Raiden DX: sometimes battery?

[shmupsrocks]

Looking up photos of Raiden DX PCBs, sometimes they have a battery and sometimes they don't. Did Seibu ship them both ways?

[PC Engine Fan X!]

Same can be said for Seibu Kaihatsu's Raiden II arcade jamma pcb as well with the on-board lithium battery. This particular battery was used for encryption purposes (this applies to Seibu's Raiden DX pcbs as well if they have a lithium battery installed) -- I had originally assumed that it was used for saving high scores and high score initials upon powering the board down for the night. I had come across a Raiden II conversion kit installed in a Dynamo upright cabinet at the Circus Circus hotel in Reno, NV back in 1995 that did, indeed, save both high scores and high score initials upon being powered down for the night.

On my Raiden II arcade pcb, there's a on-board lithium battery (that has long since "bit the dust") that doesn't save high score nor high score initials upon powering it down for the night though -- but coming across that lone Raiden II pcb with high score and high score initials saving functionality was quite unusual to see/behold at the Circus Circus hotel/casino joint back in 1995.

In retrospect, I have to assume that there was some type of on-board PSU to retain the high scores and high score initals of any standard jamma pcb installed in that particular Dynamo arcade cab -- otherwise they'd disappear instantly upon booting down (assuming if there wasn't a back-up battery installed for such purposes or if NVRAM was present to begin with).

Makes me wonder if there is a possible hack to get a Raiden II/Raiden DX pcb to save both high scores & high score initials to an NVRAM eprom setup to give 'em extra functionality in their twilight/golden years given their ages (you might recall that the American arcade distributor, Fabtek, had the exclusive rights to distribute Seibu released arcade hardware/software including the very popular quarter/token gobbler Raiden II conversion kits back in 1993-1994 stateside).

PC Engine Fan X! ^_~

[shmupsrocks]

So the battery II/DX boards do save high scores and the non-battery boards don't?

If the battery is also used for encryption, are the non-battery boards non-encrypted from the factory while the battery boards are encrypted?

[PC Engine Fan X!]

The Seibu Raiden II & Raiden DX pcbs are still encrypted regardless if there is a lithium battery on-board or not. Both Raiden arcade pcbs didn't come with high score & high score initials saving functionality from the get-go.

PC Engine Fan X! ^_~

[MameHaze]

Early Zero Team revisions (which is almost the same hardware) use the battery to store the video encryption keys, if the battery dies you get scrambled sprites.

There are even official(?) reprogram sets for those when it fails so you can attach a new battery and rewrite the keys.

Later revisions just upload the keys every boot so the battery is redundant.

AFAIK all Raiden 2 / DX sets upload the encryption keys every boot tho, so unless some of the early ones don't and we haven't noticed, I don't think it is used for encryption there, maybe it was planned for that same functionality tho?

[Vexorg]

My Raiden DX board didn't have a battery on it when I bought it. I assume it had one originally and it had been removed at some point. It has a bit of sprite glitching, but I don't think it's anything related to encryption.

[MameHaze]

If the encryption keys were lost the sprites would simply be garbage. As I said, R2/DX reprogram the keys every boot. The odd bad sprite is probably a bad chip (RAM, TTL) somewhere.

[shmupsrocks]

I still don't understand why some boards have a battery and some don't. What does the battery do that it doesn't do when it's not there?

[Casey120]

As far as I remember the battery on the original DX board was used for saving the high score but once it dies the high score save code is also lost so replacing it does not work , mine came with battery but HS saving didn't work any more so I just removed it .

[MameHaze]

seems fairly unlikely, the protection devices don't supply any kind of code to the main cpu, so unless it was a magic string in ram being kept alive I can't see it (and that would be very silly from a design point of view)