Buick 1993 Roadmaster Owner's Manual page 150

Step 4. Press the
AM-FM
button. The radio will display
"000".
Step
5.
Enter the second three digits of the code. The
display shows the numbers as entered.
Step 6. Press the AM-FM button. If the display shows
"-
-
-", the disabling sequence was successful. (The
numbers .matched the user-selected code or the factory
back-up code) and the unit is in the UNSECURED.
mode. If the display shows "SEC", the disabling
sequence was unsuccessful and the numbers did not
match either of the codes and the unit will remain in the
SECURED mode.
C-are of Your Cassette Tape Player
A tape player that is not cleaned regularly can cause
reduced sound quality, ruined cassettes, or a damaged
mechanism. Cassette -tapes should be stored in. their
cases away from contaminants, direct sunlight, and
extreme heat. If they aren't, they may not operate
properly or cause failure of the tape player.
I
Your tape player should be cleaned regularly each
month or after every 15 hours of use. If you notice a
reduction in sound quality, try a known good cassette to
see if the tape or the tape player is at fault. .E this other