Outerworld Arcade Outerworld Arcade

Cinematronics Sundance Free Play with
Modifications for Bi-Level & 64-Level Monitors

Cinematronics Sundance Free Play


Cinematronics Sundance was originally programmed for use with a 16 intensity level vector display using a 23" black & white tube that was oriented vertically in the game's cabinet. These displays were unreliable when they were new in late 1970s and are exceedingly rare now.

To allow Sundance to run on a wider range of hardware, this modification adds the following features to the game roms:

  1. Bi-Level version which converts Sundance's intensity levels 1-8 to low intensity and 9-16 to high intensity.
  2. 64-Level version which converts Sundance's 16 intensity levels so they will display correctly on a Solar Quest 64-level monitor.
  3. Addition of a free play mode that can be toggled on or off via a dip switch and adds FREE PLAY text when active. In free play mode the attract mode is not a static display, but continues to display the attract mode as if no coins had been inserted.
  4. In free play mode, pressing 1 or 2 player start at any time during the attract mode immediately starts a new game, bypassing the "press start / select number of suns" mode entered after a coin has been inserted.
  5. In free play mode, pressing 1 AND 2 player start during a game adds time determined by dip switch settings.
  6. Switching between free play mode and coin operated mode can be done while the machine is on. Credits are set to zero when switched back to coin operated mode.
  7. The modified roms can be installed into 8k (2716) Cinematronics PCBs using four 2716 eproms OR into 16k (2732) Cinematronics PCBs using two 2732 eproms. The 8k (2716) boards are standard for Sundance. The 2732 eproms can be used to install the Sundance into a board wired for them (Armor Attack and Solar Quest being the common ones). These boards are usually Rev. K and have wire patches on the bottom of the board around the eproms, converting it to run with 2732 eproms.
  8. The game is still in it's original vertical orientation. A horizontal modification might be possible in the future.

Below is a video of the Sundance modification running on a bi-level monitor installed in an Armor Attack cabinet. Control was via a breadboarded control panel.

Installation Overview

Installation is a simple ROM swap.

Power off the machine and insert the new eproms maintaining the same orientation (the notch on the chip) as in the previous chips. Since the roms are sent on new eproms, the legs may need to be bent inward slightly to properly fit in to the sockets on the Cinematronics PCB.

On an 8k (2716) board:
Replace P7, R7, T7 and U7.
Cinematronics Star Castle Free Play 2716
On a 16k (2732) board:
Replace P7 and T7.

R7 and U7 are not accessed and can be unpopulated or can contain eproms left from another game.

Cinematronics Star Castle Free Play 2732

Before powering up, verify that all the chip legs are in the sockets and that all the chips are oriented correctly. Inserting the chip backwards and powering up the game can destroy the chip.

Sundance Option Switches

Donate or Purchase EPROMs:

By donating for your download or purchasing EPROMs, you can help support my work on these projects. Please contact me to donate or place an order.

Bi-level version runs on the bi-level vector monitors used in most Cinematronics games.

16-level version is for the rare 16-level monitors used in the original Sundance cabinets.

64-level version runs on the 64 intensity level monitors used in Solar Quest.

Choose four 2716 eproms or two 2732 eproms, depending on the wiring of the CCPU board. Currently shipping on new ST Micro 2716 or 2732A eproms.

Download ROMs:

Disclaimer: These programs are provided AS-IS. I will not be held responsible for any damages caused by their use.

The binaries include all monitor versions ready for use with either 2716 or 2732 EPROMs.

Latest Releases:

Sundance Free Play v1.0 (01-17-2018) [Download Binary]

Technical Information

Changes to the Sundance code

  1. Memory Bank Fixes: In some instances a few bytes were saved in the original code by not specifying the ROM bank to switch to. The current ram page that was set would do the correct jump. I have added patches to de-link the two so that the ROM bank can be changed without affecting the ram page. This allows the game to be run on 2732s (banks 0 & 1) rather than banks 5 & 6 (the lowest two bits translate to banks 1 & 2).
  2. Intensity Levels: The code has two draw routines: One for the background stars and one for everything else. Both are patched to convert the 16-level ($0-$F) to bi-level or 64-level ($F0-$00, ignoring lowest 2 bits).
  3. Free play: Dip switch selectable free play option. There are a few branches to extra code if the dip switch is set. This extra code does the following: - Starts a game if 1 or 2 player start are pressed in attract mode, bypassing the wait mode for a start press after a coin is inserted. - Adds time, set by dip switches, if both 1 and 2 player start are pressed during game (same as coin insert during game play). - Draws “FREE PLAY” on-screen during attract mode
  4. Removes some garbage bytes at the end of the code and replaces them with $FF.