Installing Eproms in a Data East Pinball Machine


To install your eproms, you will need:


Updated eprom chips


A small, flat blade screwdriver or an eprom extractor tool - available in our online store for $8.00



Please note: installing updated eprom chips in your game WILL wipe out any high scores or game customizations. Be prepared to change any settings (enabling Free Play mode etc) when you replace the chips.

Follow these instructions carefully! I am not responsible for any damage you may do to your game by improper handling or installation of chips. If you are confused by anything, or need further instructions or clarification at any time, contact me and I will help!


Unlock and remove the backglass from your machine. Your machine should have keys for the backglass lock, most always put on a hook inside the coin door.

Make sure you ground yourself on a grounded part of the machine, be it a side rail, ground strap etc.

Unlatch and swing the light insert board open.
Behind the light board, you will see the circuit boards that control your pinball
In the upper right corner of the backbox, you will find the largest board. This is the CPU board. Toward the upper left corner of this board is the CPU eprom in socket 5C. This should be just to the right and below the battery pack. Now is a good time to change the batteries if they haven't been changed in the last year.
The socket with the C to the right of it is socket 5C. Your CPU eprom is in socket 5C. Note the "notch" to the right side of the eprom. When you replace this eprom, it is important that the notch goes in the same direction. In the case of Data East games, the notch goes to the right side of the game on the CPU board.
This photo shows the eprom in the socket from the side. When you remove the eproms, it is important that your eprom puller or small flat head screwdriver is placed between the socket and the eprom, not the socket and the board. Prying the socket off of the board can do serious damage to the board, requiring expensive repair work.

This photo also shows in closer form what the notch on the chip looks like.

Using your small flat-blade screwdriver, insert the tip between the eprom and the socket, and pry slightly, just enough to start to remove the chip from the socket. Alternate between the sides of the chip until the chip is out of the socket. It is important to do this slowly in small increments so you do not bend the legs of the chip. Place the removed chip carefully aside, perhaps in the anti-static foam your chip is shipped in.
In this photo, the socket is empty and ready for the new eprom.
Carefully remove your updated chip from the anti-static foam it was shipped in, and verify it is the correct chip for the socket (same number of legs, same shape and size etc)

Line up the chip, noting the notch is toward the right. The easiest way to line the legs up is to line up one side of the chip without inserting the pins into the socket, and gently roll the chip toward the board until the legs are lined up for both sides of the socket.

Once the chip is lined up, apply gentile pressure to the chip, slowly pushing it into the socket.


This photo shows the new chip installed, nice and snug in its socket. Take a closer look, and make sure no legs are rolled under the chip, or hanging outside the socket. If so, you could damage the chip and the board when you turn the game on. The legs of the chip are delicate, and are easily damaged with improper handling.
Next, with the light panel swung open, lift the display and speaker panel out of the backbox, and rest it on top of the playfield glass. Note the display board, attached to the back side of the display.
There are 2 sockets on the display board, labeled ROM 0 and ROM 1. Note the notch orientation, toward the right of the photo. Using the steps outlined earlier in this document, replace the eprom at location ROM 0 with the updated chip, making certain to keep the notch in the same orientation (in this case, the notch goes toward the backbox. Some games use both display ROM sockets, the label on your replacement chip will tell you which socket the chip needs to be installed in.

At this point, you are ready to power the game up and play a few games.

Questions? Comments?

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Last updated Wednesday June 13, 2007