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Oliver's Replacement Playchoice BIOS

I recently purchased a Playchoice Track & Field PCB that I found, to my dismay, was missing the RPH05 security chip, rendering the board useless. This isn't the first time something like this happen to me. During a time of extensive NES chip testing, I was less than careful removing and installing the EPROMS chips. Long story short, I damaged the security chips in two Baseball PCBs.

For those who don't know, Playchoice PCBs will not work if either the RPH05 security chip or 2764 menu/ID EPROM chip are missing or damaged - the game won't appear on the menu screen, making it impossible to access the game.

What should you do if something like this happens to you?

  1. You can throw the board away.
  2. You can sell the board for parts.
  3. You can download the Playchoice replacement BIOS from Oliver Achten and bring your PCB back to life.

Seems like a no-brainer to me.

(Why not replace just the security chip? From what I've learned on the Internet, the chip can't be read or written to by typical burners making replacement not an option. If anyone has had different information, please let me know.)


From what I can tell from the Internet, Oliver Achten wrote a replacement BIOS for the Playchoice motherboard while creating a system to allow NES cartidages to interface with the Playchoice system. (See Kane's Playchoice Tribute site for detailed information.) I'm not sure if Oliver intended for this BIOS to help damaged PCBs, but it works like a charm.

How it Works

What this BIOS does is replace the standard Playchoice game menu with a custom menu that bypasses the built-in game PCB security chips. This means that game PCBs with missing or damaged security and menu chips will work good as new.

Pressing the channel select button randomly rotates through the PCB game channels and automatically loads them.

Regular Playchoice menu

Oliver's modified BIOS menu

How to Install

    The location of chip 8T

  1. You will first need to download Oliver's hardware description & PC-10 BIOS here.
  2. Then burn it to a 2764 EPROM.
    (If you don't have an EPROM burner, I'd be happy to make you a copy for free, plus the cost of shipping. Contact me to make a request.)
  3. You should carefully remove chip 8T from the Playchoice motherboard and replace it with Oliver's new chip.
  4. Be sure to reference Oliver's DIP switch settings for single or dual monitor systems.
  5. Turn your machine on.

Pros and Cons

As with any solution, there are pros and cons. On the plus side, your broken games will work. You won't have to throw them away.

On the minus side, if you're a Playchoice purist, you won't like not being able to see the menu and game descriptions. In addition, pressing the channel select button randomly selects a game. As far as I can tell, it is not possible to rotate sequentially through the games.

However, if you typically use NES converted games, the menu screen does not accurately reflect the games in your system anyway. You probably have a white board or something else to note the placement of the games, so not seeing the menu might actually make game selection less confusing.

You make the call.

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