Need guidance on what the problem might be

Saiyenbreutus

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Sorry if this will be a long post but could really use some help!

I just purchased a Johnny Nero action hero game off Craigslist. When I went to test it, the picture came on and the game played but it had some things wrong with it. The sound didn't work, and every time it turned on you had to calibrate the guns. I gave a $100 for it so I figured it was well worth it!

Well when I got it home I plugged it in and it was still doing the same thing. But I noticed at the top of the screen that it had some horizontal lines near the top, I played with the v-hold and h-hold a bit and it affected them, but they wouldn't come out. Figured monitor might have a few problems that a new chassis would fix. So I thought I'd start by tackeling the guns needing calibrating every start up. I assumed the cmos battery needed replaced. So I shut the unit off, took out the battery and popped a brand new one in. And now I get nothing... the screen stays black when I power it up. I know it's possible that in that moment the screen went completely, but I will say that the monitor does power up, I'm getting glow in the neck and you can hear it power up, also if I disconnect the video cables from the Jamma while running it flickers colors on the screen. So I was looking on the board and I didn't notice at first, but under the cmos battery it says replace only while unit is powered on. I replaced the battery with unit off. Did I some how screw this board up replacing a battery with it off?

Also I'm not sure if it matters but the manual says the HD led on the pcb should be on and it Is not on now, don't know if it would light before this happened. But I do hear the hard drive spinning up. I've checked voltages at the Jamma harness, I am getting +5.00 -4.54 +11.47. And The three voltage lights are on. I've also checked voltage at the hard drive connector and see +5.00 +11.46

I plan on posting in the monitor section to see if someone can tell me what chassis I need to buy rebuilt. I figure it's worth that. But maybe not if I bricked the board somehow.

Any thoughts or a place to start would help a lot, I can get pictures of anything you need. Is my monitor just out or is there a deeper problem...
 
Did you try putting the old battery back in?

I tested both batteries the new one was 3.3 volts and the old one was 2.8 volts. But I did actually try putting the old one back in at one point and did it while the unit was on hoping for some real miracle lol
 
I replaced the battery with unit off. Did I some how screw this board up replacing a battery with it off?
Yes, you most likely killed it. I remember seeing a similar post a while back. I'm guessing it says to replace it with the game on for a reason... probably because it stores some required data in battery backed RAM to prevent piracy (similar to suicide batteries used on other games).

There's some info in the comments of the MAME driver: https://github.com/mamedev/mame/blob/master/src/mame/drivers/vp101.cpp ... you could try holding Start 1 while turning it on and see if anything comes up (it says it should show the POST).

DogP
 
Have you checked the power supply voltage? a service bulletin is posted regarding the 5v. https://www.arcade-museum.com/manuals-videogames/J/Johnny_Nero_Action_Hero_Tech_Bulletin.pdf

Yeah I saw the service bulletin, as long as I'm checking it correctly (bolt meter with Jamma harness I plugged and then checking directly on those inputs. I'm showing +5.00 on the nose after adjustment and -4.54 as well as +11.47. But while it was working it was at +5.08 I adjusted after the battery change to see if it made any difference when it wouldn't kick on.
 
Yes, you most likely killed it. I remember seeing a similar post a while back. I'm guessing it says to replace it with the game on for a reason... probably because it stores some required data in battery backed RAM to prevent piracy (similar to suicide batteries used on other games).

There's some info in the comments of the MAME driver: https://github.com/mamedev/mame/blob/master/src/mame/drivers/vp101.cpp ... you could try holding Start 1 while turning it on and see if anything comes up (it says it should show the POST).

DogP

This is exactly what I was afraid of... I have heard of games using a "suicide battery" never ran into one and it never crossed my mind. So depressed... I'll hold start 1 and see if that gives me anything, I'll update. Seems so crazy to me and just such a bummer.
 
This is exactly what I was afraid of... I have heard of games using a "suicide battery" never ran into one and it never crossed my mind. So depressed... I'll hold start 1 and see if that gives me anything, I'll update. Seems so crazy to me and just such a bummer.

Yeah, unfortunately that's quite likely. Most of the hardware is implemented in a Virtex-II FPGA. The battery may have been used to retain its configuration data or to hold the bitstream decryption key. If that's the case, then the PCB is buggered unless the data can be reprogrammed via JTAG or similar. I'm assuming there's a programming header somewhere; can you take some close-ups of the PCB?
 
One other alternative is try to starting the game up with *no* battery installed. Sometimes putting the battery in while the machine is off and then trying to start it up will cause the PCB to think the null dataset is real and will cause a crash on boot. If you get the game to start up without the battery then go ahead and install the new battery while the machine is on.
 
Here is a picture of the board close up, looks like I'll have to post each picture separate because of size.

I tried starting it up with the start 1 button pressed, the start 2 button pressed and with the test button pressed. None of those seemed to make a difference. I will go remove the battery right now and try to start it that way!
 

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Thank you Phil! And all of you for helping me look into this.

I tried to start it with no battery in it and no change. Out the battery back in while it was on and then restarted again with no change. Used the original battery again for giggles!
 
For future reference, the battery that powers the RTC and CMOS RAM is inside the yellow SNAPHAT package.

There's a slim chance I might be able to obtain the data used to program the FPGA but I think you're best off finding another PCB at this point...
 
For future reference, the battery that powers the RTC and CMOS RAM is inside the yellow SNAPHAT package.

There's a slim chance I might be able to obtain the data used to program the FPGA but I think you're best off finding another PCB at this point...

Thank you very much for trying. I appreciate it :) let me know if you find something, for what it's worth how do you change the battery in the yellow snaphat package?
 
Thank you very much for trying. I appreciate it :) let me know if you find something, for what it's worth how do you change the battery in the yellow snaphat package?

I don't think these modules are designed to be opened; you'd likely need to buy another. The module is mounted on top of an IC and is designed to be removed (see: https://www.glaver.org/blog/?p=170)
 
Was such a terrible mistake on my part thinking I knew what I was doing :shakinghead:

Even worse I can only find one new pcb board and it's $400 on eBay... so bummed. Any one have any thoughts on where I can find one of these boards cheaper? I don't just need a new hard drive of it do I? I need the whole pcb board right?
 
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