Tales of the Arabian Nights & Playchoice 10

Have 2 new items in the collection, first is my grail pin, Tales of the Arabian Nights, an excellent top 10 Williams machine from 1996… Unfortunately it has quite a bit of insert issues, with many of them flaking off, and/or becoming raised from the playfield. Fortunately you can buy replacement insert decal sets so its not beyond saving (like the inserts on my ┬áBram Stoker’s Dracula pinball). I currently installed an LED kit from Cointaker but the kit included purple (?) general illumination LEDs which really ruin the look of the game, so going to have to order some regular warm white LEDs. Additional upcoming mods include making the backbox lights animated (originally they were just always on) which will be possible since the LEDs draw significantly less power I can tie them into the play field GI circuits.

Which brings us to another issue, Williams machines use SCRs to dim the playfield illumination (so the lamps are driven by AC), unfortunately this causes 60Hz strobing when you replace the lamps with LEDs. Data East/Sega/Stern machines just use a relay to flash the playfield illumination on and off, so replacing the AC supply in those with a regular SMPS DC supply is easy, unfortunately on the Williams machines it is going to be a bit more involved. First plan is to try and make some kind of board that takes the signals going to the SCRs and runs them into some MOSFETs or Bipolar transistors, to try and dim the LEDs but using DC instead of AC, therefore getting rid of the 60hz flicker. A lot of work? Yes. Worth it? Most definitely. LEDs last a lot longer, generate less heat, and don’t silver over like regular bulbs can, which heats them up even more, melting plastics near them and sometimes even damaging the playfield itself.

So while that project progresses another project has fallen on my lap due to a good deal. Recently got a pair of Nintendo Playchoice 10 boards with cartridges. ┬áThe Nintendo Playchoice is an interesting beast, that did terribly when introduced in ~1986, basically they took a regular Nintendo Entertainment System (NES) and heavily modified it, giving it RGB out (for arcade monitors), a second monitor (for a menu of games and game instructions), and the ability to have 10 cartridges on the motherboard at once allowing the player to choose from up to 10 installed games. The game cartridges were not like regular NES cartridges, they were small, bare boards, that used nice AMP connectors instead of the NES’ card edge connectors (you didn’t have to blow on these cartridges!). They also modified the software a bit, each cartridge had at least 3 EPROMs, one for the game code itself, one for the playchoice extras (like the menu information and instructions), and a security EPROM that had the Playchoice BIOS and such on it. Of course over the years this system has been hacked, allowing other, non Playchoice games to be loaded onto Playchoice cartridges, but I am going to try and keep it original for now.

Unfortunately Nintendo was not using the now standard JAMMA (Japan Amusement Machinery Manufacturers Association) interface but their own proprietary one, so the first order of business was making a Playchoice > JAMMA adapter harness. Additionally the monitors that Nintendo used at the time used inverted video, so no signal would give you a white screen instead of a black one (1v = black, 0v= white), since they were already using these monitors in other cabinets like the Nintendo VS cabinets and such. So off to order some parts to make a video inverter, audio amp, and harness, fun times!

Pics soon

Tuesday, July 17th, 2012 Arcade & Pinball