If there are faulty RAM chips in your system, you see one of these messages:

201-Memory error

202-Memory address error

203-Memory address error

If an I/O or parity error occurs, you see one of these messages:

Parity check 1

Parity check 2

The program also displays the number of the segment causing the problem.

Keyboard Controller and Keyboard Check

The computer checks the keyboard controller and keyboard for problems such as failure of one of the keys to release. If there are any errors in the connection between the keyboard and computer, you see this message:

301-Keyboard error

When this message is preceded by a number (XX), the number represents the key (in hexadecimal) that is the source of the error.

If another failure is found, you see one of these messages:

303-Keyboard or system unit error

304-Keyboard or system unit error

Video and Video Controller Check

The computer next checks the video and video controller. If an error occurs, you see this message:

401-CRT error

501-CRT error

Power-On Diagnostics C-3