Zenith Z-170, Owner'S Manual

Page: 66 / 147

60
In Case of Difficulty
Automatic Tests at Power-Up
The power-up checks are automatically made on the following when the
computer is first turned on:
• Central Processing Unit (CPU)
• Read-Only Memory (ROM)
• User Random Access Memory
• Interrupt Control and Timer Circuits
• Keyboard Microprocessor
• Disk Drive Read
• Disk Drive Seek Function
• Disk Controller
• Disk Direct Memory Access (DMA) Overrun
•
Disk Cyclic Redundancy Check (CRC)
• Disk Address Mark
The following is a list of messages that may be displayed at power-up
or during the self-tests. Possible solutions are also listed. If the suggestions
are ineffective, have your computer checked by a qualified service techni­
cian.
What the Power-Up Messages Mean
+ + + ERROR: CPU fai lure1 + + +
+ + + ERROR: ROM checksum fai lure1 + + +
These two messages indicate the CPU logic may not be working properly.
The checksum message is a result of a mismatch between a predetermined
value and a value derived from the contents of the system ROM. Turn
the machine off, wait 5 seconds, then turn it on again. If the same message
reoccurs, you will need to have your system serviced by a qualified indi­
vidual.
+ + + ERROR:
RAM
fai lure! Address : XXXX: YYYY, Bit: N, Chip XXX + + +
This message indicates the CPU is unable to read from or write to
RAM
or video
RAM
.
If the displayed chip number is a 400 number, the failure
is on the
RAM
board. If the chip number is a 300 number, the failure
is on the Video board.