Odyssey 2 Repair Question & General Question

[BigO]

I recently bought an O2. It's the one with detachable controllers. It mostly works (bought as-is so no complaints here).

I modded it with an RCA jack for the RF cable to get rid of the goofy proprietary connector that hooked to the switchbox.

 

After fiddling and cleaning, I got some games working. But, it does something strange. With either controller plugged in to the player one/left/whatever socket, moving the joystick right causes some bad things to happen. It doesn't exactly cleanly reset the machine or restart the game, but sometimes it appears to. Other times it scrambles the screen.

 

This happens in a game or at the start screen, again no matter which controller is plugged into the first port.

 

Anybody ever seen this happen and resolve it? I'm hoping to maybe save myself from re-inventing the wheel.

 

 

2nd more general 02 question: how do those controllers work? I took them apart and saw 8 sets of contacts, but see people talking about replacing them with Atari joysticks which are only 4 way. Are the 02's really 8 way controllers or is there some trick going on that I haven't figured out?

(Again, laziness, avoiding the wheel reinvention thing...)

[DanBoris]

Second question first. O2 sticks are only 4-way; there are only 5 inputs (4 directions and fire) to the system from each stick.

 

As for the system going crazy when you push the stick in one direction, the only thing I can think of that would cause this is a problem with the chip that interfaces the sticks to the cpu. This would either be IC8 or IC4, not sure which one goes to which port. Both are 74LS365's.

[BigO]

Thanks, Dan. I'll fire up the logic analyzer one day soon and check out the LS365's.

 

Now I'm going to have to figure out what's going on in those controllers and trace the contacts out to the outputs and/or study the schematics. What I saw didn't match what I expected. I couldn't figure how they'd be more than 4 way with not even so much as resistors in there. But, at least I'm assured that using some other controller (Atari probably) wouldn't reduce functionality. These games can't take much loss in play value.

 

I'm off to find and download the schematics that I saw the other day.

[BigO]

Found the service manual: www.digitpress.com/library/techdocs/o2-svc.pdf

 

Looking at the PC board for the controllers, I can now see what they did with the controllers. There are 2 sets of contacts for each cardinal direction, but they're set equally to either side of the associated cardinal point.

Edited July 26, 2009 by BigO