Compaq Deskpro Workstation AP240 Reference Manual page 190

Power-On Self-Test Messages
Message Beeps*
304-Keyboard or None
System Unit Error
401-Parallel Port 1 2S
Address Assignment
Conflict
403-Parallel Port 3 2S
Address Conflict
Detected
404-Parallel Port 2S
Address Conflict
Detected
410-Audio Interrupt 2S
Conflict
411-Network 2S
Interface Card
Interrupt Conflict
501-Display Adapter 1L, 2S
Failure
* L = Long, S = Short
E-4 POST Error Codes
Continued
Probable Cause
Keyboard failure.
IRQ address conflicts with
another device.
IRQ address conflicts with
another device.
Both external and internal
ports are assigned to parallel
port X.
IRQ address conflicts with
another device.
IRQ address conflicts with
another device.
Graphics display controller.
Recommended Action
1. Reconnect the keyboard with
workstation turned off.
2. Ensure that none of the keys are
depressed.
3. Replace the keyboard.
4. Replace the system board.
Reset the IRQ.
Reset the IRQ.
1. Remove any parallel port
expansion cards.
2. Clear CMOS.
3. Reconfigure card resources and/or
run Computer Setup (F10 Setup).
Reset the IRQ.
Reset the IRQ.
1. Reseat the graphics card (if
applicable).
2. Clear CMOS.
3. Verify monitor is attached and
turned on.
4. Replace the graphics controller.
Continued