Omega Race work in progress

Pimpbot5000

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So I picked up an Omega Race in November and have been slowly coaxing it back to life. I knew this would be a huge project, but that's kind of what I was looking for... something to tinker with and learn how to troubleshoot. Plus it's a great game that I played a lot when I was a kid.

The motherboard had the typical acid damage:
CIMG4744.JPG


I cleaned the board up as best as I could. The worst portion of acid damage had destroyed several circuit board traces:
CIMG4763.JPG


I installed new sockets for the RAM chips and added jumpers to fix the circuit board traces. This is kind of ugly; it was my first time doing something like this.
CIMG4871.JPG


After doing all of this, the board was still completely dead. At that point I noticed that the crystal was missing from the board. After replacing the crystal the board came back to life. I replaced a few more acid-damaged chips, added some more jumpers, and got the board to the point where I could coin it up and play it blind. This was huge for me; I think I probably picked one of the most troublesome games on which to learn PCB repair.

Unfortunately the self test is reporting RAMs 10 and 12 as bad, and I can't figure out why. I've checked all the address and data lines for continuity and I can see them pulsing with a logic probe. So I'm currently stuck on that problem.
 
I decided to go ahead and see if I could get the WG v2000 monitor working. I replaced the HV diode, the frame-mounted transistors, and the caps on the HV and deflection boards. The first time I fired it up I had a picture, and I could see the Omega Race attract mode, although it was jumpy. However after a few minutes the picture went out and the deflection board caught on fire :)

CIMG4937.JPG


It turned out that R613 and R618 had burnt up. I ended up replacing a bunch of components in the Y section of the board, and finally got the monitor to come back to life, and to not catch on fire.

My problem now is that the vectors are wavy and misaligned.
CIMG4997.JPG


It's kind of difficult to take a picture of, but the text seems compressed on itself.
CIMG5001.JPG


At this point I'm not sure if I have a monitor issue or a board issue or both. During the few minutes that the monitor worked the first time, the text was much more legible and the ship vectors were aligned. Now, not so much. Unfortunately I don't have an oscilloscope or another game in which to test this monitor.

Video here:


So, to summarize where I'm at right now:
1) The game plays, but the self test reports RAMs 10 and 12 as bad.
2) The vectors are wavy and misaligned.

I could not have even gotten it to this point without scouring KLOV for information and pouring over a ton of great posts. If anyone has any suggestions for where I should go from here, that would be awesome. Thanks!
 
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Good luck with it. I swore off repairing them. After the last 3.. Then I wound up getting two more. Ugh...

Double check all your traces for the rams for continuity, and make sure that none are shorted.
 
Omega Race is very much worth it once you get past the initial hump of getting it going. I would never let mine go. You have made some great progress, here's hoping you can get it going all of the way!

Looks like a PCB issue to me.
 
omega race

I have been working on getting mine going too. I'd suggest you replace the 2 TL081's & 2 TL082's as well as the 2 4016's with new socketed chips. They are cheap from Bob Roberts or Twisty Wrist. Anyway they helped clear up a ton of issues in mine though it still has problems...

Here's a link to the thread om mine.

http://forums.arcade-museum.com/showthread.php?t=210479&highlight=omega+race
 
ScottMaggie, I've been watching your thread closely. It seems you and I are in the same boat! I ordered the op amps and 4016's, I'm hoping they help! Thanks, and I hope you keep making progress on your board.
 
ScottMaggie, I've been watching your thread closely. It seems you and I are in the same boat! I ordered the op amps and 4016's, I'm hoping they help! Thanks, and I hope you keep making progress on your board.

Ditto;

I am impressed with your progress and the jumpers look fine.
 
Well I replaced the TL081s, TL082s and 4016s with no change to my video problems.

I feel like I need to figure out why I'm getting RAM errors before I do anything else. I should clarify that when I said the self test was reporting RAMs 10 and 12 were bad, what I actually meant was that I'm getting 10 beeps, and then 12 beeps. According to the manual this corresponds with video RAMs 2 and 4, which are chips J-1 and/or L/M-1, and J/K-1 and/or N/P-1.

When I remove RAMs J-1 and J/K-1 I get the same error... this leads me to believe the problem is with those chips. Not sure if that logic is valid.

I've double and triple checked the continuity across the address and data pins on all the RAM chips, and I've checked for shorts. I'm having a hard time finding the problem. How likely is it that the problem is with a chip downstream from these chips?
 
I had same beeps...

First, switch the RAM around with ones not showing up in the error codes. If the codes change then you know the RAM's were bad.

Next notice that although the leads from RAM to RAM on the board look exactly the same the pattern actually changes slightly. That's where my 10/12 error was. My acid damage was so bad that some traces were totally gone. Attached is a photo I took from one of Omegaman's posts. You will notice the pattern changes slightly between the RAM's. Use this to make sure you didn't jumper some pins that should actually not be connected.

This cleared up my LED / RAM errors 10 & 12. I have since fixed a couple of diodes. Waiting on some new video ROMs hoping mine are corrupt causing my last graphics issues. (keep fingers crossed)

Also, if you have a Pacman or Ms. Pacman you can test the RAM's in there too.


EDIT: Just went back to the top of this post and see your great pic of the cleaned up board. Compare that pic to the one I attached and make sure your jumpers didn't cover something that should be blank.
 

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Scott, thanks for the help. I went back and checked my jumpers again and you were right, there were a couple of mistakes. I fixed those and had it down to just 10 beeps (video RAM 2). Then I continued to mess with it, and of course I made it worse. Now I'm getting 10, 13 and 14 beeps (video RAM 2 and video ROMs 1 and 2). It's kind of driving me crazy.

Current jumper configuration:
CIMG5063.JPG


CIMG5064.JPG
 
OR: better - worse - better

I did the same thing. Took me a few tries to get it right. I actually re-did all the jumpers 3x before I finally got no more errors.

Since you were able to get 1 of the codes to stop you know at least you can get back to that point. This is exactly why people hate working on OR.

Suggestion:
Remove 1 jumper and test the board. If no change, put it back. Do this over and over until you find ones that were incorrect.

Good luck & keep us posted!


PS: My new ROMs are on the way so I'll have an update on mine soon...
 
your last photos

On a quick glance at your last photos here is a couple of spots I'd check. They look like they could be touching the traces under the jumpers.
 

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On a quick glance at your last photos here is a couple of spots I'd check. They look like they could be touching the traces under the jumpers.

Not only that but it looks like you bridged the solder pad to the trace next to it on the red wire in the upper right corner of that picture.
 
On a quick glance at your last photos here is a couple of spots I'd check. They look like they could be touching the traces under the jumpers.

Wow dude, good eye! The third connection that you circled was shorted. I had just re-done those around 1am last night. I fixed the short and BOOM, it now passes the self test! Thanks so much for taking the time to look at my stuff.

So, now on to the next problem. :)

The video is still messed up. I think as my next step I need to find someone to either loan me an oscilloscope or let me plug my monitor into their game so I can narrow down where my problem is.

Test pattern:
CIMG5065.JPG


Attract mode demo:
CIMG5066.JPG


Attract mode points screen:
CIMG5067.JPG



The other thing that's messed up is the explosion sound when the player dies. Instead of fading out, it plays the whole thing at full volume, way louder than any of the other sounds.

Anyway, it's getting there.
 
horray for progress!

Glad you found it and are now up to the same spot I am though our graphic issues look different.

Are the images clear on half the screen or goofy all over? You can test the monitor in an asteroids, asteroids deluxe, battlezone all direct plug and play...


As for the sounds....there's two volume controls on the daughter board. I'm guessing the one with the explosions is turned up.
 
Not only that but it looks like you bridged the solder pad to the trace next to it on the red wire in the upper right corner of that picture.

Thanks for pointing that out. I had actually noticed that as well, and I confirmed on a parts board I have, it's supposed to be bridged like that.

CIMG5068.JPG
 
Glad you found it and are now up to the same spot I am though our graphic issues look different.

Are the images clear on half the screen or goofy all over? You can test the monitor in an asteroids, asteroids deluxe, battlezone all direct plug and play...


As for the sounds....there's two volume controls on the daughter board. I'm guessing the one with the explosions is turned up.

It's pretty much goofy all over. The thing that bothers me is that in the five minutes before my deflection board got fried a while back, I actually saw the attract mode clearly. So I'm thinking I still have a monitor issue. This is what I replaced on the deflection board to get it up and running again (it's a v2000):

R605 470 Ohm 1/4w
R608 470 Ohm 1/4w
R613 27 Ohm 1/4w
R614 1k Ohm 1/4w
R618 10 Ohm 1/2w
D606 Diode IN914
D607 Diode IN914
Q602 Transistor (NPN) TPS 98
Q603 Transistor (NPN) TPS 98
Q605 Transistor (PNP) 2N3906

With the sound, the volume control for that speaker does have an effect, and the other sounds from that speaker are at a normal volume, but the explosion sound is always 10 times louder. There is some distortion on one of the sounds in the sound test as well.
 
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OR...

Your photo of the attract mode shows the outside "box" top right instead of all around. On mine I think the TL081's & TL082's as well as the 4016's fixed this. I know you replaced those - check them. Since there are 2 of each chip you can swap them one at a time and see if the issue on the screen moves around.

Also since you still have a RAM code might possibly be from that though I am learning that any number of chips could be causing the grief we are both suffering with OR. :0(

Back to the sound - swap the 2 AY-3-8912 and try the sounds again. See if the problem moves elsewhere rather then the ship explosion. If it is still the explosion sound then the 8912's are good if it moves then one is bad. If the explosion doesn't move next thing to swap would be the Z80 for a known good one.


PS: On the monitor - get the cap kit and a spare HV diode. Still, you really want to test it in another game so you don't have to think about it again. Surely someone in Atlanta has a game with an 19V2000 that Pimpbot can test his monitor in? Bueller? Anyone?
 
Well I swapped the AY-3-8912 chips and the explosion sound is now fine, but the fire sound is missing. So it looks like one of those is bad. I've ordered a new one.

So the only thing left is my graphics mess. I'm hoping one of the local collectors will let me plug my monitor into one of their games so I can be sure it's working properly. I'll post an update when that happens.
 
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