Omega Race: trying to exercise the demons..

vintagegamer

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So yesterday I got to tinker around with my Omega Race UR, and here's where I am:

1. I have 2 PCBs, and 2 power supply boards. When using either PCB or either power supply board, when I power up the machine, I briefly get the red LED on the main PCB lighting up, but it shuts off shortly after. Usually it's because the slow blow fuse on the power supply board has burned up.

2. when hooking up the main PCB, I first hooked up the edge connector as well as the 2 bottom connectors (a 3-pin and another one which I think is a 6-pin going off of my memory) and powered it up, resulting in what I typed in #1 above. I even tried replacing the fuse on the power supply board (whichever one I had in at that point) and hooking ONLY the 2 bottom connectors up on the main PCB (no edge connector), and the result was the same.

3. I wanted to check the connectors to see what voltages were getting to the main PCB, but I couldn't find a blasted ground tab anywhere on the main PCB to use (how I wish this was made by Atari), and reading the schematics for this game basically gave me a headache.

Additional points I noticed:

1. although I'm not getting anything on the screen, I did notice the red LED on the monitor chassis is on.

2. I can't get anything different to happen when the test switch is set to either option.

Any thoughts or input would be greatly appreciated! I want to see this thing live on!
 
First thing I would do is test each of your power supplies without anything connected to them. If they still blow the fuse, you can norrow it down to a problem with your power supply or the harness from the transformer.
Until you can get a board to play blind, leave the monitor disconnectoed to keep it protected and out of the equation.
*Measure the output from the power supply at connector "D" (on the power supply PCB). Put your black lead on pin 9, red lead on pin 3. You should see 5 volts or close to it there. Then put black on pin 8, red on pin 5. Again should be 5 volts. If not you have issues with your power supply.

*Please double check the schematics to make sure I have the pins correct.

I wouldn't even have try to troubleshoot a board before you confirm you have the correct voltage coming out of the power supply. If you want to check the voltages at the board at some point, you can put your negative lead on any of the screws that fasten the metal brackets together for the mother and daughter board. They are all connected to the ground trace around the board.
 
First thing I would do is test each of your power supplies without anything connected to them. If they still blow the fuse, you can norrow it down to a problem with your power supply or the harness from the transformer.

Last time I checked they were fine without anything connected to them. It was just when I brought the board into the equation that things started getting wacky. I will grab some more fuses and try again though.
 
If you want to check the voltages at the board at some point, you can put your negative lead on any of the screws that fasten the metal brackets together for the mother and daughter board. They are all connected to the ground trace around the board.

If you are referring to the triangular brackets that hold the 2 boards together, I don't have those yet. I was just trying to power on the main board without the logic/daughter board attached.

I will definitely check the power supply board as you mentioned as well. Thank you so much for the feedback.
 
Last time I checked they were fine without anything connected to them. It was just when I brought the board into the equation that things started getting wacky. I will grab some more fuses and try again though.


Fine as in "didn't blow fuses" or Fine as in "the voltages checked out OK?"

I have recently seen an MCR power supply look fine and not blow fuses, but output 6.75 volts when it should have been outputting 5 volts. Cranking the 5 volt adustment pot got the voltage up to 11.5 volts! That could quickly hose some chips on your OR board.
 
If you are referring to the triangular brackets that hold the 2 boards together, I don't have those yet. I was just trying to power on the main board without the logic/daughter board attached.

I will definitely check the power supply board as you mentioned as well. Thank you so much for the feedback.

That just raised a red flag! I'm not positive what the results of this would be, but the 5volt sense line goes through the duaghter board. Without the daughter board attached, it may send an excessive amount of juice to the motherboard and pop the fuse on the power supply.
 
That just raised a red flag! I'm not positive what the results of this would be, but the 5volt sense line goes through the duaghter board. Without the daughter board attached, it may send an excessive amount of juice to the motherboard and pop the fuse on the power supply.

INteresting!! Thanks again for the help!
 
Hoping to tinker with this again tonight so, if anyone has anything else they recommend trying please let me know.
 
Hoping to tinker with this again tonight so, if anyone has anything else they recommend trying please let me know.

Do you have the daughter board and the metal brackets?
First, I would confirm good voltages out of the power suppply board, then connect the daughter board and all connectors (the test switch also connects through the daughter board) put it in test mode and fire it up.
If there are ram errors, you will get flashing start lights and beeps to tell you which chips are bad. The manual will tell you which ram chip it is refering to.
Reseat or replace any that are flagged bad and try it again.
 
Daughter board has to be on. Its extremely rare to ever get an OR to give you anything when its not working, but you may get some ram tones. Buy some new ram, because you will need it. Its also recommended to swap out all the eprom sockets with new ones as the ones Bally used were crap.
 
OK here's the progress I've made as of today!

Finally figured out which schematic corresponded to my machine, which is on pg 100 of the manual:

1. voltages for the 6-position connector of the motherboard all check out as they should be. The voltage for the yellow/red unregulated 8V line has a voltage of 9.8V. I'm still not sure though if the 3 pin connector should go in the order of orange, black, green on the board connection, or vice versar (need to determine which pin is "1" on the motherboard)

2. I made sure I had all of the connectors on the daughterboard connected correctly

When I power up the machine now, it's still blowing fuses when the boards are connected (no blown fuses when just the power supply board is powered on) BUT, I noticed today that the control panel is getting power (all 4 led's to start the game are lighting up). The sad part is I only get between 10 and 20 secs to check things before the fuse goes..

Questions:

I don't have the triangular brackets that hold the daughterboard in place on the motherboard in addition to the edge connector. Are they working as grounds as well as supports? Could this be where I'm having power issues?

I really want to bring this thing back to life but, at 3 bucks per 2-pack of fuses, I don't know how much longer I can keep trying this :(
 
Last edited:
Do you have the daughter board and the metal brackets?
If there are ram errors, you will get flashing start lights and beeps to tell you which chips are bad. The manual will tell you which ram chip it is refering to.

Lights where? Do you mean the LED on the board? Or other lights (ie on the control panel)? I'm looking through the manual right now for this info as well.
 
OK here's the progress I've made as of today!

Finally figured out which schematic corresponded to my machine, which is on pg 100 of the manual:

1. voltages for the 6-position connector of the motherboard all check out as they should be. The voltage for the yellow/red unregulated 8V line has a voltage of 9.8V. I'm still not sure though if the 3 pin connector should go in the order of orange, black, green on the board connection, or vice versar (need to determine which pin is "1" on the motherboard)

2. I made sure I had all of the connectors on the daughterboard connected correctly

When I power up the machine now, it's still blowing fuses when the boards are connected (no blown fuses when just the power supply board is powered on) BUT, I noticed today that the control panel is getting power (all 4 led's to start the game are lighting up). The sad part is I only get between 10 and 20 secs to check things before the fuse goes..

Questions:

I don't have the triangular brackets that hold the daughterboard in place on the motherboard in addition to the edge connector. Are they working as grounds as well as supports? Could this be where I'm having power issues?

I really want to bring this thing back to life but, at 3 bucks per 2-pack of fuses, I don't know how much longer I can keep trying this :(

1. I think you are OK with the 9.8 on the 8v unregulated line. The "unregulated" part means it can fluctuate +/- around 8 volts.
As for the orientation of the 3 prong plug, in this case it doesn't matter. The schematics show that the center is common and the two outers are 18v. No matter which way you put it on the voltages would be correct. That said, you should look at the keyed connector right below it and match the orientation of it.

2. It sounds like you have a short on the board drawing too much current.
I would closely examine the bottom of the board for shorted pins. All of the OR boards I have seen have pins that are far too long on the bottom and if they are bent over can contact other traces/pins. Also, check the top of your board closely. The small transisters can get squished down and the legs will short together.

The metal brackets are working as grounds, but looking at the schematics, the ground is also run through the large connector between the mother and daughter board.

Next step would be to check the board for shorts. Also, check the harness out and make sure there isn't a quarter sitting on top of two fuses or something like that ;)
 
If I can get out there tonight to tinker some more, I will do what you have advised below and report back.

I also do not have all of the chips in the main board yet. I have been transferring them slowly from another more-deteriorated board to this one, and so far have only swapped over the ROM chips. I will put more of the chips in and provide an update regarding that as well.

Thanks for the help!


1. I think you are OK with the 9.8 on the 8v unregulated line. The "unregulated" part means it can fluctuate +/- around 8 volts.
As for the orientation of the 3 prong plug, in this case it doesn't matter. The schematics show that the center is common and the two outers are 18v. No matter which way you put it on the voltages would be correct. That said, you should look at the keyed connector right below it and match the orientation of it.

2. It sounds like you have a short on the board drawing too much current.
I would closely examine the bottom of the board for shorted pins. All of the OR boards I have seen have pins that are far too long on the bottom and if they are bent over can contact other traces/pins. Also, check the top of your board closely. The small transisters can get squished down and the legs will short together.

The metal brackets are working as grounds, but looking at the schematics, the ground is also run through the large connector between the mother and daughter board.

Next step would be to check the board for shorts. Also, check the harness out and make sure there isn't a quarter sitting on top of two fuses or something like that ;)
 
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