Atari Football Power Problem?

Nintendork

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Hey guys. I have this Atari football that I got working . Had to replace big blue and she fired up also did a cap kit on the Motorola monitor. Everything works except for there are some glitches on the screen however when I test the voltages I get good voltage on everything except for the plus five I am only getting about 3.5 and I believe it is causing the game to glitch in this way (pictures). Since there is no pots to adjust what would you suspect would be the issue? This is my oldest game I've ever repaired so I definitely am out of the loop.

Thanks!
Jody
 

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Where are you measuring the 5V?

You should replace the 2N3055 transistor on the AR board. Get a legit part from arcadepartsandrepair.com, or Digikey. Not Ebay, Aliexpress, Arcadeshop, Amazon, or any other seller that you can't trace back the manufacturer, as there are a lot of fakes out there, and they can damage your game. This is something that should be done for any Atari game with an AR board, as they all have a lot of miles on that part, and when it fails it can damage the game board.
 
Where are you measuring the 5V?

You should replace the 2N3055 transistor on the AR board. Get a legit part from arcadepartsandrepair.com, or Digikey. Not Ebay, Aliexpress, Arcadeshop, Amazon, or any other seller that you can't trace back the manufacturer, as there are a lot of fakes out there, and they can damage your game. This is something that should be done for any Atari game with an AR board, as they all have a lot of miles on that part, and when it fails it can damage the game board.

Um, Atari Football does not use an AR nor an 2N3055. For +5V it uses a LM323. :unsure:


In any case, if the +5V was only 3.5V, it likely would not be booting at all.
 
Low voltage can cause that. As VC suggested, replace the LM323.

Where are you measuring your +5 VDC at?

It could also be a logic issue - lost bits.

Is it consistent (always the same ones?)

I don't see this as a CRT issue. I think it's a game board issue.
 
Low voltage can cause that. As VC suggested, replace the LM323.

Where are you measuring your +5 VDC at?

It could also be a logic issue - lost bits.

Is it consistent (always the same ones?)

I don't see this as a CRT issue. I think it's a game board issue.
I am measuring from the red wire per Mike's arcade pinout text diagrams on there website. The players and left side of the field are always like that yes.
 
Check the shunt resistor around the LM323 too.

If you replace the LM323 with a high current switching regulator you won't need the shunt, as the reg can provide sufficient current without it.

The LM323 is prob dead and all the current is coming through the 4 Ohm resistor.
Thanks man! Really appreciate it
 
If you had to replace the cap on the PSU I'd first verify you're seeing correct unregulated voltage coming off the PSU. Next check the PSU - PCB wiring and the power connector tab on the board itself, probably 2&B. Make sure its not burnt off or heavily tarnished. If it looks at all fried you need to clean and repair it, or in the worst case route around it.

After those two things are verified then replace the LM323 with new,or install a modern switching regulator in its place. These work well: https://ezsbc.shop/products/psu5-lm323k-replacement
 
If you had to replace the cap on the PSU I'd first verify you're seeing correct unregulated voltage coming off the PSU. Next check the PSU - PCB wiring and the power connector tab on the board itself, probably 2&B. Make sure its not burnt off or heavily tarnished. If it looks at all fried you need to clean and repair it, or in the worst case route around it.

After those two things are verified then replace the LM323 with new,or install a modern switching regulator in its place. These work well: https://ezsbc.shop/products/psu5-lm323k-replacement
So I did pull the entire PSU and looked at prior. Looks great on the small board underneath the the big blue and everywhere else. Correct voltage is going to all the other pins per Mike's arcade pinout page
 
Post a pic or video of the 5V measurement, with the DMM, and showing exactly where you are putting the probes.
Sorry it took so long. I had training for a new job and had to travel . This is with the new LM323K installed. Still have same problem unfortunately
 

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Where's the black DMM lead?

Also, according to the schematics, it looks like 5V should be pin K on the edge connector. However what is sometimes not obvious is that Atari skips the letters G, I , O, and Q in the edge connector numbering. So it's easy to be on the wrong pin if you aren't counting correctly.

However there's an easier way to measure the 5V on any board. On most boards, there are 5V and ground traces running next to each row of chips. You can just put your red and black DMM leads there. You can do it on any column, but here's an example:

1759985473465.png
 
Black is at ground pins at the bottom of the row. I will perform it as you say here.Makes it so much easier. If the pot is cranked on the LM323K all the way up and I'm only getting what's on the meter what would be the next logical component to look at?
 
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