So, you have sucessfully combined the pile of parts into three PCB’s, two cables and a piece of wire (or you cheated and bought it ready assembled) – now you need to know how to fit it onto your galaxian PCB.
To start, the PCB you fit the multigame to must be a working galaxian, original or bootleg, single PCB or cocktail PCB’s. The multigame will not work on a board that is setup to run Moon Cresta or Scramble as these have different memory maps. These boards can usually be converted back to a galaxian memory map, for information on this see the troubleshooting information.
If the PCB does not work, the chances are that it will not work with the multigame either. The only error that the multigame would fix is if the rom daughterboard was missing or broken, since that part is no longer used.
Start by removing all of the unwanted parts from the galaxian PCB, these include any program roms, whether they be mounted directly on the PCB, or mounted in a daughterboard (7F/7J and 7K), the colour prom (6L), the two graphics roms(or the graphics rom daughterboard (1L and 1J) and the Z80 (8B) – I’ve marked the areas on the board so you know where to look.
If any of these chips are soldered directly to the board, you will have to remove them and place a socket in the location instead. It may be worth doing this before removing everything else so that you can test the board before commencing the installation. (the only chip that may not be socketed is the colour prom – I have never seen any of the other chips involved soldered direct to the PCB)
Check the pictures to see what version of the PCB you have, there are currently two you could have. The main difference is the connectors used, V1 used 6 pins in line, V2 used 2 x 3 pins and has space for a battery.
Place the Z80 that you removed from the main PCB into the socket on the multigame CPU board.
Insert the CPU board into the socket that you removed the Z80 from. (8B) Ensure that the pins are all in the correct place (not overhanging either end) and then push tightly home. If the socket has very small holes and the pins will not fit, then you may need to place another 40 pin socket into the socket on the galaxian PCB and plug the multigame into that instead.
Now insert the colour PCB into the colour prom socket (6L). The notch should face the same way as the other chips on the board.
Now you need to do the one bit of soldering. You need to attach a wire from the single pin on the CPU board to a pin of an IC on the galaxian PCB. The IC to solder it to is the 74157 at 3J. We need to solder the end of the wire to pin 1 (see photo). This is fairly easy because it is a corner pin, which gives a little more room to work in.
Once this is done, solder the other end to the c-rom pin on the multigame CPU board.
Now we need to connect the other boards. We’ll start by running a cable from J3 to the graphics board. Pin 1 on J3 (nearest to L1/L2) should be the same orientation as the connector on the graphics PCB, pin 1 being the nearest pin. Connect the graphics rom end first as there is less room and the plug will only fit one way, then connect the other end to the CPU board ensuring pin 1 is correct.
The second cable goes from J1 on the CPU board, to the 6 pin connector on the colour prom board. However, this time, one the colour PCB, pin 1 is the pin at the notched end. Plus the cable onto this connector first, and then connect to J1 on the CPU board ensuring that pin 1 is correct.
Now we need to connect the other boards. Run one cable from the connector labelled ‘colour’ on the CPU board to the colour board (single eprom), and one cable from the connector labelled ‘Graphic’ on the CPU board to the graphics rom board (two eproms)
Tidy up the wiring using cable ties or similar, that helps to ensure you don’t catch it on something when you move the board around.
Edge Connector (DC version)
(Letters are taken from silk print on Namco PCB : Z is top of board, nearest the dip switches)
|Speaker –||Speaker +|
|Video Blue||Video Sync|
|Video Red||Video Green|
|Player 1 Fire 2||Player 2 Down|
|Player 2 Left||Player 2 Right|
|Player 1 Fire||Player 2 Fire|
|Player 1 Left||Player 1 Right|
|Start 1||L||Start 2|
|Player 1 Down||Player 1 Up|
|Coin 1||Player 2 Up|
|Coin Lockout||Coin Counter|
|1 Play Lamp||2 Play Lamp|
|7v Out||E||7v Out|
* I have seen several bootlegs where speaker- is not connected to anything. In this case you will need to wire your cabinets speaker- cable to ground.
The more observant may have noticed that Player 1 has two fire buttons, but player 2 only has the one. That is because we have used all of the inputs normally available on a galaxian PCB.
To allow for the two extra buttons possible (Player 2 – Fire 2 and Menu) we need to re-use two of the dip switches.
The best way to hook these up to the edge connector depends upon your exact usage of the board. If you have a DC converted board, you may be able to re-use one or more of the two 7v out connectors. If you have an AC board then the easiest to use is probably the coin lockout and the coin counter lines.
Firstly, check that the two edge connectors you wish to use are not connected to anything – They normally connect to a pair of diodes (D9 and D10) and from there to pins on 10L (which pins seems to vary from board to board) – simply break the track to the edge connector that you wish to use, and add a wire from the track between the edge and the break to the following pins
The pins needed are :- Player 2 – Button 2 : Pin 12 on IC 9C, Menu Button : Pin 14 on IC 9C. (remember for these to work properly, the first two dipswitches (nearest the CPU) have to be OFF)