Concept 2000 TV+4 (pong clone) "player" issue

[jschaap26]

I've got a Concept 2000 TV+4 Pong clone I purchased from eBay. Amazingly, when I hooked it up to an old LCD that I picked up from a Goodwill (has coaxial in) it worked. However, there is an issue with the "players" only being able to move from the top of the screen to just below the middle. I opened up the the slide controllers and the main unit looking for a pot I could adjust to fix this issue but found nothing. I attached a picture that shows the lowest point the players will go when I have the paddles (or sliders?) all the way at the bottom of their range.

 

I would greatly appreciate any insight someone may have on how to fix this

 

[emerson]

Do the paddles move smoothly or do they jitter? My first suggestion would be to take either contact cleaner or 91% isopropyl and clean the pots. Open up the controllers, get your cleaning solution inside the pots and work them back and forth for a bit. Add more cleaning solution and work them some more, then blow them out with canned air or an air compressor to dry. It may take a few cleaning cycles.

 

You can always remove the metal shroud on the pots for a more thorough clean but that can be tricky, do so at your own risk.

[mr_me]

If both paddles stop at exactly the same spot I'd think the problem is within the console.  Pong-story says it's based on a ay3-8500 chip.

[+Stephen Moss]

A circuit diagram would be helpful.

As both controllers stop at the same point I would think the problem lies with something that is common to both such as power or a reference voltage somewhere that is used to define either the centre point  or end point of the paddles that needs adjusting.

[DragonGrafx-16]

A Pong console with sliders instead of paddles... weird. lol

[TheProgrammerIncarnate]

More resistance = longer capacitor charge = lower paddles. I'm betting the player capacitors are old, maybe you could replace them.

[jschaap26]

Just circling back on this issue. Thanks everyone for you responses.

 

The paddles move smoothly and do not jitter. While the paddles stop in roughly the same place it is not exactly the same place. If I were capable of creating a circuit diagram I definitely would... but then again, if I had that kind of know-how I could probably fix this without any assistance! Haha. I think replacing the capacitors might be a good first step and something I could probably do. I'll just need to figure out what the appropriate modern day replacement should be.

[Keatah]

It's very likely the same capacitors made back then are still available today. Pay attention to Voltage and uF and general shape.