View Full Version : Diagnosing Common Apple II Problems

August 13th, 2012, 06:13 PM
This is a simple little guide to diagnosing common Apple II problems.

Feel free to add your experiences or expertise.

Running the Apple ROM Diagnostic

The first thing to do when you get a problematic Apple II is to run the ROM Diagnostic check.

It's only available on IIe's and newer and it's not perfect, but sometimes it's helpful to figure out what's going on in there.

What you'll need:

An Apple IIe (or newer model)
Fingers (how were you planning to use the computer without them?)

Now, hold down the Open Apple, Closed Apple, and Control keys. Then, while still holding that key combo, press and hold Reset for a short while, then release.

The screen should fill with little bricks and then display some text.

Here are some possibilities:

On Enhanced //e, this generally means the system is fine, but if you still suspect problems (such as it displaying W{wtem OK ;) ,) continue reading.

On Unenhanced ][e, this generally means the system is fine.

This means RAM is bad; begin posting on the forums.

Garbage Characters

This is a pretty common problem when you buy a new Apple II.

You get it out of the box, flip the power switch, and boom: the screen has random characters on it.

Sure, you could toss it out and get a new one, but why not at least give repair a shot.

Step 1:

What you'll need:

A flat-head screwdriver
A steady hand

The first step in diagnosing the problem is reseating your character generator. Look around your board for a chip with "CHAR GEN" etched next to it. Then, carefully work the end of the screwdriver under the chip, starting from the side without pins. Then, gently work the chip out of its socket, making sure not to bend any pins. Once its out, make sure to keep it facing in the same direction. If the pins are clean, then place the chip back in its socket the way it was, and gently push it into place.

If this doesn't solve your problem, post on the forums. You may need to replace RAM.