BEFORE YOU START: Familiarize yourself with the LaserWriter Plus Technical
Procedures, especially the section on the built-in diagnostics. Be sure to
follow proper ESD procedures when replacing ROMs.
When using the built-in diagnostics of a LaserWriter Plus to test the ROMs on
the I/O board sometimes an error code will occur that the instructions on
error codes in the LaserWriter Technical Procedures do not help with. In all
cases, only the last 2 digits of the error code are of concern.
If the error code was 024B 1E08, the H3 ROM and/or L3 ROM would be bad, or if
the error code was 024B 1E80 the H7 ROM and/or L7 ROM would be bad, as
indicated by the LaserWriter Plus Technical Procedures.
Now, suppose that the error code received is 024B 1E0A, since only the last 2
numbers have any meaning, we are only concerned with the "0A" at the end of the
number. Decoding this error code becomes more difficult because error codes
are added together if more than 1 ROM set is detected by the built-in
diagnostics as bad. The addition is of 2 hexidecimal numbers so adding 08 and
02 in hexidecimal gives 0A and the corresponding error code 024B 1E0A. This
indicates that there are possibly 4 bad ROMs instead of 2. In this example,
the possible bad ROMs are either H3 or L3 and H1 or L1. This was determined by
checking which of the error codes would add up to "0A" in hexidecimal.
Below is a list of other possible error codes that might occur. This list only
gives those that would indicate 2 or more sets of bad ROMS. Be sure to refer
to the LaserWriter Technical Procedures for more information on running and
diagnosing the failures. If the error codes indicate several bad ROMs, the
failure may be in the I/O board itself. In this event, exchange the I/O board.
ERROR CODE POSSIBLE BAD ROMs
Lower Bank
XXXX XX03 H1, L1, H0, L0
XXXX XX05 H2, L2, H0, L0
XXXX XX06 H2, L2, H1, L1
XXXX XX07 H2, L2, H1, L1, H0, L0
XXXX XX09 H3, L3, H0, L0
XXXX XX0A H3, L3, H1, L1
XXXX XX0B H3, L3, H2, L2, H0, L0
XXXX XX0C H3, L3, H2, L2
XXXX XX0D H3, L3, H2, L2, H0, L0
XXXX XX0E H3, L3, H2, L2, H1, L1
XXXX XX0F All 8 LOWER ROMs
Upper Bank
XXXX XX03 H5, L5, H4, L4
XXXX XX50 H6, L6, H4, L4
XXXX XX60 H6, L6, H5, L5
XXXX XX70 H6, L6, H5, L5, H4, L4
XXXX XX90 H7, L7, H4, L4
XXXX XXA0 H7, L7, H5, L5
XXXX XXB0 H7, L7, H6, L6, H4, L4
XXXX XXC0 H7, L7, H6, L6
XXXX XXD0 H7, L7, H6, L6, H4, L4
XXXX XXE0 H7, L7, H6, L6, H5, L5
XXXX XXF0 All 8 UPPER ROMs