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Nintendo Head On N Arcade Cabinet Recondition

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Posted (edited)

So a few months ago, I bought a Nintendo arcade board on Yahoo Auctions Japan called Head On N. It is a Nintendo counterpart of Head On by Sega. Unfortunately I don't know the story behind this one, but I figure it was just licensed to Nintendo by Sega. The main difference between the two games is that the Nintendo version is meant for a vertically oriented screen where as the Sega one is for a horizontally oriented one. 

Anyway, I got this thing as a converted mess. Someone had converted it to play (according to the listing) Heiankyo Alien, even modding the sound section with a weird hand built daughter card. Unfortunately I could not confirm this though, since all of the ROMs were missing on the back. So basically I had to remove everything and fix all the cut traces (there were plenty on the front and back). This was also used as a parts board at some point as well, as it was missing a lot. I did document the hacks, but I have to do a proper writeup on that.

After populating everything in the sound section, I ran into the issue of ROMs. They use 2708 tri-voltage eproms, which are hard to program with modern hardware. My solution was actually to design a PCB to condense all 8 ROMs into one 2764 ROM, mapped with a 74LS148 encoder IC. It just fits into the original sockets.

From there, it was time to fix the boardset, I was having graphics issues, but fortunately that was a fairly quick fix. You can read more about it on my repair log:

The TLDR is that the chip that serializes graphics was faulty. After getting that replaced, I was able to actually see the game. Head On N, like with other Nintendo arcade boards, does indeed output inverted video. For this I just used a Sanyo 20EZ. It seems to be working just fine.

The next step for me now is to do two things: Make a proper reset circuit and test the audio. Unfortunately I don't have a power supply in my test setup that does the -12V that it requires. I also have to hook up controls so I can actually play it. One down the road thing that I would like to do is modify the ROMs so it can just be used on an upright cabinet. It seems that it is meant to be used in a cocktail table, as it will flip the screen. It's been a fun project so far, I hope to do a custom cabinet for it one day, but that is down the road. I have to just get this board fully working first.

Changing the scope of the thread
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  • 3 weeks later...
Posted (edited)

I actually did get it up and running to test with sounds. I ended up redoing my test harness so that way the power lines hooked up to a separate Happ power supply. Surprisingly I only had to make one correction, I forgot to fix one cut trace. It was involved with the pellet catching sound, which sounded really flat before I fixed the trace. After that, the pellet catching sound was as correct as I could guess. The only one that I might look into is the crashing sound. it almost sounds like it is too high pitch, but it is close enough to where I don't mind. Other than the cut trace, the only other thing I did to the board itself was replace the two onboard potentiometers. I was getting a lot of inconsistencies with adjustment so I just went ahead and replaced them. 

One thing that I did learn, is that on the power connector, there is a reset pin. What's weird is that as long as the coin switch is hooked up, it will reset on it's own as long as that reset pin is tied high on the connector via a pullup resistor. I already had a little PCB designed though that I use for external resets on my test harnesses though.




To explain the circuit, it uses a BD47xx series power supervisory IC. How it works is it monitors the 5V rail, once it crosses the set threshold, I used a BD4746 so 4.6V, it pulls the reset line low (pulled up via pullup resistor). Some games, like space invaders use an inverted version of this, hence the second active high RESET signal. Head On N uses the first active low /RESET signal on this board.

By adding this reset circuit to my harness, it will be a more properly set up harness. For now, I just have an old junk microswitch hooked up as it is required for the game to operate correctly as it uses all three pins on the microswitch. 



At this point, the PCB deconversion is complete. It was a cool project that I hope to put into a cabinet one day.

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Here are my notes from the deconversion, I had a rough time finding pinouts and stuff online, so I figure I can post it here. Unfortunately I don't remember the buttons for actual gameplay, I just kind of poked around with a ground wire to test it. I apologize, but it is a bit disorganized as this was just transcribed from my handwritten notes.

CPU Board - P1 Power

  1. GND
  2. GND
  3. +12V
  4. +12V
  5. +5V
  6. +5V
  7. Unused
  8. 12V
  9. Coin Counter / Lockout coil Voltage
  10. Counter/Lockout return Voltage
  11.  Active Low Reset

CPU Board - P2 Sound

  1. Sound out
  2. GND (Sound Return)
  3. Unused
  4. Unused

CPU Board - P3 Sub Controls

  1. -
  2. -
  3. -
  4. -
  5. -
  6. GND
  7. GND
  8. GND
  9. GND
  10. GND

CPU Board - P4 Main Controls


  1. -
  2. -
  3. -
  4. -
  5. -
  6. 1P Start
  7. 2P Start
  8. GND
  9. GND
  10. GND
  11. GND
  12. GND
  13. GND
  14. GND
  15. GND

CPU Board - P5 Coin Blocker

  1. Coil Voltage
  2. Unused
  3. Coil Return

CPU Board - P6 Coin Counter

  1. Coil Voltage
  2. Coil Return

CPU Board - P7 Coin Switch

  1. Coin Switch Common
  2. Coin Switch Normally Closed
  3. Coin Switch Normally Open

Video Board - P1 Video Out (Inverted Video)

  1. Green
  2. Red
  3. Blue
  4. GND
  5. GND
  6. Negative Composite Sync

Video Board - P2 Power In

  1. GND
  2. GND
  3. GND
  4. +12V
  5. +12V
  6. +5V
  7. +5V
  8. -5V


Mod Notes

These were the mods that were done to the board.

  • Stacked Chip at E4 - 74175
    1. Connected to lower chip
    2. Unconnected/Cut
    3. Unconnected/Cut
    4. Unconnected/Cut
    5. Connected to Lower chip
    6. Floating
    7. Connected to daughtercard
    8. GND
    9. F4 Pin 9
    10. R74, E4 Pin 7 Side
    11. Unconnected/Cut
    12. F5 Pin 17
    13. F5 Pin 8
    14. Unconnected/Cut
    15. Connected to daughtercard
    16. +5V
  • 5A - LM1458 removed
  • 5C pin 2 - Remove pin from original circuit, removed pin to +5V
  • R42, R43, R50, R40, R41, R48, R49, R65, R21, R26, R15, R55, R66, R83, R77, R7, R8, R9 - 100k resistor removed (perhaps parts board removal)
  • C32, C31, C18, C24, C25, C78 removed
  • D1 - Removed (probably because parts board, replaced with 1N4007)
  • C78 to R61 Cut
  • C44 2.2uF ->
  • 3A - LM741 Op Amp removed (probably because parts board)
  • 4A - LM1458 Op Amp removed (probably because parts board)
  • 1C pin 10 -> diode - 3B - Pin 4
  • 1C pin 8 cut from circuit
  • 3B-2 Pin 4, cut from circuit
  • Trace from R67 to C43 cut
  • Trace from R67 to 2C cut
  • R67 -> 2C pin 15 added
  • C40 capacitor replaced with 2.2uF 35V tantalum connected to 100k
  • R56, R79, R89, R34 10k resistor removed
  • R80 -> slid over to 1C pin 8
  • R33 -> 5E pin 15 cut, jumped to pin 14
  • P6 pin 10 -> Cut, jumped to RM1 pin 7
  • C23 10uF/25V tantalum -> .47uF electrolytic
  • P2 pin 1 cut, 10uF tantalum added inbetween
  • C26 -> Chagned to .0022uF mylar
  • P4 pin 13 cut, jumped to RM2 pin 6
  • P4 pin 15 cut, jumped to RM2 pin 8
  • P3 pin 5 cut, jumped to 1G pin 5
  • P4 pin 5 cut, jumped to RM2 pin 7
  • P4 pin 6 cut, jumped to 2F pin 15
  • P4 pin 7 cut, jumped to 1G pin 3
  • C48 .047uF mylar -> 10uF 35V tantalum
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Posted (edited)

The schematic for the external soundboard, I had to make some guesses because it was damaged it seems, but this is my best guess. I attached it as a screenshot and as a PDF because VGS compresses this.

Head On N Mod Board.pdfimage.png.eafaef2011507b4699c331d367154b94.png

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  • The title was changed to Nintendo Head On N PCB deconversion and Cabinet Work

So I decided to change the scope of this thread. I am doing a full Head On N upright cabinet. Since fixing up the PCB, I aquired a Nintendo cabinet that had been converted (and LCD'd) to a 10-yard fight themed multicade (as well as a punchout project). It was originally a Donkey Kong cabinet, so it's time to turn it into Head On N with good ole fashioned original hardware (for the most part).



The first step towards the cabinet was figuring out the power supply situation. The problem is that Head On N uses a power supply with -12V and -5V. Many power supplies used in arcade cabinets had one of those but not the other. To complicate things more, the original also provided a reset signal. I took a different approach to this one. I decided to make a proper adapter board that just fits in a modern switching power supply. For this I used a Meanwell RT-125B mounted to a Donkey Kong power supply block (which was missing it's original supply). The 125B is very reliable and high quality so it was a no-brainer for me to use. It provides a -12V line which I tap from and make -5V using a 7905 regulator. The reset signal is made using a BD47xx series power monitor IC. It should work just fine, but I haven't assembled it yet. I do know that my design fits the power supply though.


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  • 2 weeks later...

I brought the cabinet home yesterday. So tonight I started the de-greening process. For this task I am using Citrusstrip, it is harsh enough to the green paint but isn't effecting the really sturdy blue gelcoat that Nintendo used back in the day. After 20-30ish minutes, the green was peeling right off. Residue was coming off easily with simple green cleaner after.

It cleaned up really nicely.


So far, this is just one side. I have a lot to do tomorrow, but I am hoping to be able to strip the other side and the front tomorrow. The front is going to be a bit tricky, but that is tomorrow me's problem.

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The cabinet is now for the most part de-greened. It cleaned up a lot better than I thought it would and the cabinet is really nice.


The parts I need to build the harness are now on order, so I will be able to hopefully build it that this week. I also have a monitor on the bench that needs a lot of work, that will be a separate post. I was able to mount the game board, so that turned out nice. 



I wanted to work on and mount the coin door, but the screws that were mounting it when I got it were not correct (phillips head screws vs metric carriage bolts). The worst part is that I know I have these carriage bolts, but they are in the coin bucket of DK Jr which I took to storage. So I will have to grab them later. I was able, however, to mount new coin mechs since the ones that were on there were just spray painted face plates. These are not Asahi mechs like the original, but they are clones of the old Coin Co Asahi-clone mechs (yes, clone of a clone) that were found on old gremlin cabinets (like head on). I have a goal to have every one of my large Nintendo coin doors to be in a different configuration with the return setup, return catch, and how many mechs per machine; so this helps. 


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  • The title was changed to Nintendo Head On N Arcade Cabinet Recondition

Well I finally had time to assemble my power board and build the power wiring harness. It worked out pretty well, so I finally had this game booting for the first time in the cabinet. The only thing I had to do was add a cord cap for the light fixture because someone cut the end off.




So here's what's left:

  • Upright cabinet romset
  • Controls wiring harness
  • Art package needs to be made
  • Finish ground wiring (almost done)
  • Monitor adjustments

One thing that I am a bit agitated about with my power setup, was that I decided to use the RT-125B, which was great because it has a 5V, 12V, and -12V. I used the -12V rail to make a -5V rail using a 7905 regulator. However, meanwell makes ANOTHER power supply that also includes the -5V rail built in: RQ-125B. So I might switch to that and make a new power board.

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Coins are dumb, or at least the way they are handled on this board. So the way it has to work, is there are three wires that hook up to a coin switch: Normally Open (N.O.), Normally Closed (N.C.), and Common. Head On N uses all three, where as most other games later on used just N.O. and Common. So I have a coin door harness for a Donkey Kong machine, so ideally I would like to use that, so I have to adapt it.

Well this morning, I had a thought: what if I use a mosfet to drive N.C.? The whole idea is that the coin signals are pulled high via weak pullup resistors. When the switch is flicked N.C. becomes high and N.O. goes low. That said, if I add the mosfet, the weak pullup will be enabling the driving of the mosfet. When the coin switch gets flicked the mosfet is no longer engaged so the signal goes back high.


So to test I just soldered the transistor to the back of the board. It worked as it should so I will make a cleaner implementation as I had to bend the transistor legs as the pinout wasn't ideal. I'll probably make a little board so I can use an SMD component, making the mod better hidden.


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Rigged up a control panel harness and modded the roms to be single player only. Reason I chose single player only is because I am trying to figure out how to make two player mode work without flipping the screen. Head On N is meant to be in a cocktail table, unfortunately there is no dip switch for setting it to upright from what I can figure out.


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