | ==================================================== | | (01) (02) (03) (04) (05) (06) (07) | | / \ / \ | ============================================================ (01) (02) (03) (04) (05) (06) (07) (08) Next we will add three 2.2k pullup resistors on top of the 7407. The first from pin 14 to pin 10, the second from pin 14 to pin 6, and the third from pin 14 to pin 4. Bend the legs straight out for better connection. View from top: | (14) (13) (12) (11) (10) (09) (08) ==================================================== | |--------------------(|O|O|O)---I | | I-----------------------------(|O|O|O)-I | ) I-------------(|O|O|O)-I | | <---7407 | | | | | | | | ==================================================== (01) (02) (03) (04) (05) (06) (07) | | We now connect the three 2N3904 transistor center legs (base) to the same pins we connected the resistors to. I'm showing the transistors standing up looking at the flat side but they actually lay on top of the 7407. Run a wire from "Z-out" at L/M 11 to the collector of all 3 transistors. The left legs (emitters) of the 3 transistors are now the 'color' outputs for your Asteroids Deluxe board. One solution for getting these output signals to the monitor is to run wires to unused pins on the PCB edge connector (assuming you are using the original Asteroids Deluxe wiring harness). Remember there is no "G" it is :a,b,c,d,e,f,h. |~~~~~| |~~~~~| |~~~~~| | GRN | | BLU | | RED | |_____| |_____| |_____| | | | | | | | | | | | | | | | | | | | | L/M 11 | | L/M 11 | | L/M 11 | | Zout | | Zout | | Zout GRN out| | BLU out| | RED out| | P20 | P20 | P20 | pin 3 | pin H | pin C | | | | 7407 7407 7407 pin 4 pin 10 pin 6 The last step is to put a 100 ohm pull down resistor from each transistor output to ground. A handy place for this is just where the wire is soldered to the unused pins at P20. There are ground points nearby on both sides. From P20, connect these outputs to the color vector monitor you are using. Don't forget to use twisted pairs of wires with one side grounded in order to connect the RGB outputs to the monitor. The R-G-B signals coming off of a 'real' color board such as Tempest or Black Widow will each have a ground wire twisted around them to reduce RFI. When you have checked everything out, pot the mod with a big blob of dielectric silicone (i.e., non-conductive) to keep it safe and secure. Notice how the original "Z-out" is still intact in it's original location, so you can slide the PCB back into a B&W machine if you want. OTHER HELPFUL ASTEROIDS DELUXE INFORMATION: ---------------------------------------------- ASTEROIDS DELUXE PINOUTS P20 _______ GND | 1| A| GND +5V | 2| B| +5V | 3| C| Counter Center | 4| D| Counter Left Audio 1 | 5| E| Audio 2 Start 2 LED | 6| F| Counter Right Player 2 | 7| H| Start 1 LED | 8| J| Player 1 Slam | 9| K| Diagnostic Step Hyperspace |10| L| Self Test Z GND |11| M| Z Out Start 1 |12| N| Coin Center Start 2 |13| P| Coin Left Thrust |14| R| Coin Right Rotate Left |15| S| Rotate Right |16| T| Fire X Out |17| U| X GND Y Out |18| V| Y GND Invert X |19| W| Reset 36 VAC |20| X| 36 VAC + Sense (+5V) |21| Y| +5V - Sense (GND) |22| Z| GND ------- ----------------------------------------------------------------- | END | -----------------------------------------------------------------