Asteroids - not enough voltage on AR board

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Hi folks. I have a couple of basic level questions on a voltage problem I am having with Asteroids.

First, I have been doing some reading of various threads on here and they have been a big help...I got to the point of where I am now just by learning from others. Thank you community.

This Asteroids game was in my storage for like 15 years and I was finally able to retrieve it and bring it home....across the country.

Game doesnt play. No surprise. So I started checking connectors, etc. I used some electrical spray on the molex connectors and got the machine to hum through the speaker now..where it would not before I sprayed it...so progress there....

Questions:

1. There is an LED light on the Asteroids PCB board. It does NOT light up except when you either power on the game or power off.

2. After watching videos, I tested the AR board. I found I am getting 12vDC just great but only getting 1.5vDC on the +5v side. So I am not getting 5v to the game, presumably...and probably why the LED light is not on....and why the speaker hums...

Does this sound like a cap kit for the AR board?

3. I am getting AC for the coin door lights. The monitor neck has glow and the LED light on the monitor chassis is on full time. (unlike the game pcb)

4. The marquee light does not work but on that there is a loose wire going to the ballast to fix or I have a bad ballast...parts are enroute. (tried swapping tube and starter already)

5. All fuses have continuity and are good...I have not cleaned the area just yet but I did shop-vac the dust out from inside...tons of old mice bedding inside.

6. And last, I did spray the edge connectors for the game PCB...but I think my issue is voltage at this moment.


So analysis, anyone? The AR board is really suspicious to me right now.


Thank you!
 
Thanks Andrew. I sent you a PM.

Would that lack of 5v trigger the symptoms? (just wishing to confirm)

1. humming from speaker
2. LED light off on the PCB except when flipping the power switch on or off, then it flickers on briefly.

And I am going to try the pot adjustment so I can be complete with what I have...though not sure if it will end up working or not.

Robbie
 
Your AR isn't putting out 5V, so your game board is dead (as that's what the red LED on it indicates. It's the 5V LED.)

You need to fix that before looking further into the audio issue, as the board isn't putting out good audio (or anything) right now. If the audio is still bad after fixing the 5V, it could be other things, typically a bad TDA2002 amplifier on the AR. But you can't confirm that until you know the game board is working.
 
Your speaker is humming because there is no output to the speakers as the game pcb isn't being powered on due to the lack of +5v. I doubt turning the VR pot on the AR2 will fix this. I would personally leave it in it's original position.

Like Andrew said, you really need to sort out the AR2 first, starting with the 2N3055 transistor and Tip32 checking for bad resistors on the +5v rail.

You can temporary sense mod the AR2 so you can test and adjust correct +5v (the Pot) before plugging in the PCB in once you fixed the AR2. I normally just leave the sense mod in afterwards and just make sure my edge connectors are kept clean.
 
if your not going to buy another AR from andrewb than i have the complete cap and rebuild kits for that all the AR boards. if you don't want to rebuild yours than i would definitely recommend buying the whole AR1 from andrewb.
 
Your speaker is humming because there is no output to the speakers as the game pcb isn't being powered on due to the lack of +5v. I doubt turning the VR pot on the AR2 will fix this. I would personally leave it in it's original position.

Like Andrew said, you really need to sort out the AR2 first, starting with the 2N3055 transistor and Tip32 checking for bad resistors on the +5v rail.

You can temporary sense mod the AR2 so you can test and adjust correct +5v (the Pot) before plugging in the PCB in once you fixed the AR2. I normally just leave the sense mod in afterwards and just make sure my edge connectors are kept clean.

+1 on keeping your edge connectors clean. I've been pushing this for several years now. it's particularly important on Atari games with Sense as a dirty edge connector will produce a cascading effect that inevitably burns up the edge connector. it's a combination of Sense trying to step up the voltage on its own to compensate from the resistance produced by a dirty edge; that resistance turns into heat.

I need to track down a schematic for these for my own needs. I have the full Tempest manual at work, are the AR and AR2 +5 circuits pretty much the same, or isn't AR1 the same as AR2 just minus the opposite side?

the circuit should be relatively simple though. though if the 3055 were bad, wouldn't that short produce 14 volts down the 5 volt line? I'm leaning more towards an open resistor or perhaps bad solder. those resistors should generate a lot of heat to break down the solder joints.
 
I need to track down a schematic for these for my own needs. I have the full Tempest manual at work, are the AR and AR2 +5 circuits pretty much the same, or isn't AR1 the same as AR2 just minus the opposite side?

The +5 sections are basically the same for AR-II's and AR-I's. And yes, an AR-I is, generally speaking, and AR-II without the right side. EXCEPT for the audio circuit, which is slightly different.

An AR-I-03 (Asteroids Deluxe) is fully identical to the left side of an AR-II-01, for both sound and power. However and AR-I-01 (Asteroids) has a larger gain for the audio amplifiers, because Asteroids boards output a weaker audio signal. So, if you try to run an Asteroids board in an AD cab, the sound will be quieter. (And if you try to run an AD board with an Asteroids AR, the sound will be overdriven and distorted).


the circuit should be relatively simple though. though if the 3055 were bad, wouldn't that short produce 14 volts down the 5 volt line? I'm leaning more towards an open resistor or perhaps bad solder. those resistors should generate a lot of heat to break down the solder joints.


This is true, however more often than not, the 2N3055's just get tired and/or go open, resulting in 0-0.5 volts at the output.

That's not to say the 3055 is the only part that can go bad, but it's the most common, and the first place to start if you don't have the ability to go though and test every component. If it's not the 3055, the LM305 regulator is next, followed by the TIP32 (which I personally have never seen one bad, but that's not to say it can't happen).

All of the other passive components pretty much never fail on their own, unless they're physically damaged. If you do see any burned resistors, they're typically a secondary failure, resulting from something else going bad (either on the AR, or elsewhere in the cab).
 
Thanks all..great replies...good to have confirmation on a few things...

Andrewb, I sent you another PM.

I hope it is for another AR board. Get a kit for yours and fix it yourself. You will learn so much more. It is more rewarding when you learn to repair your own game.
 
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