Document Title: [QBert Tech.html (html file)]
MLB = Main Logic Board SB = Sound Board -- = No Connection Main Logic Board (MA-378) 60-contact edge connector (A1P1) A +5 VDC 1 GND B +5 VDC 2 GND C +5 VDC 3 GND (COIN RETURN) D -- 4 -- E COIN 1 (OPTIONAL) 5 COIN LOCKOUT (OPTIONAL) F COIN METER 6 KNOCKER* H -- 7 -- J -- 8 -- K -- 9 -- L -- 10 -- M A6P1-2 (SB) 11 -- N -- 12 A6P1-4 (SB) P -- 13 -- R SELECT TEST SW** 14 GND S COIN SW #2 15 STEP TEST SW*** T COIN SW #1 16 1P START U -- 17 2P START V -- 18 UP-LEFT W -- 19 DOWN-RIGHT X -- 20 DOWN-LEFT Y UP-RIGHT 21 -- Z A6P1-8 (SB) 22 A6P1-9 (SB) a A6P1-11 (SB) 23 A6P1-12 (SB) b VERT. SYNC 24 RED c -- 25 BLUE d VIDEO GND 26 GREEN e HORIZ. SYNC 27 +11.5 VDC f +5 VDC 28 GND h +5 VDC 29 GND j +5 VDC 30 GND *connects to one end of the knocker solenoid, which is wired in parallel with a 1N4004 diode. The other end of the solenoid connects to +30 VDC, which also provides power to the audio amp. **closed = game; open = test. ***normally open. Sound/Speech Assembly (MA-216) 24-contact edge connector (A6P1), only one side of board has contacts. A -- 1 +12 VDC REG. B -- 2 A1P1-M (MLB) C -- 3 -12 VDC D -- 4 A1P1-12 (MLB) E -- 5 +5 VDC F -- 6 GND H -- 7 AUDIO OUTPUT J -- 8 A1P1-Z (MLB) K -- 9 A1P1-22 (MLB) L -- 10 +30 VDC REG. M -- 11 A1P1-a (MLB) N -- 12 A1P1-23 (MLB)n.
Switch 1 Demo Mode * On infinite lives Off normal play Switch 2 Attract Play On no sound Off sound Switch 3 Normal/Free On free play Off normal play Switch 4 Game Mode On cocktail Off upright Switch 5 Not Used Switch 6 Kicker On kicker on Off kicker off Switch 7 Not Used Switch 8 Not Used *In demonstration mode, the player will have infinite lives and can progress through the rounds by hitting either start button.
I finally got Q*bert JAMMAtized and I thought I'd pass along how I got the job done.
For a bit of background I build various adapters to allow older board sets to match up to the JAMMA wiring scheme. It goes like this: Louis's Harness shop (1-800-365-1941) sells a little chunk of circuit board that allows you to mate 2 female 56 pin (JAMMA style) connectors together. The female connectors are available lots of places.
You plug the male piece of circuit board into the JAMMA connector in the game. Then plug the other 56 pin connector to the circuit board. Put whatever connectors you need on the boards you want to use. Connect wires as needed between the connectors on the game boards and the solder terminals of the 56 pin connector.
Once you have done a few it becomes fairly simple and some adapters are useful for many games.
Q*bert (GV103) requires a large Main Logic Board and a Sound Board about a quarter of the size of the Main Logic Board. I have original docs but found David Shuman's pinout info on wiretap very helpful and included a copy at the end of this.
On to the adapter. I'm not going to explain this in detail. I know many of you are programmers with minimal electronics skills but to walk those people through this connection by connection is more than I want to take on. What I'm providing here is pretty basic stuff and if you can't handle the electronics get someone to help you that can.
My goal was to make Q*bert plug into a JAMMA harness with as few modifications as possible. The first issue was that Q*bert puts out separate active high H and V syncs and JAMMA wants an active low composite sync. I experimented with several circuits but the one that seemed to work the best for the monitor that I was using was to first invert each sync (with a 74LS04) and then AND the separate syncs (with a 74LS08). Again, this is what worked best for the monitor I was using. Sometimes it's easier to abandon trying to combine the syncs and just connect the separate syncs directly.
The next issue was the +30 VDC required by the audio amp on the sound board. After looking over the schematics I determined that the only thing that uses the +30 is the final audio amp, U23, an LM379S. My solution to the fact that the LM379S needed +30 (not provided by JAMMA) was to simply not use the LM379S amp.
The following is a drawing of the 2 watt audio amp circuit I've used successfully for some time. B. G. Micro has the LM380s cheap. Franklin Bowen was nice enough to do the ascii art.
C2 +12v | | | |------| |----- GND | | | | | C5 | C1 | +| |- |------| |-----GND +| |- | | | Input---| |------+ | | | | |\ | > 2 | \ | C3 VR1 < <-------+ \ | 14 > | LM \ +| |- 4-16ohm spkr < | 380N \ ____________| |------- | | / 8 out | | | | | / | | | / | 7,3 > | | / | < | |/ | > R1 | | < | | | +----------------+ C4 --- | --- | | | | +-----------+ | GND C1= 50 uF 12v C2= .1 uF 12v C3= 250 uF 12v C4= .1 uF 12v C5= 20 uF 12v R1= 2.7 ohm VR1= 10k ohmNone of the values in this circuit are critical. Feel free to use up some misc.
To use this with the Q*bert adapter don't connect anything to the +30 VDC or the sound board audio output (pin 7). Instead wire up the amp just described with the output directly connected to the speaker. For the input of the separate amp, solder a wire on to the bottom of the sound board at pin 9 of U23 (the on board amp's input). Now, the external amp does all the work.
The other non-JAMMA power supply voltage required by Q*bert is -12 VDC. I suspect that you could get away with powering the -12 with the JAMMA -5 but didn't try it myself. Enough of the older games required -12 to make me supply that voltage with a separate supply and connector.
The last complication was caused by the fact that the joystick for Q*bert is rotated 45 degrees from the way a standard joystick is mounted. It is a standard 4-way stick, it's just turned 45 degrees. This is why the pinout info contains connections for things like "DOWN-RIGHT" on a single pin.
I didn't want to remount a stick so I took advantage of a suggestion by Mark Jenison (I mentioned your name Mark, are you happy now? :-) ) and used 4 "OR" gates on a single 74LS32 to make an 8-way standard joystick do the job without rotating its mounting. The wiring went like this:
Joystick Q*bert input up ----1 \ ---- 3--- up-left left ---2 / up -----4 \ ---- 6--- up-right right --5 / down --10 \ ---- 8--- down-left left -- 9 / down --12 \ ---- 11-- down-right right -13 /I also added 4.7K (again, a non-critical value) pull-up resistors between each joystick connection and +5. Normally the game board provides the pull-up resistor but here its needed at the joystick to pull the inputs high. The joystick contact closure brings the inputs low.
With this scheme 2 adjacent inputs going low when the joystick is moved to 45, 135, 225, or 315 degrees gives one low output in the direction required by Q*bert. I suspect the joystick is more difficult to use than if you really rotated a 4-way joystick but the game is definitely playable.
I know some of you will be disappointed but I didn't connect a cabinet knocker but you gotta make some hard decisions at times ;-)
Well, I hope you people found this interesting. Thanks to Mark Jenison who worked with me on the adapter and to Kevin Klopp (alias mowlawnman) for loaning me his working sound board to help me debug mine.
Pinouts for bootleg (single board PCB) Q*Bert (Gottlieb 1982) component side solder side -------------- ----------- GND 1 +5V GND 2 +5V GND 3 +5V +12V 4 +12V (-5V) -12V 5 (-5V) -12V 6 AUDIO OUT 7 8 TEST MODE* 9 SELECT SW 1P START 10 COIN 1 2P START 11 COIN 2 1P UP-LEFT 12 2P DOWN-LEFT 1P DOWN-RIGHT 13 2P UP-RIGHT 1P DOWN-LEFT 14 2P UP-LEFT 2P DOWN-RIGHT 15 1P UP-RIGHT VIDEO RED 16 VIDEO SYNC VIDEO BLUE 17 VIDEO GREEN 18 19 GND 20 +5V GND 21 +5V GND 22 +5V * TEST MODE SWITCH - GAME MODE TO GND., TEST MODE TO OPEN Pinouts obtained from operator panel on my bootleg machine. Your mileage may vary.
From: email@example.com (Joey Oravec) Newsgroups: rec.games.video.arcade.collecting Subject: Re: TECH: Q*Bert no sound Date: 14 Jul 2000 02:27:46 GMT Lines: 53 someotherguy (someotherguy@SPAM_SUCKSmediaone.net) wrote: : Bob Roberts sells LM379's. We fixed a Q*bert here with one. There's : also a hack to the original power supply to prevent blowing up the : chip again, it's in an overvoltage situation by design, explaining the : premature failures...just for grins I attached an extra heatsink to : this one. Ok. I assume you mean roys "swap the zener to +28" posting. Do people always neglect what I write? There is bad engineering in that circuit and going to +28 makes it worse. This does NOT explain the premature failures. I told Roy before and he acknowledged it might be an issue. He's one awesome guy, but I think he missed this important fact on his original posting. Running that regulator at +28 causes MORE current to be shunted to ground. They use the simplest regulator possible: a zener diode biasing a transistor. Correct me if I'm wrong since I've only had my hands on about 5-6 qberts ever. But I noticed the trend that dead sound always had bad power. That IC is rated just about fine for what's being input to it, +30 is just fine for that chip. Don't get me wrong it's not a superb chip but there is a larger problem. The problem is that the regulator resistor and zener basically need to be 5watt. +36vDC is being regulated down to +30vDC. Bringing that zener down to +28 causes yet more current to shunt to ground which is a bad idea. If that zener goes then chances are good the chip could eat +36 (and die) and then the transistor could get shorted (and die). More evidence? most power boards are horribly charred beneath those components because current kills on that regulator. Already that zener at 30v5w runs VERY hot to the touch, running more current at 28v5w only kills it faster! These PSU's were designed to last about 18 months for while the game was popular, and then who cares. They were designed to be functional... That's about it. Not practical to test and prove chip reliability. But hey. I upgraded my regulator and have had zero difficulty among 3 qberts needing Lm379s replacement for 2 years. The others with dead sound were NOT dead amp chips. I think that chip gets a worse rap than it deserves thanks to the ugly regulator in the power supply and its nonavailability today. Correct me if I'm wrong, I'd love somebody find a flaw in my logic and keep my qbert's sound working forever. But I keep seeing this advice pop up and keep giving it the smackdown. Maybe somebody can notice my post next time they feel like advising the +28 modification, or else comment as to why I'm wrong! -- O..O Arcade machine collection: (----) http://www.science.wayne.edu/~joey/arcade/ ( >__< ) IRC - EFNet #rgvac: demigod2k ^^ ~~ ^^
Newsgroups: rec.games.video.arcade.collecting Subject: Re: QBert doesn't power up Date: Fri, 21 Apr 2000 06:40:34 GMT Since you're getting no signs of power, and you are on a known good outlet, the first thing to check is your fuses. Get a multimeter (don't rely on a visual inspection) and check continuity between the blades of the fuse holders. That rules out both the fuse and poor contact at the holder. Fuses are your most probable culprit here. Once you've got that sorted out, and the machine powers up, keep your fingers crossed that your power supply board and sound board are good! These seem to be common failure items on Q*Bert. Then, go to Chumblespuzz's homepage for more Q*Bert info: http://members.home.net/chumblespuzz/ in the arcade section, he has a page for Q*Bert that describes troubleshooting sound problems, and also a preventative fix to keep from zapping the sound. If you find you have a sound problem and need to replace the amp chip, Bob Roberts has them for something like $10. http://personal.msy.bellsouth.net/msy/b/o/bob147/ My friend BVC's Q*Bert was suffering from a bad P/S, sound board, and monitor. With the help of Eric Anderson (rebuilt the P/S), Chumblespuzz (Eric used his info to mod the P/S), and Bob (supplied the amp chip)...and.now that I've replaced the monitor, Q*Bert lives! Richard http://people.atl.mediaone.net/someotherguy