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Keyboard/RPG
Problems
Keyboard
Interface
Refer to function block G of A3 Interface Assembly Schematic Diagram in the
HP 8560 E-Series Spectrum Analyzer Component Level Information.
A pressed key results in a low on a keyboard sense line (LKSNSO through LKSNS7). This sets
the output of NAND gate U607 high, generating
KBD/RPG-IRQ.
The CPU determines the
key pressed by setting only one keyboard scan line (LKSCNO through LKSCN5) low through
U602
and reading the keyboard sense lines.
1.
2.
If none of the keys or RPG responds, check ribbon cable,
AlAlWl.
(This cable connects
the
AlAl
keyboard to the A3 interface assembly.) The keys are arranged in a row/column
matrix, as shown in Table 8-4.
If an entire row or column of keys does not respond, and the RPG does respond, there
might be an open or shorted wire in AlAlWl.
Table 8-4. Keyboard Matrix
LKSNSO
LKSNSl
LKSNS2
LKSNS3
LKSCNO
CONFIG
SAVE
RECALL
GHz
LKSCNl MODULE
TRIG
DISP
9
LKSCNS
PEAK
BW
TRACE 8
SEARCH
LKSCNS
FREQ
AUTO
MKR+
7
COUNT
COUPLE
LKSCN4 SWEEP
SK1
SK2 SK3
LKSCN5
AUX MEAS/USER
CAL SGL
CTRL
SWP
LKSNS4 LKSNS5
LKSNSG
MHz kHz
Hz
6 3
BK SP
5
4
SK4
COPY
2
1
SK5
FRE-
QUENCY
0
SK6
SPAN
3. Check that all inputs to NAND gate A3U607 (LKSNS lines) are high when no key is
pressed. If any input is low, continue with the following:
a. Disconnect AlAlWl from A3J602 and again check all inputs to U607.
b. If any input is low with AlAlWl disconnected, suspect A3U604, A3U607, or A3U602.
c. Reconnect AlAlWl to A3J602.
4. Monitor A3U607 pin 8 with a logic probe. A TTL high should be present when any key is
held down. Monitor this point while pressing each key in succession.
5. Check that the LKSCN lines (outputs of A3J602 pins 1 through 6) read a TTL low with no
key pressed. (Any TTL high indicates a faulty A3 Interface assembly.)
6. Check that a pulse is present at each LKSCN output of
U602
when a key is pressed.
7. Check that only one input to U607 (LKSNS lines) goes low when a key is pressed.
8. Check that
U602
pin 9 (LKBD-RESET) pulses low when a key is pressed.
ADC/lnterface
Section 8-7