United Amusements PCE/TG16 JAMMA Unit - Info and pictures

[BlueBMW]

The threads concerning this unit are sparse and scattered, so I decided to start up a single thread detailing everything I know about this unit.  Having just acquired it, I am still learning its ins and outs.

Apparently in the late 80s, the company United Amusements produced these "Turbo Grafx 16" arcade units.  They were designed to be retrofitted into an existing cabinet and allowed an arcade operator to run Turbo Grafx 16 games in an arcade coin op setup.  I'm not sure how many of these units were built, nor do I know how many still exist today.  I speculate that at least 100 maybe even a few thousand of these were produced, though I have no information to back this up.  They dont look to be prototype quality, but on the flip side we don't see too many of them out there, so they must be pretty uncommon.  The serial numbers on the units and Warranty cards dont seem to give much indication on production numbers either.

Ok now about the unit...

/PCEJamma8.jpg

The unit is mounted on plate that can be mounted in an arcade cabinet like any other PCB.  Its not a particularly large unit.  It consists of three main parts, the PC engine, the interface board and the harness.



/pcejamma2.jpg

Its not truly a plug and play JAMMA unit.  Though it uses a JAMMA harness that has been customized for the unit.  In other words, you cant simply plug the unit into a jamma harness of any arcade cabinet and have it work.  The other end of the harness has loose wire ends for coin input, speaker + and -, ground, +12v, +5v and -5v.  It also has two large "AMP" connectors for the player 1 and 2 control panel connections.  This unit has wires for two players, though only player one is functional.  Perhaps they were considering making a two player version later on.  The instruction manual for the unit told of how to install this unit into several different popular cabinets of the time.



/pcejamma7.jpg

I wired the ends of this harness to a JAMMA fingerboard to make it plug and play JAMMA capable.   While not the original intended method of installation, this allows the unit to be installed and uninstalled like any other arcade PCB.  Notice I only wired the 1st player control panel wires in.


/pcejamma1.jpg

The unit uses a standard white PC Engine mainboard.  It has been removed from a shell and mounted with screws and posts onto this unit.  You can tell its an original white PC Engine because of the RF out.  Interestingly though, the unit was advertised as a Turbo Grafx 16 unit.  Apparently the company that distributed this also distributed games for it.  From the pictures I've seen, they look like custom PBCs with ROM chips installed.  I can assume the ROM chips held the game data and the PCBs served to convert US games to Japanese.  I havent tried US games through a converter board yet, so I dont know if the region lock pin is desiabled or not.

The PC engine can be removed and used externally with a power cord, controller and RF unit or IFU.  Inside the unit, three connections are made.  The controller input, the power input, and the expansion port.


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/pcejamma5.jpg

The controller input is a standard mini DIN8 cord that goes to the interface board (more on that later).  It plugs in like a controller would.  The power port has a custom plug that is wired to the JAMMA edge at one of the 12V pins and one of the GND pins.  The other 12V pin has a wire running from it for connection to the cabinet power supply.  Lastly, there is a custom made connector that plugs into the rear expansion port of the PC Engine.  The connector looks to be the same connector as is in an IFU base, Super CDROM, or other accessory that plugs into the expansion port.

From what I can tell, there are the following connections made:

A1: Sound Right
21A: Ground
22B: Reset
22C: Sync
23A: Red
23B: Green
23C: Blue

The Sound Right connection goes to the JAMMA edge of the interface board at the pin labelled "TEST"

The Reset pin is connected to the JAMMA edge at pin "KEY"

The 21A ground and the three video signals are connected to the JAMMA edge pins "V GND" "V-BLU" "V-GRN" and "V-RED"

So basically, the Interface unit inputs the Right channel audio, and the video data in via the JAMMA edge of the interface mainboard.  The audio goes through an amplifier circuit complete with a volume pot and then goes out the JAMMA edge on the +/- speaker connection.   There is some additional sound circuitry that adds sound to the sound output.  Noteably, when you turn the unit on, there is a loud beep sound through the cab speakers, and a chime.  I understand these to be self test sounds.  When a persons credit time reaches 30 seconds remaining, another chime will sound through the cab speakers to tell the player to insert more coins.  

If no more coins are inserted, the system resets and locks out the RUN button.  I'll assume this is why there is a wire connected to the RESET pin on the PC Engine rear interface.


/pcejamma3.jpg

The video enters the unit and is amplified with what looks like a transistor amp setup.  There are trim pots for each color line also.   It is output via a connector that plugs into the interface board.  This connector has the standard arcade monitor input plug on the other end of it.  In the picture above, the video out connection is on the right and the controller input connection is on the left.  Notice there is no red wire on the controller input...

Speaking of the controller input,  I traced back much of the circuit for the control panel connection.  Basically the control panel buttons and joysticks connect to the JAMMA edge of the interface unit.  All the buttons / joystick connections except the start button connect to an NTE74157 chip which is the same chip that is use in TG/PCE controllers to convert 8 inputs into 4 wire output.  The start button takes a different path...  It goes to a switch chip of sorts.  From what I can tell, it is connected or disconnected based on the coin op status of the unit.  The unit uses a timer for gameplay.  When you dont have play time, the start button is disconnected and is thus locked out.  The start button is the RUN button on the TG16/PCE.

Here's a general diagram I drew up of how it connects.  I've cut out the start button's control circuit and connected it directly to the final pin on the NTE74157 chip it ends up at.

/JammaTG16Pad.jpg

It looks like this same setup could be used to connect an arcade style controller to a TG16 / PCE


Here are some scans I made of the interface board:

/TGJamm1.jpg

/TGJamm2.jpg



All in all its a neat setup.  The coin operation stuff is particularly unique!  As far as a unit to use for regular play.... it may not be the best for a few reasons...

One player only... What is the fun of playing on a cabinet if you cant squeeze a second person in there for some two player action!
Mono sound...  In keeping to JAMMA standards, the unit is only setup for mono sound
Turbo?  There does not appear to be any circuitry to support turbo switches on the buttons
Rarity...   These seem to be pretty uncommon units, and they are quite old.  While it seems a robust setup, regular use may shorten its usable life.


Here are a few videos I made of the unit installed in a cab:

Seeing that the connection to the PC Engine is the standard interface... I tried to connect a Supergrafx to the unit.  The onboard power cord didnt fit, so I had to power it separately... but it worked fantastic!

[MotherGunner]

Very very good walkthrough.  Nice job Blue!

[ccovell]

Cool stuff.  The games that came on EPROMs are just standard released US game ROMs with about a dozen bytes at the beginning "NOP"ed out to remove the country lockout check.  The PCE unit has probably not been modified in any way.

[Mishran]

Love to get my hands on one of those. Too bad I'm a dumbass and wouldn't figure out how to install the damn thing anyway. Not to mention I'm lacking one key component... arcade cabinet.

[NecroPhile]

Nice write up, le bleu.  I'm sure glad that you got this thing instead of some rarez collector.

[allyourblood]

Nice write up, le bleu.  I'm sure glad that you got this thing instead of some rarez collector.

Agreed! Also, you did this write-up quick, I must say. Thanks very much for the info. I assumed I'd never get a closer look at this thing, but you've provided a ton of great info and nice, clear photos. Wonderful job!

[csgx1]

Great info with lots of details.  Thanks for sharing.  I was really curious about this setup.  I would love to have a PCE arcade cab someday.

[Chuplayer]

The unit uses a timer for gameplay.

This is the saddest thing you could possibly do in an arcade, short of bad redemption machines.

[T2KFreeker]

The unit uses a timer for gameplay.

This is the saddest thing you could possibly do in an arcade, short of bad redemption machines.

I completely agree. What a bummer.

[esteban]

Splendid article with great pictures.

I missed this thread until this evening—I rely too heavily on the "show recent threads" function on the board.

Anyway, great job.

[DynamiteSJ]

tg16 arcade bios just got dumped into mame.. im sure they get the games working soon if not already

[TheClash603]

Love to get my hands on one of those. Too bad I'm a dumbass and wouldn't figure out how to install the damn thing anyway. Not to mention I'm lacking one key component... arcade cabinet.

Agreed!  This thing looks confusing as hell to me.  I'd love to own some arcade games, but you need to be Mr. Wizard to operate them.