Player 2 has started firing by itself!

[Col7800]

Hi Guys,

 

my system has developed another strange problem.

 

Player 2 fires without any joypad attached

 

The firing stops once you attach an atari 7800 joypad to the system and it works properly. Once you remove the joypad it starts firing again (repeatedly).

 

Any of you techies have any idea whats happening, and how to fix this?

[Col7800]

Here is a very short video of the problem:

https://www.youtube.com/watch?v=Y4q5zpbPd70

 

It only happens in 7800 mode.

Strange that it stops when the pad is attached. What is the pad doing to rectify the issue?

[+-^CrossBow^-]

Do you happen to have a copy of Stay Frosty 2 to test? Reason I ask is that my 7800 was giving strange lockups..etc with the homebrew Stay Frosty 2. Just chalked it up to the 7800 being a strange 7800. Then I got the Atarivox+ and found out that the 7800 didn't see it at all when connected but that it worked just fine on my actual 2600 units.

 

Finally figured out that on the 7800 the TIA has a bunch more to do with the controller ports than I ever realized and naturally it was the cause of the issues I was also having with Stay Frosty 2. I changed out the TIA on my 7800 and everything has been good go since. Point being, if you have access to it, and the know how, you might try changing out the TIA IC on your 7800. There are other possibilities that could cause what you described as well of course..but yeah.

[Col7800]

Hi Crossbow,

 

yeh, just tried Stay Frosty demo and it runs fine.

Just socketed the TIA and swapped it for a different one, issue remains

 

Unplug the joypad and after a few seconds it starts firing.....

[Col7800]

Sorted!

 

Grounded pin 9 on port 2 with a 6.8k resistor.

Now works correctly

[Dauber]

The topic title makes it sound like you'd better see a doctor...