DOA Centipede

[DarrenF]

The 36VAC is actually an input to the ARII board (from the transformer assembly, refer to Fig 15 in the Owners Manual). It is used to generate the +12, +22 -22 & -5VDC outputs. Make sure your meter is in AC volts mode when measuring the 36VAC line. Also: for AC measurements, you want one lead of your meter on each AC test point. This is different from DC voltage measurements, where you put the black lead on ground and the red on your test point. If you really have 0 (or 0.1) volts AC there, you would also be missing the aforementioned 4 DC voltage outputs. If the 36VAC really dead, you likely have a blown fuse in the xformer assy (I forget which one).

In either case, those voltages are only used for audio and high score saves. The single most important result is exactly what you measured on the +5VDC test point(s) on the game PCB. If it's not, say, in the 4.9 to 5.1V range on the game PCB, it may need adjusting (on the ARII).

PS, the two blue things near the 36VAC test points are called "capacitors." Specifically "electrolytic capacitors."

 

[FlavaDave]

Re:

Going into Radio Shack is like trying to order a pizza from Burger King.

 

[DarrenF]

Going into Radio Shack is like trying to order a pizza from Burger King.

More like "Cell Phone Shack" nowadays.

 

[cmkryzer]

Lol, Sorry guys, just was hoping to get parts quick..I will double check them pins, i check all of them on both boards, those were just the two the come up why different then what was listed on the board, didnt know i needed to change the multi meter. Still new at this i am..

I will report back later

 

[FlavaDave]

Re:

That is just what I have found out over the years, they look at you funny and your lucky if you find a capacitor from their wide lineup of 3 values. Love Centipede, I had a pretty nice one. Don't forget all the interlock switches are in the on position. There is one on the coin door, back, and maybe one other one if I remember. Good luck.

 

[cmkryzer]

That is just what I have found out over the years, they look at you funny and your lucky if you find a capacitor from their wide lineup of 3 values. Love Centipede, I had a pretty nice one. Don't forget all the interlock switches are in the on position. There is one on the coin door, back, and maybe one other one if I remember. Good luck.

Yep, both interlock switches are closed, coin door closed and the back one on the door i have taped closed.
Man i wish I had paid more attention in electronics class in high school.
I am still not getting it figured out on the 36 vac input pin....

 

[DarrenF]

That is just what I have found out over the years, they look at you funny and your lucky if you find a capacitor from their wide lineup of 3 values. Love Centipede, I had a pretty nice one. Don't forget all the interlock switches are in the on position. There is one on the coin door, back, and maybe one other one if I remember. Good luck.

I've made peace with Radio Shack. I ignore the ignorant staff (acting as if I don't understand English) and walk straight to the two cabinets near the back containing electronic components. Then they realize they can't help me, and go back to selling phones. I know what I can and can't find there. Mostly just: resistors, diodes, a few caps, a couple transistors, a few small molex connectors, and a few of the most common linear ICs (but nothing digital).

 

[DarrenF]

Yep, both interlock switches are closed, coin door closed and the back one on the door i have taped closed.
Man i wish I had paid more attention in electronics class in high school.
I am still not getting it figured out on the 36 vac input pin....

No need for tape. You can pull the plunger out, and it will say out (and the contacts are closed). If an interlock is open, you wouldn't get anything anywhere--no monitor, no marquee, no coin door lamps, no LEDs... nothing. If your monitor is showing garbage, your interlocks are fine.

Put the meter is AC volts mode, in range greater than 36V (say, 100VAC or 200VAC) if it's not auto-ranging. Put one lead (either one) on one of the 36VAC test points, and the other lead on the other 36VAC test point.

 

[cmkryzer]

Ok, another learned thing with the plungers. Well i got the meter figured out. And guess what, I got the 36vac on the test points. Well then, all test points checked out from what i see. Possible to still be big blue?
Any more ideas what to check. I have flickering of the screen and some garbled sound?

What ya think?

 

[FlavaDave]

Re:

It might be a board problem from the sounds of it. Take the connector off the pcb board, and clean the edge connector, put it back on. Look for chips with dirty legs, might even try reseating them. Look for bad caps too, and if all else fails it couldn't hurt to replace big blue. Don't take any chips out all the way out if you have never removed one before. You'll be sorry.

 

[toolguy]

One thing to remember about the test switch and the beeps. I've had the beep tell me a chip in my Asteroids was bad and in another machine the manual stated a chip was bad. In both cases, I replaced the said bad chips and the issue was still there. My point, dont rely strcitly on the test switch and beep to diagnose.

Possibly once the game is 100% up and running, it will test correctly, but not so in the early stages.

I would rebuild the AR board, get a new big blue and whatever else is rec for a Cent to be working properly. Do one repair at a time so you know when you put it all back together if something does not work again, what you just fixed caused another issue.

 

[DarrenF]

Ok, another learned thing with the plungers. Well i got the meter figured out. And guess what, I got the 36vac on the test points. Well then, all test points checked out from what i see. Possible to still be big blue?
Any more ideas what to check. I have flickering of the screen and some garbled sound?

What ya think?

I never did see you mention what you measured on the +5VDC test points on the game PCB.

Also, with the leads on the same points (+5V & GND), switch the meter over to AC voltage. What do you get? This is the "AC ripple voltage" riding on top of the 5V DC, and it is an indicator of the condition of the filter capacitors (incluging "big blue"). Even if you measure a perfect 5.0V in DC mode, too much AC ripple will cause flaky behavior of the game.

If your 5VDC is in the 4.9-5.1 range, and your AC ripple is low (less than say 30mV, or .030V), and the game still acts wonky... likely a game PCB problem; switch into test mode and let us know what you get.

 

[joeycuda]

Is R30 on the AR2 board burnt? Is the main PCB edge connector burnt (on the board side)?

 

[cmkryzer]

I never did see you mention what you measured on the +5VDC test points on the game PCB.

Also, with the leads on the same points (+5V & GND), switch the meter over to AC voltage. What do you get? This is the "AC ripple voltage" riding on top of the 5V DC, and it is an indicator of the condition of the filter capacitors (incluging "big blue"). Even if you measure a perfect 5.0V in DC mode, too much AC ripple will cause flaky behavior of the game.

If your 5VDC is in the 4.9-5.1 range, and your AC ripple is low (less than say 30mV, or .030V), and the game still acts wonky... likely a game PCB problem; switch into test mode and let us know what you get.

Ok, the numbers on the PCB board. That first top RH 5VDC right beside the plug in on the top, I ground it out and touch that first one, i got 4.9, then the are like nine points just to the lower LH from there, and those range anywere from 4.7to 5.1...Are these the ones you are asking about?

Also, the is one finger on the plug in part that looks like it was burnt, and some one bypassed the plug with a jumper wire, i will post a pic in a few...

 

[cmkryzer]

Is R30 on the AR2 board burnt? Is the main PCB edge connector burnt (on the board side)?

Nope R30 looks good....

 

[cmkryzer]

Ok, i just bought a known PCB board for this, gonna be picking up later this afternoon. We shall see what this brings.
Thanks for the help you guys have been suppling me!

 

[cmkryzer]

Ok got my replacement PCB board, wala we have a working game. But I did notice one problem, no marquee. I pulled it off ..and ..no light at all, last guy musta robbed it for something else. So if any one has one for sale, let me know.
Thanks again for all you help guys, I am sure i will be needing more in the future.

 

[FlavaDave]

Re:

Nice, what do you mean it's missing, the light itself or the whole fixture?

 

[cmkryzer]

Nice, what do you mean it's missing, the light itself or the whole fixture?

Yeah, the whole with is missing, you can see the out line where it was, but somebody removed it.

 

[RetroHacker]

There's really nothing special about the light fixtures in these games, it's just a fluorescent light fixture. The quick and dirty fix is just get an undercounter kitchen fixture and mount it in there. Looks exactly the same once the marquee is on.

-Ian