My 7800 is having paddles problems

[Underball]

I asked about this over in the 2600 forum, and got a few conflicting responses, but no hard answers, so I'd like to see if any of teh 7800 Jedi council can help me figure out what's going on.

 

I tried to build a homebrew paddle. Got a 1 MegaOhm pot from The shack, hooked up the center contact to pin 7 (+5v) and one of the outer contacts to pin 5.

 

I get nothing. Harmony cart just cycles through the menu, 2600 test cart shows the paddle input throwing all the way to the right, turning the pot does nothing. If I use a joystick in the Harmony menu to select Kaboom, it throws the buckets all the way to the right when I pug in the paddle.

 

But - my converted SMS light gun (which also uses pin 7) and my CX-80 trak-ball in "TB" mode work fine respectively on 7800 Crossbow, and 7800 CentipedeTB.

 

Lil help?

 

Is it just bad luck with two bad pots from The Shack, or is there possible something else f-ed up in my 7800?

[+Mitch]

I thought pin 5 was for the player 2 pot and pin 9 was for the player 1 pot.

 

Mitch

[Underball]

Either way I get no response.

[+Mitch]

I just check one of my sets of paddles and pin 7 (+5v) is connected to one of the outside contacts and pin 5 (or 9 depending on the controller) is connected to the middle contact.

 

Mitch

[Underball]

didn't help switching them.

[Underball]

At this point, it's gotta be either bad pots from Cellphone Shack, or an errant glob of solder on the 7800 motherboard from when I did the A/V mod, causing a very specific short that only affects the paddles.

 

I'm leaning towards bad pots though. I can't imagine a short on the motherboard that would disable paddle detection, but not negatively affect light gun and cx-80 trak-ball usage.

 

At any rate, I have a pair of standard atari paddles on thier way ePay this week. If it's not the pots and the paddles still don't work, I'll just get another 7800 console.

 

Anyone have a working spare 7800 they can part with for a reasonable price? I don't need and cables or controllers.

Edited July 25, 2010 by Underball

[+Mitch]

Do you have a multi-meter to test the pots with? That would at least tell you if they are bad or not.

 

Mitch

[Underball]

I don't. I've been meaning to get a new one but just haven't gotten around to it.

[Underball]

So yeah, that didn't work. Official Atari paddles give the same exact result as the homebrew ones I built.

 

Gotta be my 7800, any ideas?

[Underball]

Well, Problem sort of solved.

 

I just bought a new 7800.

 

So yeah - once it arrives, I'll likely be selling the other one (with paddle problems) if anyone is interested. It's A/V modded and otherwise in great shape, a few scratches on the silver faceplate, but other than that it's solid.

[BigO]

With a game plugged in, which way do the paddle inputs fail? Do they act like the paddle is turned all the way left or do they act like the paddle is turned all the way right? Behaving like an open circuit or a short circuit could be helpful information to someone who wants to fix it.

 

Do both paddles fail the same way (look at a 2 player pong type game in Video Olympics)? If they both fail the same way and plugging in a set of paddles has no effect, you may have somehow taken out the +5v.

 

 

How do you troubleshoot without even a basic multi-meter? I'd feel like I was driving a car while blindfolded. As a friend of mine says, "You're working like an animal."

 

 

 

[Underball]

With a game plugged in, which way do the paddle inputs fail? Do they act like the paddle is turned all the way left or do they act like the paddle is turned all the way right? Behaving like an open circuit or a short circuit could be helpful information to someone who wants to fix it.

 

Do both paddles fail the same way (look at a 2 player pong type game in Video Olympics)? If they both fail the same way and plugging in a set of paddles has no effect, you may have somehow taken out the +5v.

 

 

How do you troubleshoot without even a basic multi-meter? I'd feel like I was driving a car while blindfolded. As a friend of mine says, "You're working like an animal."

 

both act like the paddle is turned all the way to right.

 

But like I said - the light gun (which also uses pin 7 (+5v) works just fine.

[Underball]

It absolutely was that particular 7800. Just got a new one and my paddles work just fine, with the Harmony and everything.