DOA Centipede

cmkryzer

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Hello fellow arcadians, I just brought home a centipede full size cabinet that has start up issues. Seeing I am new to this site and seeing how very helpfull you all are, I was hoping I could get some help in getting the baby up and running. The old owner stated jst one day, it fail to power up. what i get is when its plugged in, There is a faint light in the player one and player two buttons and the screeen is all garbled for a second then goes blank. Now it this maybe a power issue?
Now please, me being new to the innards of the games, i will need to be walked through and help that you can give me. I know with all your help, we can get this baby up and running. So where do i start! Fire away!
 
Sounds like your power supply may be the first thing to check. Obtain a multimeter and check the test points on the little circuit board with the big heat sink on it, thats your AR/II and they are common failure points for some Atari games. Check your voltages and report back!
 
Step zero.

Download the owners manual: http://arcarc.xmission.com/PDF_Arcade_Atari_Kee/Centipede/Centipede_TM-182_6th_Printing.pdf

Atari wrote pretty good manuals back then. They are worth reading. I recommend reading it cover to cover. Twice. Pay special attention to the diagrams and terminology. This will help you understand the general anatomy of your game, and permit you and other posters here to speak the same language when refering to parts.

Then proceed to checking your fuses & voltages.
 
Agreed with the previous posters, but I thought I'd add a couple things.

Even if you're getting "close enough" values in the voltages, there may still be a power-related issue. I was recently troubleshooting my own Centipede machine, and all the voltages off of my AR/II looked good. The problem turned out to be a bad "Big Blue" capacitor. I was getting garbage on the screen for a very brief moment, followed by solid colors. I thought it was a bad board, but after putting it in another KLOV member's working cabinet, we discovered that the board was just fine. He happened to have a spare big blue on hand that he gave to me, and that fixed everything!

http://www.therealbobroberts.net/bigblue.html
 
You picked an excellent game as your first repair job. Centipede is one of the simpler and most reliable games. You probably have a power supply problem, as others have said. The test points are marked on the ARII board. The ARII is the audio amplifier and power regulator for the game. It takes 10.3vDC (unregulated) from the power brick at the bottom of the game, and converts it into the 5v and other voltages needed by the game board.

Start by checking the 5v test point. It's probably going to be low, with the symptoms you describe. Then, check the 10.3v test point. If that is low, or jumping around, then your problem is in the power brick in the bottom of the game - most likely the large blue capacitor (a very common failure). The capacitor is easy to change - you only need a philips head screwdriver. Just mind the polarity when you install a replacement. Replacement capacitors are available from Bob Roberts.

Other common failures include the ARII board itself (caps and regulator transistors), the rectifier block in the power brick (but that usually blows fuses and causes a totally dead game), the fuse holders in the power brick, and the edge connector on the game board.

But, start by using a multimeter and checking the voltages and report back. I have no doubt that we can get you running again.

-Ian
 
Even if you're getting "close enough" values in the voltages, there may still be a power-related issue. I was recently troubleshooting my own Centipede machine, and all the voltages off of my AR/II looked good. The problem turned out to be a bad "Big Blue" capacitor.

After checking/verifying/adjusting correct (average) any DC voltage, switch the meter over to AC voltage mode. This will measure the AC ripple component riding on top of the DC voltage (http://upload.wikimedia.org/wikipedia/en/7/7e/Smoothed_ripple.svg). If the filter cap ("Big Blue") is bad, it will manifest itself as a significant AC component. In general, I'd say less then 0.030V (30mV) is probably OK. If you have more than 0.1V (100mV), it's likely a problem. (Perhaps other guys here will have other recommended ripple limits.)

Usually the +5VDC line is most sensitive to AC ripple, as it's used to power all of the logic ICs. Other DC voltages (e.g. -5VDC, +12VDC) can usually tolerate more ripple, but it may cause audio humm.
 
If you find the power board good and big blue has been replaced and you still have garbage on the screen, try powering it up with the test switch on... and count any beeps. Beeps will indicate specific memory chips if you have a failure.
 
Boy you guys are great, with all the info you guys are giving me, I could build one of these things.
Well maybe not.. but close.

Now if i can just get out of work today so i can get home and work on it.

You know , I am a 40 year fat slob, and i feel like a kid at christmas time, i just cant wait to get home dig into this machine and bring her back to life..

"hey boss, I dont feel so good, cough cough, can i have the rest of the day off??"
 
Ok, stopped and got a mutli meter on my way home from work, down loaded the manual, read through it. Not really sure where the check points were to check voltages. I kind monkeyed around, found the test button, and turned the volume up to hear the tones, i get two loud beeps nd thats all. I thought i read somewhere on here that means something is out. Also heard some clicking when i turned on the power and then a pop when off. Here is is something that is tied on to the wire harness for the coin door that i think comes together when powered on, then opens when off. The whole wire harness was not hooked up just taped up against the wall. I will try to post pictures later.
Please help, be precise on where to check numbers...
The old owner says it would one day, then just didnt work the next..... so not sure what could have went..
 
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Ok...more reading, manual says 2114 chips are bad. Is this something the local radio shack will have ?
 
Ok...more reading, manual says 2114 chips are bad. Is this something the local radio shack will have ?

Highly doubtfull Radio Shack would have the chip.

The two biggest places to get parts from are:

http://www.mouser.com/?utm_source=y...D=6683546522&OVADGRPID=11525785910&OVNDID=ND1

http://www.therealbobroberts.net/

Other places are:

http://www.pacmandotcom.com/

http://www.arcadechips.com/



How are your soldering skills? If you have never unsoldered and soldered chip before, this may not be a good way to learn. You migh be best sending the board out and then youself focusing on the non-electronic parts of the machine. I only say this because if you've never soldered before, you can cause more damage to the board.

You can also get junk boards and practise on before your Cent board.

Might want to make a list of other parts you might need or want to replace on the board before buying the chip. Lets face it, most of these games still have their 25-30 old original electronics, and they don't last forever.
 
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If they aren't socketed, you can *try* piggybacking the SRAM to test. May not help, but it won't hurt anything.
 
cmkryzer said:
Ok...more reading, manual says 2114 chips are bad. Is this something the local radio shack will have ?

I know the self test gave you the errors, but have you checked the power supply yet? Any onboard diagnostics are useless if the power supply isn't working correctly.

If the power supply is working, and you do need to replace those RAM chips, then no, Radio Shack will not have them. Toolguy gave you a lot of great places to buy them though.

And if you've never done any board level soldering before, you should really practice on something first. Desoldering and removing a chip from a double sided board is tricky if you've never done it before, and it's easy to gouge, lift or otherwise destroy the traces and pads on the board. One thing that will make it easier is to clip out the bad chip first - clip all the legs close to the chip, and desolder them from the board one at a time. That'll minimize the chances of ripping up the board.

You should also install a socket - this prevents damage to the chip by overheating it, and it means that you'll never have to desolder it again if it fails, or the chip is defective.

There's always a chance the RAM in this board is already socketed, but it didn't come that way from the factory.

-Ian
 
Ok...more reading, manual says 2114 chips are bad. Is this something the local radio shack will have ?

Unlikely that RS has them (just looked online) but you can call them.

Try here:
http://www.pacmandotcom.com/

And it is NOT unusual for a game to be working one day and just not the next. Your game is ~30 years old and has many components in it. One fails, and you have anything from an unnoticeable bit wrong in a graphic to your case, complete failure. Now you just have to find that one!

I would unplug the game board and check voltages on the A/R II (Audio Regulator board, version 2, I think), the small board near the bottom of the cab.
 
I've only been in this hobby for a couple of years, so my electronic troubleshooting skills aren't up there like most. My solution, Just bite the bullet, order the rebuild kit for both the AR board and the Power Brick from Bob Roberts. While you're at it, get the new power cord too. Bob makes this repair a no brainer. I do this for all of my Atari games, and haven't had the first problem.

Also, if your track ball is a little rusty, get the roller kit from Bob. I recently did this on my Centi and its smooth as butter. =)
 
I've only been in this hobby for a couple of years, so my electronic troubleshooting skills aren't up there like most. My solution, Just bite the bullet, order the rebuild kit for both the AR board and the Power Brick from Bob Roberts. While you're at it, get the new power cord too. Bob makes this repair a no brainer. I do this for all of my Atari games, and haven't had the first problem.

Also, if your track ball is a little rusty, get the roller kit from Bob. I recently did this on my Centi and its smooth as butter. =)

yeah, i checked his site out, looks like he has what i should need. As far as the track ball, yes mine needs attention, very "gravely" when rolling it , may be the bearings going out but wanna get the thing running before i take on that job
.
Thanks for the advise!
 
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Where can i find the points i need to check ?

On the ARII board, there are labelled test points for the 10.3v, and others. You should really check the 5v at the game board. There should be marked test points threre too. Or, you can always check at one of the ROM chips or something.

-Ian
 
Most of my AR & ARII PCBs didn't have the test point "loops" installed at manufacture. So it can be a bit of a pain (with everything hooked up) to look at the schems and find a component let which should be at the voltage you're looking for. I'd just unplug J7, and probe the voltage in there (pins 5 & 6 should be +5VDC relative to pins 1 & 4).

However, as you point out, what's more important is what the +5V is on the game PCB; and those always have the test point loops installed.

Look for burned and/or corroded pins on those connectors, and on the game PCB edge connector too.

BTW, I think you can safely ignore all of the other voltages the ARII generates (-5V, +22V, -22V & +12V) at this point, as those aren't necessary for the game to (minimally) run. They are for other things like, high score saving, audio pre-amplification, etc.
 
Ok guys, I figured how to check the test points. I checked them both on the game pc board and on the arII board, the most noticeable is on the upper top where ther is suppose to be 36vac on two test points, just above thebig two blue resistors? The very top is .1 and the lower of the two comes up zero...
So what you guys thing?
Any thing else I should check ?
 
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