1/6/2012 - write up version 1.0
2/3/2012 - write up version 1.1 (PCB daughterboard option)
12/18/2012 - write up version 2.0 (removed old options, and used extra socket instead)
7/29/2015 - write up version 3.0 (added plug and play solution)

For Centipede troubleshooting info please see the centipede fix page
For Centipede RAM layout information please see here

This is a write up of a hack to replace the 4 2516 game EPROMs with a single 2764 EPROM, this hack is designed in a way that makes use of the extra un-populated ROM socket on the centipede board. By hacking this unused ROM socket you can switch between the single ROM version or the regular version without having to "un-hack" the board.

Disclaimers

I take no responsbility if you try this hack and you or the hack end up damaging your board, your machine or any type of damage to your property or yourself. So if you try this, you do it at your own risk. Do not sue me or complain if your try them and your board breaks or it causes some type of damage to you or your property.. in fact I wouldn't recommend hacking any board unless you have a reason to (like trying to fix a board that might be damaged in the ROM area, or if you don't have working 2516 EPROMs to replace broken ones with)

The following hacks are described

• Hack 1: Replace 4 2516 (2K) game EPROMS with a single 2764 (8K) EPROM

Hack 1: Replace 4 2516 (2K) game EPROMS with a single 2764 (8K) EPROM

What you will need for this hack	1 2764 EPROM chip about 6 inches of high gauge (thin) jumper wire 1 24 pin (.6") IC sockets 1 28 pin (.6") IC sockets a solder iron and solder a solder sucker a wire stripper and crimp tool A EPROM programmer (or someone to program your 2764 EPROM) A Centipede version -01 PCB board
The image below shows the pinouts and the numbering of the 2764 chip (and socket). In the instructions below we will refer to the pin number shown in the diagram
Remove the 4 2516 EPROMS from your game board (In slots ROM 0, ROM 1, ROM 2, ROM 3)
Get 1 empty 24 pin (.600) sockets. Get 1 empty 28 pin (.600) sockets.
Notice that the centipede board has an un-populated socket area at position K1
De-solder the socket via's and solder in a 24 pin socket
Flip the board over Cut the 2 traces in the PCB as shown Solder in the 2 jumpers wires as shown
Flip the board over Take the 28 pin socket, solder together (use some jumper wires) the top 3 pins on the right side (pin 26,27, 28) Cut off the as much of the top right 2 pins (27,28) as possible
On the left side of the 28 pin socket, cut off pin 1, and bend pin 2 out at a 90 degree angle Insert the 28 pin socket into the 24 pin socket at K1,ensuring that the backs of both 24 and 28 pin sockets are flush. The first 2 rows of the 28 pin shocket should be haning over the front of the 24 pin socket
Solder a wire trace to the bent back pin (pin 2) and the via shown in the picture
program your 2764 EPROM with the centipede single rom image provided Insert into the 28 pin socket as shown above

Notes:
24U kit
strapped for 2732
Cut pin #2, isolate from GND
old CS (18) -> pin #2
new board: cut CS (18) on 24 pin to -> CS (20) on 28 pin run CS (20) on 28 pin to to ground

newest board: just set jumper for dedicated. plug_and_play_adapter.bin