Does it say RTC-RAM before a bunch of Japanese? I'm currently working on a Dance Maniax DMX that also gives the Error 605 and it says RTC-RAM just below followed by a bunch of Japanese. Pretty sure this is referring to the Timekeeper RAM failure. That's a chip with a battery built inside. If the battery dies, it needs to be replaced, but these seem to be epoxied shut and you can't get inside to replace the battery without damaging it. Therefore you need to buy a new one. I just ordered a new one for this one (M48T58Y-70PC1) from www.mouser.com ($21 + shipping).
I've had to replace one on a DDR Extreme also, and it fixed the problem it was having. Pull out the main computer (with the blue cartridge and CD-ROM on it), open it up, and check to see which Timekeeper RAM you need (it says Timekeeper on it). It's a chip that looks like a small black box. You'll need to desolder the old one and install the new one when you get it...
We finally reached tech support, and they said to hold the test button down for five seconds, and then follow the prompts. It worked! But good to know what happens when the battery dies...
We finally reached tech support, and they said to hold the test button down for five seconds, and then follow the prompts. It worked! But good to know what happens when the battery dies...
We finally reached tech support, and they said to hold the test button down for five seconds, and then follow the prompts. It worked! But good to know what happens when the battery dies...