Silencing a Sega NAOMI Arcade Board (Cleaning, Damping, Checking)

The Sega NAOMI is a wonderfully versatile, reliable arcade board that, for collectors, is a lot like a more modern Neo Geo MVS. There’s LOADS of games and they are quite readily available.  There’s also loads of them out there so spares are never a problem (at the moment).

Something that *IS* an issue though, by design, is the noise these things make,  When new they are loud but that’s drowned out by their operating environment being loud too.  As they ag, the bearings on the fans start to wear and the holes get clogged with dust they get even louder.  In a home or quiet arcade environment the whine these boards make is horrible.  So with this, and my sanity, in mind I set out to try and minimise the noise through a combination of CLEANING and NON DESTRICTIVE modding.

This is what we have to start with… A perfectly functional but VERY loud NAOMI 1 unit with, judging by the stickers, quite a bit of history.


As we begin: NAOMI, loud, dirty version.

So, these NAOMIs are loud because of one thing. Fan noise.  There are two main fans in a NAOMI board. One on the mainboard and one acting as an exhaust vent sucking air over both sides of the PCB and out of the unit.  This is in the top right of the pictre below.



System board and exhaust fan

These fans both get gunked up over years of use and a fan with gunk can become unbalanced and make more noise.  Its also less efficient at pushing air and, if speed is temp controlled, will therefore spin faster (note that these are 3 pin fans so i DON’T think this is the case for the NAOMI, it’s full speed all the time).  If the heatsink is clogged this can also affect the tone of the fan (backpressure).  So, first up, looking at the mainboard fan.


Honestly, I’ve seen worse but this could use a clean to ensure it doens’t die early.  The main source of noise on Naomi boards is from the exhaust fan (see later).  Time to take the board out of the case.  A few screws, disconnecting a fan cable and it just pulls out.


Main board and filter board out of the case

This leaves us with the underside of the case the the system exhaust fan (shown below).  This think makes nearly all of the noise and it’s all due to a design decision that’s fine for an arcade, less so for home use!


Under tray and system fan

Zooming in a little closer on the fan.  This is a 60mm, high speed unit that is slotted directly on to a plastic vent that is simply placed into a groove on the under tray and then the top cover fits over.  There’s no solid mounting for the vent and no damping or pressure on the fan mounts so, when running, the fan causes a lot of vibration to transfer to the case (ratteling in the groove between the cover and the undertray as well as ratteling on it’s mounting pegs).  On a new fan it’s loud, on an older fan its really loud and has a horrible tone to it.  This is the area I want to do something to in order to damp out this vibration, keeping it quiet and, importantly, keeping the board as stock as possible.


Worlds worst fan mounting solution

Before I did that though I did general maintenance on the rest of the board just to ensure it can keep running for years to come without having to open it up again.  Taking the fan off the mainboardshowed suprisingly little gunk  on the heatsink.  This was cleaned off with cotton buds.


Mainboard HSF

Next, checking around the BIOS on the board to ensure correctly seated and no dirt on the pins.  It was fine so moving on to the BIOS battery. A standard CR2032 cell that holds the settings for the system.  This was replaced with a new cell as I had no idea how old the installed one was.


BIOS and BIOS battery

A quick check on the back of the board….  Clean, no issues I can see.


Underside of mainboard

Time to address the exhaust fan noise.  If the fan is run outside the case then it’s actually quite quiet.  To me this means the bulk of the noise is from the fan vibrating on it’s mounts and in the undertray slot.  When it’s in place the fan is held ‘quite’ tightly in place but it makes physical contact with the top and bottom of the case and is pushed on to it’s hard platsic mounts via compression.  So, first off, help damp the noise made by compression on to the mounting pins.  As below, i’ve added a rubber band to act as a kind of gasket / vibration absorber to (hopefully) stop this vent plate ratteling as much (by both stopping the transfer of vibrations and by ensureing there’s more pressure on the plate stopping it from moving in its mount.


Mk1 rubber gasket

Next, I noted the contact points on the undertray and the top cover and followed the same principals as above by simply placing a rubber band around the center of the fan as this is the area that contacts the case plastic.  NOTE: There isn’t that much clearance when re-assembled and the band has to be medium thick at max.  When all put back together this band should halp damp the top and bottom vibrations.


Simple rubber band damping

Placing everything back together was actually trickier than I thought.  There’s not a lot of tollerance in the mount when slotted in to the case.  I had to twist the front rubber band on its edge to enable everything to fit back together. However, this does seem to have had the benifit of stopping any front – back wobble and also gives more damping surface area for the fan pin mounts.


Damped Fan mounted back in case

Everything was now put back together and the case was given a good clean before hand with cleaning spray and isopropyl aochol (which is great at getting rid of sticker residue.


The board and case are now shiny and looking good. and the internals don’t have anything on them that could cause a failure in the future.  As for the noise.  It is WAY better.  The sound is now akin to a PC CPU fan undrr load.  you can still hear a whoosh of air noise and a slight hum but there’s now iregular vibration, ratteling or anything.  Critically, with this in a cab you can’t hear it in normal gameplay. this was NOT the case before (where you really had to have the volume up high to drown out the fan).


For me, this is a success.  The board is mechanically stock and can be returened to factore clean in minutes but it’s also playable in a home / quiet environment. WIN!

Posted in Arcade, Arcade Hardware, General, Hardware, NAOMI, Teardowns, Troubleshooting | Tagged , , , , , , , , , , , , , | Leave a comment

Sega NAOMI PSU Fix (Capacitors, Capacitors, Capacitors).

WARNING: Dealing with Power supplies can be dangerous. Do not disassemble your own unit without having a basic idea of what you’re doing or dealing with. If unsure, stop!

Recently I’ve been having issues with some games and game boards freezing on me or randomly rebooting.  Initially I thought it was simply the game being odd but then I noticed that they worked better in my 2nd cab.  Not “fine” just less crashy, less of the time.  This raised a flag that it could be something other than the boards sO investigated further.

The  most problametic cab is actually a Sega NAOMI shell without much internal stuff in it (it was stripped when I got it….  Monitor, PSU, JAMMA harness, END).  So, given the crashes were semi random I checked the harness over for breaks and loose joints.. none found.  So, then I needed to  eliminate issues systematically. I started bottom up, working from the AC input.  Isolation transformer/stepdown were reading fine and still solid so next up was the PSU….   This is the standard NAOMI SUN PSU…  It is old.


The Sega/SUN Naomi PSU (JVS)

Getting in to these PSUs is easy as there’s 3 x normal philips screws holding the main metal cover down.  Once out these slide off to reveal the innards.

Step one is to have a visual inspection of the main components in the PSU for signs of obvious damage (burn marks, cracked solder, bad capacitors etc.) As the games are acting oddly at infrequent intervals I’m focusing on the capacitors to start with as they are used to smoothout the power delivery to a board.


What’s that in the bottom right

Almost immediatly you can see something wrong in the bottom right of the PSU.  So lets take a closer look…


Healthy capacitors have flat tops to them.  If they go bad (or start to go bad) you often see a bulge at the top.  Just by looking here and feeling the top of the caps with a finger I can feen three of the bigger caps have a dome and one of those three looks really bad.. At this point I took the PSU PCB out of the bottom metal tray for closer inspection.


On looking closer the capacitor most domed is actually starting to leak electrolyte.  So I figured I’d replace the set of 4 caps here that all have the same value (16V 2200uf).  These are easily obtainable from RS Components or Farnell.

Usually when  you replace one cap you should redo the board. However, in this case, I didn’t have the time to do ALL the caps in the PSU and it was only this set of identicle caps that exhibited any signs of wear.

So, I de soldered the 4 caps and replaced with new ones (about £3 for a pack of 5) and cleaned off the worst of the dust and grime fromt he rest of the PSU to aid heat dissipation etc with some compressed air and a cotton bud + Isopropyl alcohol.


Whacking the board back in the PSU case after a clean up makes it look like it’s a lot newer than it is (manufacture date was 2000).  I tested all 4 of the 2200uf caps I pulled off the board to see how bad they had degraded.  1 was reading 2150uf (i.e. fine). The two with minor bulges were reading about 1800uf (out of the +/-10% tollerance for most caps). The one leaking, however, was registering….. 50uf (so completley gone).


After replacing and placing back in the cab all problem boards are now working flawlessley without crashes or hichups.  This means two things….

  1. I found the root cause in the NAOMI cab.
  2. I probably have to check out the PSU for the BLAST city as it’s older and also starting to show signs of instability in the same way.

Untill the next problem….



Posted in Arcade, Arcade Hardware, Electronics, Repair, Teardowns, Troubleshooting | Tagged , , , , , , , , , , , , , , , , | Leave a comment

So, What’s Inside a Sega ST-V Game Cart (And Differences)

Over the past few months I’ve picked up a few Sega ST-V games.  The ST-V was an arcade system based on the Sega Saturn.  The budget arcade board of it’s time as the main Sega releases were all coming out on Model 2 and Model 3.  The CARTs are quite big and I want to see what’s inside so this post is just about opening and having a look around.


A Stga ST-V cart (Front)

This is the CART in question a very silly Colums like game called Baku Baku Animal. Looks pretty easy to get in to.  Clips on the top and two screws on the back bottom.


Retaining screws

Annoyingly, these are security screws and they are in quite tight.  I know this is done for ‘reasons’ but it’s very annoying.  Happily I have a tool.


Stupid  Security SCrews

This is a 4.3mm ‘Game Bit’ that I bought to open up SNES CARTS.  It fits these security screws perfectly though. Remove the two screws.


4.3mm Game Bit

Once the screws are removed the bottom of the case can be seperated and these two tabs/clips can be pressed to seperate the top of the cart case.  These feel quite delicate though so be careful!


Top retaining clips

Once open we see the front of the cart.  It even fills most of the  space inside the plastic shell.


Front Removed

Taking the PCB out and looking at the front side, everything is really well labelled.  There’s a row of ROMs at the top, filter CAPs in the corners, a couple of ICs (Octal Bus trancievers) and a custom Sega chip at the bottom (guessing this is the program ROM).


ST-V Board Front

The Rear of the CART has space for more ROMs but this is a small game so not used.  Just a row of Octal Bus Trancienvers.  These are used fo 2 way communication (Async) between the ROMS and the controller chip/system.


ST-V Board Back

A close up of the trancievers. All the same part: “3-STATE Octal Bus Transceiver” (guessing the 3 states are send, recieve and off)


IC line

Here’s a close up of the game ROMS.  These are 32Mbit ROMs.  Specific to the game on the cart.


So that’s the inside of a Sega ST-V cart.  I did then take apart another game that I had issues with, Decathlete.  This game was working finemost of the time but had a habbit of freezing at random.  I was worried it was bootleg So I opened it up…


Sega Decathelete

And found this.  From research this is legit and how it came from the factory but the program ROM is a socketed EEPROM (like the ones used for NAOMI BIOS chips (Same label and font).  It’s not super visible in this picture buy 1/4 of this chip was loose in the socket.  Pushing it back down again seems to have solved my issues of freezing.


Socketed Program ROM

The other interesting item on this board is a Sega branded chip the 315-5838.    This is not present on any of the games I have with non socketed Program ROMS (I opened a few others.  I Think this is a comms / decryption chip to stop people simply copying the EEPROM.  I can’t be sure though.


Custom Sega Chip

So that’s the inside of a Sega ST-V cart.  Actually more interesting than I initialy thought and a good example of a mid 90’s budget arcade system.










Posted in Arcade, Games, retro, Sega ST-V, Software, Teardowns | Tagged , , , , , , , , , , , , , , , | Leave a comment

Sammy Atomiswave – System Pickup and Tear Down (95%)

My latest pickup, and something I’ve been on the lookout for a while (as always at not stupid B.I.N Pricing) is an Atomiswave system by Sammy.  This is the cheaper, slightly less powerfull version of the Sega Naomi (i.e. less RAM).  This actually came out AFTER the NAOMI 1 and NAOMI 2 systems just as arcades started going downhill again in the early-mid 2000’s.  Basically a Dreamcast in arcade clothing that runs on JAMMA (with VGA output) so it has great compatibility with old and newer arcade cabs and I’m guessing this was kinda the point given when it was released.


The Sammy Atomiswave System

The system itself is in rather good shape (certainly better shape than the abused NAOMI systems you always see).  Howerver, this has two holes drilled in the side of the system so it looks like someone has done, or tried to do, a stereo Mod at some point.  Will be interesting to see if this is a hack job mod or if any remnents still even exist.


Holes for Stereo RCA jacks

So, time to take it apart and see what we can find inside.  Removing the plastic covers for the expansion ports (used for things like inter cab communications board and the gun controller I.O board) reveals 6 screws that help secure the top plate of the case to the main chassis.  Remove these first.


All the Board Connectors

Now, on the front edge of the case, there’s a retaining screw in between the JAMMA edge connector (totally standard) and the remaining I/O ports on the right.  These are the DIP switches (for setting test mode and 15/31Khz modes), the volume wheel, a connector (CN3) that is for Stereo sound output via an adapter (that I don’t have), the VGA output and a serial port.  It should be noted that, as long as the monitor you’re running through can accept 31Khz via it’s Non-VGA connector you don’t NEED to plug in a VGA cable to use 31Khz mode  It will output 31Khz over the JAMMA edge.


Front I/O

This is a close up of the DIP Switches.  There are a little stranger then most I’ve come across as they ‘seem’ to operate in the opposite direction to how I think they should.  ‘On’ is flicking them DOWN and AWAY from theswitch housing (arrow shown).


DIP Switch Close Up

Flipping the case around reveals one final retaining screw and the FAN exhaust port.  Thankfully this is not as noisy as the NAOMI boards (I know I keep making the comparison but they really are so similar…).  It makes an audible hum, sure, but with game audio simply ‘on’ it’s not really noticable.


Rear Retaining Screw

Turning the case over reveals nothing….  this seems to be the main plate everything inside is mounted to (see the copper Motherboard standoffs visible and some venting holes).


Atomiswave Underside

So, the red top cover will now lift and slide off the rest of the case (up from the back and then slide over the JAMMA edge).  Doing this reveals a mettal Shield protecting the motherboard.  Undo the 5 shown screws and unplug the fan in the top left.  This loosens the plate but it can’t yet be removed due to  the small PCB in the bottom right stopping the plate from coming off.


Metal Shield Under top Cover

Here’s a close up of the part that needs to be removed in order to proceed.  It’s the board containing the volume control and Serial connector.  The serial connector port binding posts (Shown) will unscrew by hand if loosened with a set of pliers (just grip and turn counter-clockwise).


Serial Port Retention

The only thing stopping this board being removed now is this small plasticclip (left side of board).  This holds the board securly in place but, as it’s plastic, could be brittle.  Carefully compress the clip part and you should be able to simply pull the board up and off the plastic post.


Plastic retaining clip

This is the removed board.  A serial port and a variable resistor fo the sound.  The wire connector pulls out easily, there’s no locking clip and it’s keyed so it can’t be put back incorrectly.


Removed board

Now this board is removed we can see the area on the main PCB where the legs of the ‘CN3’ connector push through.  This is the stereo sound connector and shows where a previous owner has attempted to put a stereo RCA mod on to the board.  Clearly they have given up as this is all that remains of the attempt (outside of the holes on the outer case).  The idea would have been to solder wires to the L, R and Ground pins here and then attach them to RCA plugs on the case.  Thankfully, the remnants of this attempt came off really easily.


Botched Audio Mod

The main board has a VGA connector with the same retention screws holding it to the case.  Same as before,  unscrew to continue.


Video out Connector

More screws next with another 4 screws holding the motherboard to the chassis.  The top two are threaded slightly differently so ensure  you know which screw goes where.


Final Motherboard Screws

And now it should be possible to remove the motherboard from the chassis… but it isn’t… it turns out that the design of the Atomiswave includes an integrated heatsink.  But, in this case the CPU and GPU are thermally glued  (via adhesive pads) to a metal heat spreaderitself attached to the chassis.  Great for keeping the costs down and the heat at bay but rubbish for teardown and curious people.  I could technically remove this with a bit of heat and a spludger but i’ve not got any replacement pads and I do want to use the system. So, lets just look around as best we can without removing the board from the chassis.


Enter a captionCPU and GPU thermal pads

The actual design is interesting.  Heat from the GPU and CPU transfer to the metal heat spreader.  This is hollow and attached to the chassis backplate.  It’s also orientated that the exhaust fan pulls air through the gap cooling the system as it goes (direction shownvia arrow). I like this.  Very efficient!


Clever HSF/Air Flow Design

Looking through from the other side we cn see the backup area for the score saving / book keeping battery.  This looks like a standard rechargable Lithium button cell battery.  Happily this has sealed edges so 20 years down the lineit shouldn’t leak and kill the board (unlike every MVS system ever).


Battery Backup Area

Next up to the right is another integrated heat sink which looks like the audio amplifier as it’s connected to the ribbon cable that connects to the variable resistor on the sound control board.


And thats about it for interesting things that can be seen without taking the whole board away from the heatsink.  Now to put it together and go play a game 🙂



Posted in Arcade, Arcade Hardware, Atomiswave, General, Hardware, Teardowns | Tagged , , , , , , , | 2 Comments

Inside Metal Slug 6 (bootleg) Atomiswave Cart

I recently picked up my first Atomoswave board and it came with a copy of Metal slug 6.  Which was nice.  Now, I’m a huge fan of the series but, having played 6 before in the arcades and being a little underwhelmed I’m not super bothered if it’s original or not. This one most certainly isn’t legitimate. Happily, all bootlegs seem to have the same serial number on them so I KNEW this at time of purchase (and the price reflected this).

It works, so the obvious thing to do now is see what’s inside and if it’s as much of a hack up as most of the old Neo Geo MVS boots tended to be (with wires and EPROMs everywhere).


Same Serial Numer, giveaway

Flipping the cart over there’s a very obvious set of 4 x phillips screws to undo that should allow me access to the main PCB.  No ‘warrenty void’ stickers or anything (well, it is a bootleg).


This looks easy

With the metal plate off we get a good view of the underside of the main PCB.  Not very interesting…  A connector, some traces and a small sticker helpfully telling me this is a Metal Slug 6 Board.


Opened up

Taking the board out it does, indeed, look very clean.  I don’t know if the writing on the sticker is the S/N of the bootleg or something else…  Note the holes on the top left and bottom right edges of the PCB (next to the screw holes).  These are guide pins to stop the PCB being inserted in the wrong direction during assembly.  So far, this is a well made bootleg.  I mean, that sticker is even straight!


Clean, well made, straight!

Flipping the board over to reveal the front of the PCB is far more interesting.  ROMS and chips galore!  Again, a very clean layout and quality job. No EPROMs or hacked in wires / resistors, just a regular repro production run.  Taking a closer look at the chips for identification of function and type though reveals…..


Front of the PCB

…Nothing.  Every single chip on the board has had its identification and markings sanded off (neatly) so there is no way of identifying the components used or the supplier (I’m guessing this was the point).  Still, there’s been multiple levels of quality control (or multiple stages of QC stickering) so, again, looks like a quality job!  I’ll have to revisit this a little later when I have a legit cart to compare against so I can work out the chip functions (I’m pretty sure the long one populated in the bank of 4 is the main storage ROM thought).


Sanded off chips

Not much else to say about this cart really.  It plays fine with no graphics wobbles and it doesn’t need any jigelling around in the motherboard to make it work.  A good experiance really.  Obviously it’s not legit so it’s not ‘worth’ anything.  Happily, anyone buying this should be able to spot a boot quickly with the serial numbers all being the same and it being VERY easy to check the ROMs by asking for a ‘legit’ cart to be opened.  You’re not gonna dammange anything by checking.


Posted in Arcade, Atomiswave, Games, Metal Slug, Software, Teardowns | Tagged , , , , , , , , | Leave a comment

Arcade Buttons – Keeping Them Working (Dissassembely and Cleaning)

Arcade Buttons.  You know, the standard convex colourful plastic type that you get on pretty much all candy cabs and modern console ‘fight sticks’.  They are one of the few items in the arcade game hobby that can still be considered a cheap, easily availbale, part.  But, with a standard 2 player control panel having 14 of them (including start) it’s still an expense.

It doesn’t take that long for a button to start to not rebound quickly, stick or even fail to register a press now and again. This is amazingly frustrating when youre going  for a 1CC on whatever is the game of the month.  They fail even quicker if your kids spill a popular branded fizzy drink over the control panel and then not tell you about it for a weekend.

Thankfully, servicing these types of buttons is dead easy, very cheap, and results in the button feeling as if it were new again.  I found this method via a video from Luke Morse (link here) .  This is simple a pictoral version of me doing what he describes in the video in the hope that the more places this information is available, the more people will be able to fix their own gear.

The buttons shown here are standard Sanwa OBSF-30 ‘push in’ buttons most commonly found on japanese candy cabs.  In my case, player 2 side of a Blast City Control panel. Anyway,  to get your buttons working again…

Cleaning Method.

First up, Remove the buttons from the control panel itself.  Disconnect the wiring for the buttons from the pins (They Pull straight up and off).  These are wired in pairs (button x + ground) It doesn’t matter which wire of the pair goes to which pin but you will want to note which pairs got to which button so they can be re attached in the right order. NOTE: I know the pic below are two different pannels… It was easier this way!

Now you can remove the buttons.  These are push fit so simply apply pressure to the two tabseither side of the button (one side shown below) and the button should pop right out of the control panel.


Holding Tab

With the button out we can see the damage and goo thats acumulated and stopping it from working great.  We need to get rid of this  gunk.


Euuuck… Sticky

We’ll need to clean inside and out so, turn the button on its side. and notice the two clips keeping the top of the button in place.  Gently, with not too much pressure, push these tabs free of the main housing and remove the top.  NOTE:  You could snap these off if you push too hard.


Button top release tab

Now, with the cap off we can see theres a good deal of gunk on the cap itself and on the inside of the botton housing.  THis is causing excess friction and messing up the correct opperation.


Gunk Inside



Dirt and gunk on button cap

We have one more thing to remove before cleaning.  The microswitch itself.  This is a black rectangle at the bottom of the housing.  Easy to remove.  Turn the housing upside down, press on the two clips either side of the switch and it should pop right out.


Microswitch Holding Tabs


Empty Casing

Now, to clean the housing and cap, simply use a soft cloth (I use a dishcloth) and some standard cleaning spray (I used kitchen surface cleaner)  Spray the plastics and wipe off any of the dirt.  Careful with the microswitch,  just use a damp cloth on this.


Clean Cap

With the dirt off it would be tempting to just re-assemble and put back together but, to get that super smooth action, grab some bike chain lube (Dry lube recomended) and dab some on to the edges of the button cap.  With a clean cloth work this around the edges of the cap.  Repeat for the inside walls of the housing.  Now, when reassembled, the two pieces of plastic that are likley to touch have lubrication.  I’ve found this to be very hard wearing and lasts a long time.



The Assembled Button

Now assemble in the reverse order by putting the microswitch back in the housing, the cap on the button, the buttons in the pannel and then the wiring back on the pins.  You should have a fully working, highly responsive button.


Buttons Wired (Back how it was)

Now you should go play some games with the responsiveness of a new button 🙂

Posted in Arcade, General, Hardware, Repair, Restoration, Troubleshooting | Tagged , , , , | Leave a comment

Looking Inside A Razion LE (NG:Dev.Team) MVS CART

I recently had a bit of luck by managing to find a copy of Razion for the Neo Geo MVS at a sensible price.  The original manufacturers were doing a reprint of the game (hardly ever happens) so a copy of an already used “LE” version was up for grabs for a sensible, and comparible, price.  So I got it… and now I ant to know what’s inside it….

First run NG:DEV.Team games are a little different to regular MVS carts.  Essentially it’s the same game as the reprint but it comes in a wooden MVS shell.  There’s some included  ‘fluff’ I dont really care about also included in the box (like posters, art work etc.)

Of course, as this is a non standard SNK CART, I figure the insdes are going to be different to the usual SNK MVS boards (should be given it’s boasting 1560 MEGS).  So lets take it apart…  Here’s the CART (LE version).

Razion LE Cart and Board (6)

Spine: Nice Label, Wood Finish

The spine is nice.  The wood shell isn’t two halves that seperate where the label is like ususal MVS games.  Instead, the underside of the shell unscrews leaving the label in pristiene condition.  Good thinking NG:Dev.Team!

Here’s the top of the cart with vent holes and the hologram serial number.

Razion LE Cart and Board (5)

Top of the Shell

This is the underside of the CART.  With the 4 screws holding the wooden plate to the rest of the CART.  They are simple phillips head screws so lets get them out and see what’s underneeth.

Razion LE Cart and Board (4)

Underside: Vents and screws.

Opening up the case and we are greeted with…  A very dull picture.  This doesn’t look that interesting, some 2/3 height PCBs with the interesting stuff facing away from us and, what looks like, some form of connector at the top.  Lets turn them around and see what’s there…

Razion LE Cart and Board (3)

Opened up: the anti-climax shot!

once we’ve extracted the PCBs (snugly fitted in to the case, no wobble!) We see the large chip on the far left being a 512Mbit ROM surrounded by edge trigger chips (don’t know what they do).  The large chip in the center is a NXP microcontroller chip.  These contain USB and memory controller so I’m guessing this is used as the communications bus between the chips onthe right and the ROM boards, RAM and USB header.  Below to the right of that is a Xilinix CPLD (Complex Programable Logic Device) and further over on the top right we have a Spartan FPGA (Field Programmable Gate Array) with more flash rom below.  FPGAs need configuring at startup so I would guess this ROM contains the configuration for the Spartan chip.

Pure speculation here but I would also guess the Spartan chip constitutes the “MCU” you sometimes get a reference to in the game if there’s a error and it needs a reboot.  An FPGA is essentially custom and per task definable so whatever this does, NG:Dev.Team programmed it to do it…  I’ll never know.

Razion LE Cart and Board (2)

PCB 1: The Main Prog board

The next board back is pretty self explanitory in its function but also rather interesting.  It’s theROM board holding all the game asset data.  The top left 2 chips are both 16Mbit NOR ROM chips (I assume for program and sound data?).  The right 2 chips are 512Mbit ROMs which are probabaly the graphics roms.  the row of chips below are a bit of a mystery to me.  Tne Ti branded ones are “Octal edge trigger flip flops” whatever the heck they are…. a wild guess….  paging the ROMs so the MVs can read it?  dunno. If you do, PLEASE comment!

Razion LE Cart and Board (1)

PCB 2: The ROM Board  (or ‘vault’)


The game itself is blooming brilliant.  A very tough, but fair shooter with an excellent soundtrack, great scoring system that rewards risk and a good variety in the levels (although it accelerates from good to great from level 3 onwards).  Linked below are a couple of videos of it running on actual hardware (Sega Blast City, CRT and MVS).

Razion Level 1 Playthrough (Real arcade Hardware, Neo Geo MVS)

Razion Level 2 Playthrough (Real Arcade Hardware, Neo Geo MVS)

Until the next pickup….

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