My Project of Cloning Pong:

This is a true digital rats' nest. :)

Back when I was 11, I wanted to buy some arcade games off Ebay. My parents told me they didn't want me to do that.

I asked them if they would be okay with me buying the TTL logic chips and cloning Pong. They were okay with that.

So, over the next few months I saved up to buy all of the logic chips.

When the logic chips arrived, I started to clone Pong using these schematics redrawn by Dan B.

When using these schematics, I would like to point out that some of the parts in the paddle circuit are wrong, so be sure to compare them to the original schematics.

After "finishing" the project, several things were evident:

  1. The score was being repeated all over the screen.
  2. Each player had ~16 paddles. (There were around 32 on the screen...)
  3. Paddles would stretch to the bottom of the screen.
  4. The clock circuit would crash when the ball would hit a paddle.
  5. Game would not coin up.
  6. ...and others I'm not too sure how to describe!

Here are some thoughts as to what caused most of the problems:

For problem 1: I learned there is a big difference between a 744852 and a 7448. One is CMOS, one is TTL.

For problem 2: I think I bridged 4H with something...

For problem 3: I think something degraded in the paddle circuits, because it wasn't always this way.

For problem 4: I must have bridged something with the clock signal.

For problem 5: I probably soldered something into the wrong position.

For problem 6: Either A). I need to find the words to describe it. OR B). I need some way to jog my memory.

I also made some other mistakes:

I used a SPDT switch instead of a DPDT switch for the Max Score / Game setting.

I was routinely unbridging connections, so I probably missed something.

Other things about the project:

I used over 300 feet of wire. (In 30-foot spools!)

We cleaned several Radio Shacks out of those perfboards.

We probably ended up spending over $300 to do it just because of the prices of perfboards and wire at Radio Shack. After I showed them my level of commitment to the project by saving for more than half a year to purchase the required logic chips, and then I realized I didn't have money for perfboards and wire, my parents stepped in and paid for the rest.

This was before I knew that μf and mfd on a capacitor both meant microfarad. At the time, I searched for capacitors that said mfd and μf since I thought the difference mattered. I think one of the capacitors cost $50 because it said mfd.

I also had recently gotten a label maker so I used it to label major signals.

Some old pictures I found:

This was pretty early into the project. I was only continuing with circuits once I was confident I was getting something that looked good on the 'scope.

I had soldered up several video circuits before actually seeing what it looked like on the monitor. I had the paddles and the net. After seeing this on the screen, I learned that the MHZ of a crystal matters. A 16MHZ crystal in will make things happen too fast, and will prevent the monitor from being able to lock on to the sync signal. A 14.31818 MHZ crystal made the paddles and net appear. Exciting!

Obviously, these pictures were printed awhile back and scanned. I don't know what happened to any other pictures I might have had, but they're probably long gone.

This page was last updated 1/1/2020

I fixed the way I worded some things, added some details, and I also added some old pictures I found.