At the request of a friend I was asked to fix the inverted screen issue with Athena.
An hour or so at the hands of the MAME debugger and a couple of false attempts the resulting patch is a simple two byte change to the rom.
In rom up02_p4.rom change these bytes. (actually, the patch swaps them around)
$029e to $48
$02a4 to $3e
Burn a new 27c128 rom and its done. Since we are swapping two bytes, the checksum doesn’t change.
Edit: Tested on a real pcb. Works perfectly as expected 🙂
8 thoughts on “Screen flip for SNK Athena”
Great job as always!Is this a factory issue present on all Athena PCBs?
Yep. Was designed that way. Jamma but not following the standard as such.
It is possible to contact you by email ?
From this site it’s impossible.
You should be able to contact me through here. Sorry I’ve taken so long to reply. Did you want something specific?
Yes, i want to know if if your “high score save” eproms program who saves over 10 millions points for Juno First is still available ?
I am interested.
If you want, you can contact me by mail.
Hi. Sure, I’ll drop you an email. I was thinking that I should just do a blog post on it and put it out publicly.
Do you have project to put the score save patch over 10 millions for Juno First ?
Just wanted to say this worked great on my PCB, thanks so much for putting the time in to figure this out.