Food Fight NVRAM fails

Aniraf

Member

Donor 2016-2017
Joined
Sep 25, 2010
Messages
351
Reaction score
3
Location
Phoenix, Arizona
I just got this food fight machine where I seriously couldn't have any more problems within the first two days of ownership :(.

Everything was working fine (after I fixed the joystick) then I received a NVRAM "time and statistics" error. I went into the self test mode and did a full factory reset then everything worked just fine. Now one day later, I'm getting an NVRAM "high scores" failure. I tried resetting again, but that didn't work.

Is the NVRAM flakey in these old machines? Is this something that is replaceable? My only thought is that the ram may be soldered to the mainboard, I'm really not sure how it is configured and the manual isn't helping too much.

Lastly, is this something I could be causing by cycling the power off everytime I'm done with the machine? Is there a recommend way to gracefully shut down the machines beyond toggling the switch on the back?

Any information you guys have would be great!
 
It's an X2212 NVRAM chip located at 9N. It's a 256 x 4bit chip that runs off a single 5v supply.

If it's socketed, clean the pins and reseat it. If that's not it then replace it.

If it's not socketed then replace it.
 
So the ram is socketed like a modern computer? I'm kind of scared to pull the board out of the emi shield. Knowing my luck I'll mess something up. I've worked on computers my whole life, but I'm a little timid when it comes to electronics from 1982. Are they as durable as current pcbs and computer parts? If I pull the board out and give it a compressed air cleaning plus tinker with the ram, do I risk failure?
 
The NVRam on Food Fight is not socketed. It is soldered onto the board.

Yeah, they can go flakey. If your voltage is a bit low, this could be the cause of the problem.

Also, I think you can bypass the NVRam failure to play the game. You just have to calibrate the joystick every time you turn it on. :mad:
 
MikeyDee! NICE!! Your comment about the voltage being a bit low made me think about something...I just plugged it into a power-strip. Sure enough, I plugged it back into the wall and it worked perfectly!

Thank you so much!

What's the shelf life on these parts? I'm just wondering how long until I have to cry over a broken board :).
 
I don't think that Food Fight boards have any glaring design flaws, except the NVRam :D)

Mine was bad, so I took out the old chip and put a socket in it's place. Like Mark said, you can still find the X2212's.
 
That's good to know, I'll keep an eye out for some extra chips just in case something dies.

Thanks for the great info, you guys Rock!
 
Turning multiple games on with a power strip will cause issues like this. Some games are more sensitive than others, qbert is one of them.
 
I actually think this happens every time I power it on while it is plugged into an outlet with a powered up light fixture. I know this sounds insane, but it seems that the small drop in power is just enough for it to fail the initial nvram check.
 
7 years later

It's been 7 years and I still battle this silly nvram issue. I desperately want my food fight game to save high scores, yet I can't reliably figure out what is causing it to fail.

Simply moving the machine to new power outlets could light up the nvram for 25 power cycles, then it randomly stops working and will not work again until I move the machine. Or it may not work.

In 7 years, I've learned a lot more about these machines, but clearly not enough. The only thought I have left is that the board has some kind of issue (the test points report the correct voltage) or the AR2 is somehow messed up.

This thing makes me crazy! I've replaced the nvram chip. I've rebuilt the whole power supply. I've repinned the edge connector.
 
well, "where" you checked your AR2 voltages will make a difference. if you checked directly at the power supply, that doesn't necessarily mean that's the voltage that's reaching the chips on the board. a dirty edge connector will drop it. a burned up edge connector will be even worse. I've seen this NVRAM error on the Food Fight at one of the local arcades -- incidentally the game was freezing up and I increased the voltage slightly (I run voltages very conservative -- just enough to reliably operate the game) .. I don't think the error's come back since then.

with Atari games the most accurate way to read voltage is at the Sense pins in the 9 pin power plug at the AR2. you'll need to dig up a pinout, I can't remember the pins anymore (and I did a few of these last week!)

if your edge connector is burned up all hope is not lost. you can tunnel the power into the board directly at the +5 and ground points on chips on the board. if you use existing AR2 wiring you should have 2 pairs of +5 and grounds -- I would tap them in at opposite ends of the board.

since you will then have a direct shot into the board instead of relying on the harness/edge medium to deliver power, it will theoretically disable Sense. Sense if you didn't know is Atari's method of balancing the voltage to the board. if it "senses" a voltage sag, the AR2 will automatically raise the +5 output to compensate. the problem with this is a) the games are like 35 years old now and b) a dirty edge connector will inhibit power from getting through and it will turn into an exponential rise in current until the edge connector finally burns up.

this happened on the Dig Dug at work. I soldered wires into chips on the board and added a molex plug, and then cut the existing power wires deep off the harness and connected them that way. if I can get to the game tomorrow I can provide visual aids. or you can read my PSU guide to see the pinout of chips and how to clean the edge connector with an eraser.

good luck
 
This is fantastic information! Thank you! I figured I should probably at least report what I've tested in hopes that I can actually fix this!

I originally tested the power brick voltages using this image that another KLOV member gave me:

y3miKszKj4zohRx6iyjU7D6DvjBev4eekFxTKj4YaVrC-pYiVwG7MhJ6KHTYtDl0B8GxbnBPWJWg47Y_nMlVHQc0SzO_kN2Y-4DJiiRm_Ffgy8oKobXSGYSWFrwx57OQNAK7n77w-itc5mZidOLNHRwgTQ9BxlKY9AfpJbBdBjoIws


I came out with:
J5:
- 15+13 = 64.4 VAC
- 12+10 = 64.3 VAC
- 9+8 = 6.3 VAC
- 5+3, 5+2, 5+1 = 15.3 VDC
- 6+7 = 38 VAC

J4: 1+3 = 121.3 VAC

I just tested the +5 VAC at the board and saw that it was around 4.9, so I adjusted the pot on the AR2, and brought it up to about 5.04, but that seems to be the max it's going to go.

I've also considered putting new pins on the edge connector. My FoodFight board has the EMI shield. I'm curious if I can test by skipping that entirely and putting the edge connector directly on the board.

I feel like this has to be a super small voltage issue because of the way that these Atari games write to the NVRAM. I would assume if it were off even a small amount, the saving could fail. Granted on my end, I'm wondering if it's more on the startup where it's failing.
 
I absolutely want to go to one of these, but I'm actually having my annual gaming party on that same day. :(

If you would, please keep me in the loop. I'll gladly attend the next one!

Now if someone wants to head out to my house before the party, I would gladly do that :p. Last year I had one of the co-owners of Starfighters arcade over to the house because I was having a monitor freak out with a Centipede machine I had just purchased. He was super nice, and helped me get it fired up for the party :).
 
I absolutely want to go to one of these, but I'm actually having my annual gaming party on that same day. :(

If you would, please keep me in the loop. I'll gladly attend the next one!

Now if someone wants to head out to my house before the party, I would gladly do that :p. Last year I had one of the co-owners of Starfighters arcade over to the house because I was having a monitor freak out with a Centipede machine I had just purchased. He was super nice, and helped me get it fired up for the party :).

Well if you head over to the forums and sign up there, I announce all the parties there. We typically have one a month during the cool months of the year except for Nov/Dec because of the holidays...
 
This is fantastic information! Thank you! I figured I should probably at least report what I've tested in hopes that I can actually fix this!

I originally tested the power brick voltages using this image that another KLOV member gave me:

y3miKszKj4zohRx6iyjU7D6DvjBev4eekFxTKj4YaVrC-pYiVwG7MhJ6KHTYtDl0B8GxbnBPWJWg47Y_nMlVHQc0SzO_kN2Y-4DJiiRm_Ffgy8oKobXSGYSWFrwx57OQNAK7n77w-itc5mZidOLNHRwgTQ9BxlKY9AfpJbBdBjoIws


I came out with:
J5:
- 15+13 = 64.4 VAC
- 12+10 = 64.3 VAC
- 9+8 = 6.3 VAC
- 5+3, 5+2, 5+1 = 15.3 VDC
- 6+7 = 38 VAC

J4: 1+3 = 121.3 VAC

I just tested the +5 VAC at the board and saw that it was around 4.9, so I adjusted the pot on the AR2, and brought it up to about 5.04, but that seems to be the max it's going to go.

I've also considered putting new pins on the edge connector. My FoodFight board has the EMI shield. I'm curious if I can test by skipping that entirely and putting the edge connector directly on the board.

I feel like this has to be a super small voltage issue because of the way that these Atari games write to the NVRAM. I would assume if it were off even a small amount, the saving could fail. Granted on my end, I'm wondering if it's more on the startup where it's failing.

very rarely do you see Atari games with the filter boards intact in the field.

I should expand on this a little bit more. your voltage topping out at 5.04 is probably because the caps are original. I suggested measuring at the Sense pins on the DC output on the AR2 -- the AC voltages should never be off because transformers almost never fail.

the 10.3VAC passes through a bridge rectifier in the brick, then the Big Blue filter cap, then the AR2 receives that voltage. the 10.3V is passed through the 2N3055 bottlecap transistor and then comes out +5. an easy test to perform on Atari games is across the +5 and ground rails measuring for AC. if you have a significant enough AC voltage across those, your Big Blue needs to be replaced. all the real heavy lifting is handled inside the brick itself, not the AR2.

the way Sense works is you have +5 and ground coming off the AR2 to power the game board logic. those voltages are then returned back to the power supply, observing any voltage loss between the AR2 and the game board. if the AR2 "senses" that this voltage isn't high enough it will increase the +5 output on its own. I'm guessing the voltage regulator itself controls this, I haven't figured that part out yet.

Sense is kind of a scary feature, always ensure that the edge connector on the board is clean, and do away with the filter board, it's another mode of power loss. it's just about the exact same thing as measuring voltages directly at the chips, which is what you really want to know.
 
I've replaced the big blue cap on this power supply. I've also done the sense mod to the board.

How do I measure the sense pins on the AR2?
 
Okay, so this is strange. Right before my party, the machine started freaking out and just showed colored triangles on the screen. I tested the voltage at the board, and it had dropped to 4.3. The AR2 pot was in the max voltage configuration. So, I swapped my AR2 with another one I have, and the new one fixed the game, and puts out plenty of voltage, however this didn't fix the NVRAM at all :(.

I had assumed that my problem was related to incorrect voltages at the board, but based on this test I would say that isn't the issue at all?
 
Back
Top Bottom