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with High Score Save and Diagnostics

"Double Donkey Kong" is a modified Donkey Kong Junior boardset that plays BOTH Donkey Kong Junior and Donkey Kong on a single PCB set. No special wiring is required and no special switches are needed! Toggle between games by simply pressing both the player-1 and player-2 start buttons at the same time. Instantly the game will reset and switch to the other game. The PCB can easily be configured to powerup in either Donkey Kong mode or Donkey Kong Junior mode by moving a single jumper. This is must have for any Donkey Kong enthusiast!

More information about these two games can be found at the (KLOV) "Killer List of Videogames" database. Donkey Kong and Donkey Kong Junior

High Score kit features

The standard high score save upgrade that permanently remembers the top 5 scores and initials for both Donkey Kong and Donkey Kong Junior. Plus many extras features such as deluxe Freeplay, attract mode sound, powerupSelftest, and on-screen Settings.

This is a slightly modified version of the original DK high score save kit. It is altered to contain the Double Donkey Kong code and to save scores for both games. It also allows individual settings for each game.

	Top 5 high scores and initials are remembered permanently for both games, long after the game has been powered off. No batteries to replace ever.
	True "freeplay". No coins required. No need to open your coin door. Full (standard) attract mode while in freeplay mode. See screen shots.
	Selectable attract mode sound.
	Extensive powerup diagnostics automatically tests your board each time the game powers up. See bootup documentation. Selftest is bypassed when switching between games keeping the same quick toggle as before.
	On screen settings menu allows easy changing of game settings and erasing of high scores without having to crawl into your machine and remember complicated DIP switch settings. You can now have different bonus and lives settings for Donkey Kong and Donkey Kong Junior, and you can individually erase high scores for each game. See settings description.

How do I get my board upgraded?

You send in your working Nintendo Donkey Kong Junior 2-board set and it will be upgraded or swapped for a "Double Donkey Kong with High Score kit" and shipped back. See board checklist below to make sure you have a compatible board for the modification. See shipping and packing instructions below.

Board Checklist

Please make sure the board you are sending meets all of these checklist items. If not, email me, as I might be interested in purchasing your incompatible boardset, or applying it towards the purchase price of an already completed double donkey kong boardset.

	Board must be Nintendo type (Sorry I cannot guarantee that a bootleg DKJR board can be modified)
	Board must be Donkey Kong Junior (Sorry, modification cannot be done on regular Donkey Kong boards or Donkey Kong 3 boards)
	40 Pin IC at location 7H (8035) on the CPU board (top board) must be socketed. If this IC is soldered in, please add $5 to help cover the additional labor required to desolder and cost of a new socket. (Note: most boards already have this chip in a socket). Thank You!
	Board must be the 2-board type.
	Board must be already fully working. Non-working boards will be returned at buyers expense. (Sorry, at this price, I can only accept fully working boards)

Shipping your board

When packing your board for shipment, please be static aware (i.e. no plastic bags), bubble wrap is OK. The most common thing that breaks during shipment is the video adjustment pots, anything that can be done to protect those will help. If you remove the heavy metal mounting plate (if it has one), the boardset will fit into a (free) standard USPS priority mail shipping box, as well will save you money on shipping in both directions. If you do send in your boardset without the metal mounting plate, be sure to put something between them so they do not rub together during shipping and cause damage to the boardset.  A sheet of bubble wrap comes in handy here or a sheet of anti-static foam.

How long does the upgrade take?

You will be emailed after the board is tested with an estimate of when it is expected to be completed (shipped). Usual turn around is 7-10 days from when the board is received to when it is ready to ship back, if there are boards in stock that have been upgraded, turn around will be almost immediate.  As a general rule, it takes about a week once the board is received to complete an upgrade. Depending on how many boards are in the queue there may be extra delay.

What happens when you get my board?

When a board is received, it is first thoroughly tested using a special diagnostic test fixture. It checks the CPU RAM, the video character RAM, the video sprite RAM, the DMA controller, the interrupt controller. It also verifies all 5 analog sound triggers, all 7 digital sound triggers, and all 14 background music songs. Both characters sets are tested, as well all 4 color palettes.   Finally the flip screen and reset hardware are checked. Only if/when the board passes all these tests will the upgrade process be started.

What is involved in upgrading my board?

The upgrade involves making modifications to both the video and CPU boards. Most of the socketed components are removed and either replaced or re-used elsewhere on the board as part of the modification. A special daughter board is installed into chip location 7H that contains some custom logic. This daughter board has a movable jumper that can be used to configure the initial game that is selected at powerup. At anytime you can toggle between games by pressing both the P1-start button and P2-start button at the same time. The game will instantly reset and toggle to the other game. The new game will start when both the P1 and P2 buttons have been released. Since toggling requires a hard reset, any remaining credits are cleared.  A second daughter board is installed where the CPU is normally located at location 7F on the CPU board. This second daughter board is the High Score Save and Diagnostics kit.

Sound differences

Some of the sounds in Donkey Kong mode are slightly different that the original sounds. The Donkey Kong walking and jumping sounds have a slightly higher pitch than the original game, and the pounding sound during the introduction of the game is slightly distorted. It is not easily noticeable unless you have an original DK board nearby to compare too. This is probably an artifact that the game is being played on DKjr hardware, and that each board has custom hardware to generate each of these sounds. Note, all of the Donkey Kong music is exactly the same as the original game and all of the Donkey Kong Jr music and sounds are exactly the same as the original. Just a slight variation in pitch for walking, jumping, and pounding when playing Donkey Kong.

You can listen to the difference between the stomping, walking and jumping sounds by clicking here. Special thanks to Michael Bosch of mbdesigns for recording the sounds for comparison.

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