by firstname.lastname@example.org, 05/25/99.
Copyright 1999, all rights reserved.
Table of Contents
Getting Started: Introduction, Schematics, Links:
Atari manufactured these Black & White Vector games during 1979-80, Asteroids and 1980/81, for Asteroids Deluxe.
Also a good Atari Vector site is Game Archive Vector Page.
Star Tech Journal
Getting Started: Required Repair Equipment
Wire wrap and the
tool used to strip it. You can buy
To correct this probem, look at the "via" (plated thru holes) and if the solder is puckered or missing (!), resolder these holes and add some new solder. To ensure complete reliability, stitch a piece of wire-wrap wire thru the holes and solder on both sides of the board.
2. Problem: P1/P2 Blink Flash. No Game Play
When the machine is turned on, the lighted player one/player two buttons blink/flash, and the game continually resets or basically looks like its doing nothing. The spot killer is lit.
a. Fix: Check the power supply, the large capacitor sometimes comes loose, you'll have to remove it from the cabinet to check it from the bottom.
b. Fix: When my board had that problem, it turned out to be loose caps on the board. Specifically, the largish ones on the right upper side. They mostly have to do with the sound FX circuits. But, if they come loose and make/break contact, they send surges that reset the board. The other suggestions I've seen are valid too. Those caps however, since they stick up off the board, may tend to get loose first, but you should probably check all solder joints.
Cause: Connector to logic board not making good contact with the edge fingers.
Fix: I used a pencil eraser to clean the fingers. I also noticed that the pins inside the connector were worn and not making good contact. I used a jewelers screwdriver to gently put a small bend in each pin. (I really should replace all the pins!)
3a. Problem: No video, P1 and P2 stay lit, loud humming noise.
Cause: The 5V supply from the Audio/Reg board was reading about 4.2V
Fix: Replace the LM305 (Q1) regulator, and readjust the voltage.
Cause: No 5V from the Audio/Regulator board.
Fix: Replace the 2N3055 (Q3) transistor.
Initially, the board's self test reported the fifth RAM in the test (at location N4) to be bad, so I replaced it. Then it reported the fourth RAM bad (location R4), so I replaced that. Next, it reported the third RAM (M4) bad, so I replaced it; however, it still reported M4 bad, so I tried another 2114, with the same result. However, with a little toggling of switches and probing around, the RAM failures have inexplicably gone away, and the board now passes its self test.
Fix: look at your sockets and make sure they have the same plating as the IC that plugs in to them. If you have tin-plated leads on an IC plugging into gold plated socket contacts (or vice versa) you will get some REAL interesting intermittents.
Fix: See the text file describing the implemenetation of 2x speedup and un-do it.
Asteroids Deluxe recently started having a little intermittent trouble with the buttons. While rotating and thrusting, pressing fire will interrupt the rotation of the ship, resulting in no rotate or fire.I put in brand new switch contacts but once in a while it will still do it. Sometimes it is very often other times once in a great while. I double checked the wire harness and connectors and they seem to be fine. ( .03 ohms from the switch contacts to the main board and self test seems ok, all switches respond ) Has anyone ever run into this problem? Should I be looking at the inputs to the J10 and L10 data/sel/multiplexer, or the IC's ? Intermittent fault makes me think wiring, or switches, or main board connector, or wire traces on main board.
Fix: It's been three
years since I had a similar problem, so my memory may be
All sounds are there but the ship fire sound is a high pitched "tink" sound. The sound circuit looks pretty simple for it and I've changed most of the components there with no luck.
Fix: Check the capacitors that stick up all over the board, especially the upper right corner area. There are quite a few that are for the various sounds, and since they stick up they tend to work loose.
Suddenly several of the game's sound effects have vanished. Specifically, the ship shot, saucer shot, and saucer flying effects have degraded into various quiet clicks, pops, and buzzes, though they activate at the proper moments and for the proper duration's. From looking at the schematics it seems strange to me that these would all fail simultaneously, while leaving the thump, explosion, and new life sounds intact.
Fix: 12V regulator had failed, and was only putting out around 4 volts. This was the cause of the problems, and was easy to fix.
Missing do,do...do,do sound:
Fix: turned out to be one of those big caps near the upper right corner of the board had one lead broken. Pretty simple when you know where to look.
Fix: Discovered that someone had cut the "Disable Audio" trace on the supply/audio board which disabled the audio amps.
Fix 1:OK you're saying. Bad 26,000 uF cap in power supply (chassis) which supplies +10.8 volts unregulated to the amps. Typical problem. Replaced it with a good 30,000 uF cap, hummmmmm....
Fix 2: involves both replacing the power supply with a switcher and put a better amp in (what's in there, a wimpy LM386 or something, yes ?).
Fix 3:After trouble-shooting every possible avenue. ( power supply
/ audio board,
Asteroids resets itself every couple of hours. Also, the brightness of the screen varies constantly. It almost flickers brighter and dimmer. I've found that If I tap the pcb (in no particular place) the picture gets bright and steady instantly, but then proceeds to get dimmer and dimmer.
Fix: It was related to the edge connector. Resoldered the tabs on the pcb where the edge connector mates with the pcb. This improved contact between the board and the connector, and the problem went away.
Fix: In soldering, the pads can lift and be ruined. Why not clean the edge connector and if the pins in the connector are removable pull them/clean/reopen/replace or just plain replace pin and if they are not removable use a spring hook tool (dentist tool) to pry them back toward the center and spray them with a contact cleaner. BTW: This is the 2nd most common problem in Asteroids/Atari.
Fix: Check the game board to see if you are getting the proper signals. The test points that are labeled "X out" and "Y out" are the places to check for vector generation. If the board isn't supplying from +10V to -10V on the X out or+7.5V to -7.5V on the Y out, the spot killer circuitry will light the LED on the monitor deflection board. If there are deflection voltages coming from the game board, then you will need a more detailed look into the monitor deflection board. It could be as simple as a blown fuse or transistor. Gregg Woodcock's XY FAQ is useful even though it is aimed at color XY monitors.
Cause: Oxidation between ICs and sockets.
Fix: Remove microprocessor
and EPROM's, clean leads with a pencil eraser, reseat in sockets.
The person I bought it from tried a different board in it and the prob went away. Would this be a result of a vector generator IC?
If I put the game in test mode the "chain link fence" looking grid has jagged lines in it where this screen should have nice 45 degree lines in it as to test for this type of prob.
Fix: turned out to be one of the AD651J DACs. I've also had people tell me that a counter could be the problem.
Cause: Y-axis deflection transistors (Q608, Q609) on Electrohome deflection PCB degraded (?).
Fix: Swap Q708 and Q608,
Q609 and Q709 as a test, or just replace Q608 (2N3716) and Q609 (2N3792)
When I put the
game into test mode, the cross-hatch is not quite right.. it looks sort
of like this:
notice that the points where the zig-zags are supposed to meet, they do not...there's an obvious "gap"...The box around the cross-hatch looks fine.. the 0's (zeros) inside the box are fine, too... it's just the cross hatch that's all screwed up - causing the asteroids and ship, etc. to look messed up, as well.. I know all the IC's in the AVG section are good... they're all socketed and the same parts work fine in another board set...
Fix: Try the BIP pots on the game board.
Despite the fact that the self test thinks nothing is wrong, the board's video output is very corrupted. It appears that the X-axis is being properly reproduced, but vertically the vectors are distorted and only seem to appear in five horizontal strips, each about 1 cm tall. This makes the self test crosshatch appear as several strips of saw-toothed lines. The game logic works fine, as a game can be played and heard normally, albeit with corrupted video.
Fix: The problem was in the y axis counter on the logic board. Replace all the ALS191's in the y axis circuitry (I think there are 3). Another tip is to go to Radio Shack and buy a can of freeze spray. While the game is on and someone is watching the screen give each chip in the y axis circuitry area a good blast one at a time. If anything on the screen changes at all, replace the chip. I found my bad chip by holding my finger on each chip on the board (hold it on for about 10 seconds), if any logic chip is warm, replace it.
Fix: Sounds to me like you have a bad D-A converter. But maybe you only have a few missing address lines to the D-A. The least significant 8 lines to the D-A come from a 74LS374 latch at location B10 (-01 thru -04 status board) or B11 (-05 or -06 board). It could also be the 74LS157 multiplexer chip at location B/C10 (-01 thru -04) or B/C11 (-05 & -06).
Fix: Reduce the X output on the main pcb. Tiny pot, labeled X size. Flip the black slide switch into the test mode (located on too of the cash box, or on the right side of the inside wall of the cabinet) this will give you a cross hatch pattern inside a box. Adjust the box so it just touches the edges of the picture tube. The "BIP" adjustments ensure that the lines are correct diagonally...
It NORMALLY does is put up a bunch of cross hairs, which has significantly more white than a game being played. What you will see when you switch it into test mode (with the broken Asteroids board) is a more intense white beam across the bottom of the screen. My Asteroids board has this EXACT problem, and it turned out to be two problems: A Bad TLO 82 on the output stage of the Y drive circuit and a bad DAC. That fixed the problem when I replaced these two parts. The DAC is also hard to measure because it's a current drive instead of a voltage drive DAC.
From: Ben Cole:
Fix: Replacing the M6 (74LS175N Quad D flip flop ) solved the problem. M6 receives the scaling signals from K6 memory data latch. Special thanks to Jess Askey, email@example.com for helping me with that problem.
From( RGVAC posting): firstname.lastname@example.org
Fix: Watch the filement
in the CRT, if it's dimming when the picture fades,
From (vector list):
Fix(suggested not tested):
Have you checked the HV diode between the transformer and the picture tube
? Use Freeze spray on it -- if it works, that's the problem.
The Asteroids PCB is divided up into 2 basic sections.
1)The program section consists of:
To determine which section is causing the lock-up, clip and lift pin
from Bernie Barranger in ST*J.
Unplug the monitor from the harness at it's molex connector to avoid damage to it - when the monitor sits in spot killer state too long things can fry!
1. Start out by verifying
that the clock is running. (The crystal on these boards
2. To figure out
who is causing the watchdog resets (the MPU or the VSM (Vector State Machine)),
take the 74LS42 at L5 (L6 on Asteroids) and socket it,
a) If the board stops
resetting, the MPU is not the problem and youshould be
b) A board that is still
resetting has a problem with the MPU and also possibly
3) Place pin 1 of the 74LS42 (DMAG0) back into it's socket. If the watchdog is resetting, it's time to look at the VSM side of things. If it's not resetting, plug the monitor back into the harness and look for some video.
For the VSM, check the
PROM at C8 (C9 on Asteroids) and surrounding state machine signals
for HALT, DMAGO, STOP, GO and the like. The rest is pure grunt work
to check the state machine is running properly. Someone else please
feel free to add details to the VSM debug procedure...
ANSWER FROM email@example.com
The most fun bug in
the -01 version is to clear all but one rock and then get up to full speed
in a horizontal or vertical orientation; momentarily let off the thrust,
quickly flip around 180 degrees, and press the thrust again. You
will keep going full speed in that direction, but with your ship facing
the wrong way! (I believe you start by going left to right, or down
to up, and then flip around...but I may be remembering that wrong...)
Anyway, before someone
sells you an "authentic" one take a look at the