Build Your Own Arcade Controls Forum
Arcade Collecting => Miscellaneous Arcade Talk => Topic started by: rchadd on May 21, 2005, 03:29:07 pm
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anyone know what the highlighted board does in a centipede machine?
i just realized the cabinet i just bought does not have one :o
do i need one? :-\
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That is the power supply, known as an AR II board, and yes you need one.
I might have one in my closet, working condition unknown, but Bob Roberts sells a rebuild kit for them, that should get it back up to specs. If you are interested then you can have it for like $10 shipped in the US. I'll have to double check it and see if it is compatible though.
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That is the power supply, known as an AR II board, and yes you need one.
oh i thought the PSU was thing with transformer and the big blue capacitor
i thought it might have been the sound amplifier? :-[
actually the machine is already half wired to use a jamma loom and jamma psu
see my other thread http://forum.arcadecontrols.com/index.php/topic,37139.0.html
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That is the power supply, known as an AR II board, and yes you need one.
oh i thought the PSU was thing with transformer and the big blue capacitor
i thought it might have been the sound amplifier? :-[
actually the machine is already half wired to use a jamma loom and jamma psu
see my other thread http://forum.arcadecontrols.com/index.php/topic,37139.0.html
No, the thing with the transformer is the (wait for it) transformer assembly. The AR II board is a power supply with audio functions as well, just about all Atari games had them.
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The thing with the transformer outputs AC. That board converts it to DC, and also handles sound amplification.
You will need the AR-II revision specific to Centipede.
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would this board work with centipede?
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=6180092148
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Yep that will do it...
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Yep that will do it...
How do you know, considering the auction does not list a board revision number?
These boards ALL had the same primary serial number but then had "-01", "-02", "-03" etc... These were variations for certain games. You have to make sure you get the version for Centipede.
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well i hope it does - i'm currently winning
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You're missing your big blue cap, too... you have this green thing in its place.
;D
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no mine is big and blue
that is not my photo
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Check this list: http://www.elektronforge.com/AudioRegs.htm
Your Centipede needs a -02
If you don't win this auction, I have a couple defective -02's which you could buy a rebuild kit for.
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oh well won the auction...
just comparing the photos i think it might be a 02 board
although the big round things(??) are black and not grey
they both have square grey thing (??)
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Lucky you, it IS an 02.
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i am not sure what i should do at them moment re-wire with original psu or install a jamma psu
problem is that i do not have full wiring harness
i think i've got most of the power related loom
the part that had edge connectors and linked to the cpu board has been hacked up :(
i am not sure whether i am upto rebuilding the loom
how much different in value does having original psu and loom make to a machine?
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Personally, I only care that the machine works, but some people claim collectors want original hardware. I dunno.
How do you plan on using a switching PSU, considering the AR-II board also handles audio amplification?
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Personally, I only care that the machine works, but some people claim collectors want original hardware.
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I'm really confused here... Are you looking to get this machine working, or are you looking to refurbish it so it's more reliable? Or are you thinking making it JAMMA so you can swap in other boards?
Reason I ask, you say you are only missing the AR-II board. You just one one in an Ebay auction. Assuming it doesn't work, you need a rebuild kit which costs $12. But instead you're thinking of getting a $45 adaptor and new PSU. I don't understand...
:D
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Some people just want everything to be at least part JAMMA so they feel more comfortable.
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I'm really confused here... Are you looking to get this machine working, or are you looking to refurbish it so it's more reliable? Or are you thinking making it JAMMA so you can swap in other boards?
Reason I ask, you say you are only missing the AR-II board. You just one one in an Ebay auction. Assuming it doesn't work, you need a rebuild kit which costs $12. But instead you're thinking of getting a $45 adaptor and new PSU. I don't understand...
:D
no i don't want to run jamma boards in it.
really i bid on the AR-II board before thinking it through (as you saw i didnt even know if it was right revision)
i will wait untill the AR-II arrives and see if transformer + AR-II work together.
i dont have the whole wiring loom but i think most of power related stuff is complete.
if they do i will probably try to rebuild the missing loom wiring. if i can figure out the schematics. i am a bit worried i might be missing required molex connectors though.
i already have the cab half wired for the jamma and already have jamma psu installed in the cab - thanks to previous owner. getting the arcadeshop adapter looked like a plug and play solution for me especially at the time before i had an AR-II. i was going to have to order CPO from them any way. i only realised i would also need the updated EA-ROM just recently .
if i had the whole loom intact there would be no issue for me to go 100% original.
sorry to cause any confusion
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A'ight! That makes sense! :D
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Bob Roberts has the molex connectors if you are missing them and they are not all that much... I just finished wiring my centepede cab and had to find an ar-11 board myself....
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problem with bob roberts is that he doesnt accept paypal which makes it difficult for people living outside the US to order from him
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check?? money order??
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Just an FYI...
Old video games (pre 1985 for the most part) used *linear* AC transformers, with a secondary AC to DC conversion board.
The technology for newer "switch mode" power supplies had just entered the IBM PC computer world around 1981 and were extremely expensive so they wern't used in the beginning.
A large copper wound iron core transformer simply takes AC power and coverts it to either the same voltage (e.g. Isolation transformer) or a lower voltage like 5, 7, 12, 14 or 30 volts were the typical outputs of these supplies. Bally Midway, Atari, etc... all used similar but not identical ones.
The huge "big blue" (or multiple smaller but still large) capacitors were simply line noise filters to give a *somewhat* more fluid non-peaking/non-dipping AC frequency.
From the main power transformers, one goes directly to the monitor, it's called the isolation transformer. The other transformer likely has a 5 volt and a 12 volt output. But these voltages are AC not DC like electronic circuits require. Therefore it went to a secondard circuit board that typically had a few capacitors (filter noise), some diodes (to rectify the power--in other words convert AC to DC), and a couple large transistors mounted to a huge heat sink (to supply cleaner power when the AC voltage fluctates even with the capacitors), plus a few resistors that get quite hot that help keep the maximum voltage set.
From this board, the power then goes to the game board for 5 VDC chip logic and 12 volt DC audio amplification.
On most games, this is how it was set up.. e.g. all Atari, and most Midway (e.g. Galaga, Tron, Tapper, etc..) However the really old Midway like Galaxian and Pac-Man/Ms.Pac actually had the power board on the main circuit board and therefore AC power went directly into the gameboard. Of course this lead to frying of the traces on the edge connector since so many amps were being sent through it to get there. Later they converted to the separate boards (which also would die, but wouldn't require working on the main game board)
Finally around 1985, the replacement "switch mode" power supply came about. In a nutshell, it's identical to an old "AT" (pre-ATX) computer power supply, minus the fan. It doesn't use large AC transformers, instead it changes the frequency of the power (increases it) and then uses little tiny transformers instead, and converts it to DC and reduces the frequency back to 60hz. Usually they are controlled by at least 1 computer chip to provide a clean stable power source.
They don't take the place of isolation transformers for monitors, but do replace the large power transformer(s) and secondary power boards.
Therefore, in many games, you can rip out the large transformer/capacitors and the secondary board, and wire in a replacement switch mode power supply. On the positive side your board will run better and longer as you're giving it a MUCH cleaner source of power. On the negative, you usually have to hack your wire harness and what not to connect it in (though not too bad in *most* games), so you're no longer "original"---if that matters to you.
Specifically regarding the Atari AR boards.. They combine an AC to DC power conversion *and* the audio amplifier in one, so if you get rid of it, you'll need to put in an audio amplifier like out of a computer speaker system.
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check?? money order??
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20p for a money order? Are you SURE? I can understand high fees for wire transfers (they cost me about $30-40 canadian), but a bank "international money order" is only $5.
Bob Roberts won't rip you off, but he's been ripped off (hence why he won't take PayPal).
I agree with your arguments... I too prefer PayPal, but Bob Roberts is one of the few suppliers in town, so you don't really have much choice.
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Also, it is perfectly possible to tap an AR II as a general purpose power supply. I got my spare one out of a converted Nintendo cabinet. A guy I knew was reconverting it to Donkey Kong at a Superauctions, actually converting it right there on the loading dock. We noticed there was an AR II board hacked into the cab, I pulled it out and kept it (with his permission of course), while he finished converting it to Donkey Kong.