Agilent Technologies 4284A Service Manual page 79

Also Every time the H P 4284A turned on, the power on sequence (for example, i nitial­
izes the timer on A7) is performed. This power on sequence is checked by watching
the LED array (A7 DS3, A7DS4). See below.
LED Pattern ( 1 ON 0
=
Left
Right
4 5
1 2 3 6 7 8
x X X X X X X X
X X X X X X X X
1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0
o
1 0 0 0 0 0 0
0 0 1 0 0 0 0 0
0 0 0 1 0 0 0 0
o
0 0 0 1 0 0 0
o
0 0 0 0 0 1 0
o
0 0 0 0 0 0 1
o
0 0 0 0 0 0 0
1 0 0 0 0 0 0 0
o
1 0 0 0 0 0 0
1 1 0 0 0 0 0 0
0 0 1 0 0 0 0 0
1 0 1 0 0 0 0 0
o
1 1 0 0 0 0 0
1 1 1 0 0 0 0 0
0 0 0 1 0 0 0 0
1 0 0 1 0 0 0 0
1 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0
OFF )
=
Task
Clears memory card read/write fli p-flop
Turns off memory card power s upply
LED test
LED test
LED test
LED test
LED test
LED test
LED test
LED test
LED test
I nitializes LCD controller
Initializes timer on A7
I nitializes timer on A90
I n itializes A90
Check the bit switch (A7S3)
I nitializes timer on the A-D converter
Initializes PIA chip on A30 or A3 1
I nitializes PIA chip on A40
Clears all interrupt signal
RAM read/write test
Clears RAM
Displays "Copyright" message
ROM cheCk sum test
E E PROM check sum test
E EPROM check sum test for A40 (Option 301 on ly)
Starts the measu rement
3-36