Tony's Arcade

Well, Asteroids went on the fritz. I have been happily playing it (and getting shamefully beaten by Fred.) The other day I powered on Asteroids, and the screen starts flickering, and the game resets every couple of seconds. Then, the screen goes blank, and the Player 1 and Player 2 buttons start flashing rapidly — flashing more quickly than when in “free play” mode. I read this happens when the reset circuitry keeps activating, constantly resetting the game. Ugh! I quickly turned off the game. I thought maybe the voltage regulator had gone bad — I unplugged the main board and tested the +5V on the AR (Audio/Regulator) board. Asteroids and Asteroids Deluxe used the “AR1″ (as opposed to the AR II, used in many Atari games such as Pole Position, Tempest, and Star Wars.) You can see a comparison of the Atari Audio/Regulator boards at Elektron Forge. The AR1 regulates the +5V going to the main board below. Turning the voltage adjustment pot would not allow me to bring the +5V below 5.6V. I thought that maybe the voltage regulator was the problem. (I later found that measuring the +5V on the AR1 board without plugging in the monitor and main board is not a good way to measure voltages. Not having a load on the AR1 board will give higher voltage results. So, the voltage regulator wasn’t necessarily the problem — I misdiagnosed that one!)

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The Asteroids cabinet has two locations for speakers above the monitor. At first, I thought there were two speakers up there as the AR (Audio/Regulator) board has SPKR1 and SPKR2 test points. While playing the game, I noticed that the sounds were only coming from the right side. I opened up the cabinet behind the marquee (using a 1/8″ hex wrench, by the way) and saw there was only one speaker! I did some research, and I found that Asteroids only used one speaker. One person on rec.games.video.arcade.collecting suggested that the empty speaker location might be an acoustic vent port. As for the SPKR1 and SPKR2 test points, it appears the mono audio output is amplified twice.