Fix an old paddle controller?

[Keatah]

Ha! That's the same as measuring the outside pins..

[zander21510]

Odds are I'll just stick with my original plan...gotta wait for Fry's to order some linear pots...school and work are busy right now so this project may have to wait. I'll post if I make any progress. Thanks again for the help everyone.

[zander21510]

So I finished the repair! Frys only had one pot so I figure I will just replace one and replace the other one later.

 

Bought a dremmel to grind down the pot shaft and shape it to fit the handle. Oddly though, the notch on the new pot is on the opposite side of the old one so I had to switch the white wire to the other terminal, and the controller works upside-down now.

 

Nice and buttery smooth, and I guess those old pots were some weird type like 750k or something, possibly 1m, because now the paddle handle moves twice as far as the old pot to span the length of the screen.

I attached some pictures, enjoy!

[BigO]

Nice.

Technically, that'll give you finer control. It's not like there's any need for finer control on something like that, but call it an enhancement anyway.

 

It's theoretically possible that if you were measuring the pot in circuit, some other device was causing you to have misleading readings. Unless the resistor part from the old pot is physically broken, you could still measure it out of circuit without the rest of the guts. Still should be able to measure across the two outer terminals if you're curious.

[zander21510]

Nice.

Technically, that'll give you finer control. It's not like there's any need for finer control on something like that, but call it an enhancement anyway.

 

It's theoretically possible that if you were measuring the pot in circuit, some other device was causing you to have misleading readings. Unless the resistor part from the old pot is physically broken, you could still measure it out of circuit without the rest of the guts. Still should be able to measure across the two outer terminals if you're curious.

 

Yeah I played in "Wall Ball" mode and it was very nice.

 

I did measure the pot after I already clipped the wires...perhaps that one was totally broken. i'll try measuring again when I replace the "good" pot...it's still twitchy but not as much.

[Osgeld]

you can try putting a tiny capacitor (like pF range) in series with the middle pin of the pot, it may help dampen jitters, or it may just offset the positioning a tiny bit, dunno how the machine is sampling the pot

 

could aslo try it tween the middle pin and the black wire to form a RC filter

Edited November 19, 2014 by Osgeld

[BigO]

The sampling method: there is a capacitor connected to a digital input and to ground. The cap is charged with a current that's varied by the potentiometer.

 

The console hardware, when instructed by the game software, discharges the cap then allows recharging to continue. The amount of time it takes to charge the cap to a level that is seen by the input pin as a logical 1 or HI varies with the pot position/resistance.

 

The amount of time it takes to charge the cap is measured by the software. Thereby, the software knows the position of pot which correlates to an on screen position.

Edited November 20, 2014 by BigO

[Osgeld]

so its a single shot timer like almost all consoles / computer of the time, adding a cap will probably just offset the position a tiny bit

[+SpiceWare]

Just get new ones. Not worth fixing.

 

http://www.ebay.com/itm/Atari-2600-Video-Game-System-Pair-of-Paddles-/351219561259?pt=Video_Games_Games&hash=item51c651332b

 

Those aren't new. These are, and they work great on a real 2600.

[zander21510]

Pretty old thread to revive, but after...geez...a year and 4 months (not to mention marrying the girlfriend that broke it originally!)...I finally got around to getting a second pot to refurbish the other controller to match my original. Reason it took so long was partially because I didn't have time, partially because for some reason Frys was always out of 500k linear pots!

 

I found out the original repair I did was wrong, the reason the motion was upside down was because the shaft on the new pot was notched the opposite way of the originals. Seeing as how it's apparently impossible to get those pots at Fry's usually, I decided to redo my original repair and re-notch the shaft. Of course, this had the effect of making the paddle lose...my "redneck" repair was just wrapping the shaft in tape till it was snug .

 

Also...after clipping and re-soldering wires a couple times, I ran out of wire from the reset button and had to replace it with a longer wire I cannibalized from an old USB cord. And man I suck at soldering...I got the terminals on the pot soldered just fine, but I didn't do a very good job on the reset button. If the wire was pulled the wrong way it wouln't complete the connection...and this was after the 3rd try of soldering it (and old solder is hard to remove!), so I was able to tuck it in such a way that when the controller is reassembled, it works fine.

 

In the end...I was able to play a fun game of Video Volley Tennis with my wife! The controllers are oriented and work just like the originals, except they travel farther, making it a bit of a challenge/learning curve to position the paddle just right.

 

Barring any other malfunctions, looks like this old $5 garage sale find lives on!