Jittering Atari 2600 paddles... Due to the console?

[Sceptre_JLRB]

Hi there,

 

After a long time struggling with 2 pairs of jittery paddles, I've tried a brand-new CX30+ ones, released for the new Atari 2600+ console and thus expected to work perfectly. However, I still have the very same issue with them.

 

In all 3 paddle pairs (2 old CX30, thoroughly cleaned and repeatedly checked, and 1 new CX30+) I have kind of a light 'basal jittering' when the knob is untouched, although the movement can be accurately controlled when moving the knob. This occurs equally on both controller ports and with the 2 paddles of every paddle pair. It is noticeable in a number of games (Breakout, Canyon Bomber, Video Olympics, Kaboom!) but imperceptible in some others (Warlords, Tac-Scan, Night Driver), though.  

 

Here is a video showing the issue:
https://mega.nz/file/Pc9BmRBI#Z95BfVxucgo5CYk8Z6KGtofTelE1x1BDo_-94wezwR4

 

My console is a recently adquired NTSC 'woody' 4-switches Atari VCS (1980). Not sure if related, but I noticed (originary by RF and later by composite video mod) the video signal has some artifacts (i.e., dirty colors; image has kind of a 'shadow' effect at sprite edges, being somehow 'splitted' into two different images imperfectly synchronized) which I'm not completely sure even if they are normal, as showed on this topic including photos: https://forums.atariage.com/topic/355896-possible-problem-with-atari-vcs-composite-av-mod/#comment-5336284

 

So my questions are:

1) Could this paddle 'basal' jittering be due to the console itself? Maybe to a damaged component (perhaps a resistence) in the PCB, responsible of processing the signal from the paddle potentiometer? Or could it be rather caused by some defect in the TIA chip and so related to the aforementioned picture issues?

2) Has anybody experienced this kind of problems? Are there any possible solutions?

 

Thank you very much in advance for your help. Any comments, suggestions and ideas are more than welcome!

[Zooang]

Hi I got my new cx30+ paddles with the 4 in 1 cart today from Amazon and I have the same problem. They actually work fine on the 2600+ but they do this on my original 7800 and my 2 2600 Jrs. Here is a video of it happening on my original 7800. I think I will return these paddles. It is really disappointing as I thought they would be a more reliable solution to the jittering of many original Atari paddles. 

Edited February 2 by Zooang

[Sceptre_JLRB]

Hi!

Thanks for commenting on your case. I haven't found the cause of the problem yet, but I'm convinced it could be due to some electronical components damaged in the console itself, typical issues of a 45 y.o. piece of hardware. Don't have the proper knowledge to afford or fix the problem, though.

[+-^CrossBow^-]

Pretty sure this is normal behavior as I've seen this with both 2600s and 7800s. The paddles are read as analog values. That reading isn't static and will shift a bit +|- constantly. Same thing happens on a 5200 even when you have the loopback board installed to dial in the adjustments. As long as the paddle movement itself is smooth and not skipping about when moving them, then you are good to go. 

 

In the case of the paddles, they pretty much just go straight to the paddle pin lines on the TIA itself. As the TIAs aren't made new and are becoming more and more difficult to get, I wouldn't be concerned about this. 

 

Again, when I think of jittery paddles, I think of when using them to play breakout and while moving it left, it jerks back a pixel or two to the right even when I didn't move it in that directly or looks like it skips along at points. But sitting there static and untouched and jittery back and forth a little like you have shown I would not be concerned about.

 

[Sceptre_JLRB]

Thanks for your comments and advice, @-^CrossBow^-. Maybe it's relatively normal, they allow me to play paddle games, after all. I'm just curious about this behavior not occurring on other Atari 2600s, possibly related to TIA 'exhaustion', as you indicated.

[+-^CrossBow^-]

1 hour ago, Sceptre_JLRB said:

Thanks for your comments and advice, @-^CrossBow^-. Maybe it's relatively normal, they allow me to play paddle games, after all. I'm just curious about this behavior not occurring on other Atari 2600s, possibly related to TIA 'exhaustion', as you indicated.

Well, I'm pretty sure I've seen that behavior on just about every 7800/2600 I've tested over the last 2 - 3 years since I specifically started to add Paddle checks as part of my diagnostics. On pretty much all of them, there are spots you can set the paddles on the screen where they will do this. But when actually playing the game, they still have smooth motion back and forth as needed and only exhibit this when left sitting idle.

 

Again, these are analog signals being read and as a result, they will shift about in the values that are being read by the console. Not a ton mind you, but enough that it could cause this effect when you have the paddles in a position that borders between being in one position vs another and the paddle read is fluctuating just enough to cause it to jump back and forth between those positions. In both of the video posted from you and the other member, you have the paddle in about the same position when you show this happening.

 

There isn't much between the TIA paddle pins and the controller port. There is I believe 1 resistor and ceramic capacitor that are in the mix but they aren't components that are likely to go bad. Although that said, they could be slightly out of spec and over time the TIA has become much more sensitive to this and it might be possible to replace those components with tighter spec'd ones to see if it makes a difference.

 

[Sceptre_JLRB]

Thanks again for this detailed and concise explanation and for sharing your knowledge. The best part of the issue is learning new things about it, for sure. 👍

[BIGHMW]

@-^CrossBow^- The same thing happens when I use my CX80 trak-ball (even in "TB" mode) when I ply the trak-ball hacks of Centipede, Millipede, and Missile Command on both my TRRS-modded 2600 Jr. and my 7800 (RCA-modded). Would a little WD40 do the trick??? that's what I used to clean up the nearly-40 years of dirt inside the casing of my 5200 trak-ball and sprayed all the circuit board and added the gold-contact pads to it. If not, then is there still any place I can order online for something like analog TV tuner cleaner to get rid of the jitteriness in both my newly-acquired CX30 paddles (when they come in) and my CX80 trak-ball??? The last time I got some was from Radio Shack in the late-80s to get rid of the scratchiness from a volume control of a vintage 1960s Panasonic stereo receiver my late father used BITD.

Edited February 3 by BIGHMW

[+bent_pin]

@BIGHMW you can get contact cleaner at hardware stores and some big box stores.

[Sceptre_JLRB]

None of that worked to me, the jittering is still present.

[Zooang]

I made an interesting discovery. I tried the faulty cx30+ paddles playing Breakout with a UNOCART on my 7800 and it plays much better compared to the included 4 in 1 cart. The problem is mostly fixed and there is only very slight movement when idle.

[jhd]

 

For what it's worth, I once had a PC with a no-name ISA joystick expansion card. (This was not a sound cart or a multifunction card; it only had a joystick port.)

 

This thing jittered so very badly that it was almost unplayable. I tried several different joysticks and the results were the same. 

 

I attributed the problem to cheap or out-of-spec components on the card. 

[Varanis Ridari]

Not a scientific solution by any means, but as others have stated, this is an analog value, like a modern gamepad joystick, controlled by potentiometers with 280/290 degrees of turn (if I recall correctly).

 

Sometimes the luddite solution of blowing port connectors, reseating the plug, or gently repositioning controller wires can clear up whatever interference there is and stop the "hopping".

 

Doesn't seem to be every game either, but most often happens on Breakout in my experience.

[Sceptre_JLRB]

On 2/12/2024 at 11:32 PM, Varanis Ridari said:

Not a scientific solution by any means, but as others have stated, this is an analog value, like a modern gamepad joystick, controlled by potentiometers with 280/290 degrees of turn (if I recall correctly).

 

Sometimes the luddite solution of blowing port connectors, reseating the plug, or gently repositioning controller wires can clear up whatever interference there is and stop the "hopping".

 

Doesn't seem to be every game either, but most often happens on Breakout in my experience.

Interesting! Sometimes the simpler way is the best. I'll try it! Thanks for the suggestion.👍

[VerminousCoot]

I also have some jittery, brand new CX30+ paddles. Compared to a Hyperkin Trooper on the same Atari 7800, they're pretty bad. Video: