Picked up a one owner Centipede!

[jasonsmith]

Well we out to the local fun park yesterday and I got my kids to play a Centipede that they had there to see if they liked it. My son was all whatever but my daughter loved it so the mission which turned out to be a VERY short one began. I found a one owner machine that was on route to pay for schooling along with another 12 games. Great guy, just didn't have the room any more to hang on to them. He bought the machine brand new in 1980 for $3900 CDN.

It is in excellent shape, a couple dings but the artwork just like my Asteroid D is shiny bright and new looking. It has an original WILLIS CPO overlay which will clean up nicely I think.

It does have one issue though which you can see in the last pic. It plays though, just can't make out what you're doing. It has a WG K4600 in it which is my first game with one so no idea where to start.

Anyways enjoy and if you can lend a hand (again) that would be sweet.









And now the issue:



I'll get some side art pics when I get it out of it's hole that I stuck it in, running out of space 

[John's Arcade]

Sweet game!!! That Willis CPO is pretty bad ass! I wouldn't touch it! NICE GRAB!

[UnwoundS3GA]

Looks very cool!  ;) Do you mind showing us the side art? Is it pretty good? Looks like a monitor sync issue? 

[lordkahless214]

I love centipede, kinda looks like it has sync issues, I would start with a cap kit on the monitor and go from there.
Nice find!

Edit: of course now that i think about it, you should probably adjust the V hold and H hold potentiometers first and see if you can lock in a picture.

[jasonsmith]

Looks very cool!  ;) Do you mind showing us the side art? Is it pretty good? Looks like a monitor sync issue? 

This is the best I can do at the moment due to it's location.

[jasonsmith]

Edit: of course now that i think about it, you should probably adjust the V hold and H hold potentiometers first and see if you can lock in a picture.

Awesome, thanks, will give that a try.

[jasonsmith]

Playing with the Horizontal Hold fixed it and I was able to play for about 1 minute until the game play went nuts. The image looked fine but the score ended up at the bottom and gun was going bonkers and the sounds was crazy as well.

Did some voltage checks on the board and I'm not getting 36v at main PCB test point. The voltages on the AR2 board are a bit crazy as well. I think the poor girl needs caps and transistors all the way around.

For some reason the HV thingy were the focus knob is makes a high pitch whine, that's gotta be a sign.

[computerfixerguy]

That's a gem. Enjoy it!

[lordkahless214]

Yeah, sounds like you need to do the cap kits and ARII rebuild, maybe replace the big blue transformer cap

[jasonsmith]

Yep definitely a heat issue. After waiting for a bit and letting it cool off it played fine again for a few minutes then went bonkers again. There's something heating up and failing causing the issue. Sadly my test switch is broken so I test what circuit is failing.

A heating up failing issue doesn't seem like a cap though. Seems more like a resistor or something else??

Any ideas there? Whatever is failing causes the game play to go bad with messed up graphics but the monitor stability and colors seem just fine. Whatever is failing is effecting the main PCB I think?

[lordkahless214]

Well, you would actually be surprised at what bad caps can do. Heating/cooling cycles can, and often do mess with the capacitance causing all sorts of craziness, especially susceptible is the Big Blue.

Here are a few things you can try too, is the RF filter board still in place between the harness and PCB? many times filter boards can cause intermittent problems, so if it's still there you can try removing it and plugging the harness directly into the PCB see if that helps. Also, if you have a small fan you try running the game with the back door off and putting the fan blowing on the monitor, then power supply, then PCB and see if you can delay or stop the behavior, may help you identify where your issue is.

I always try the simple low cost troubleshooting measures first, which is why I usually throw a cap kit and, in the case of Atari's an ARII rebuild and Big Blue because it often clears up most issues, and if it doesn't it's pretty cheap and needs to be done anyway.

Good luck with it, if you have happen to have access to the KLOV forums maybe try there for even more suggestions

[jasonsmith]

Thanks for all the advice, I'm definitely going to try the fan idea. Going to do the cap kits anyway but would be nice to get it working stable.

[UnwoundS3GA]

Looks very cool!  ;) Do you mind showing us the side art? Is it pretty good? Looks like a monitor sync issue? 

This is the best I can do at the moment due to it's location.

Side art looks mint!

[lordkahless214]

I am having issues with my Millipede right now so I feel your pain, I'll keep doing some searching and see if I can come up with any other suggestions for you. I mean there are so many things can cause this, cold solder joints, thermal expansion.....

[jasonsmith]

...Also, if you have a small fan you try running the game with the back door off and putting the fan blowing on the monitor, then power supply, then PCB and see if you can delay or stop the behavior, may help you identify where your issue is....

Well gave this a try and put a fan onto the heatsink of the AR2 board and low and behold the games stays running. 

Thank you for the idea Mr. Lord.

Now it's a matter of figuring out what's going wrong. I think I'm going to change up the transistor first as it's directly in the fire and see what happens.

Then I just need to with some heavy warping on the left edge of the screen, thinking monitor cap.