Agilent Technologies 856290216 Keyboard/RPG Problems, Keyboard Interface, Keyboard Matrix

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.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.

2.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		LKSNS4	LKSNS5	LKSNSG
LKSCNO	CONFIG	SAVE	R E C A L	L	GHz	MHz	kHz	Hz
LKSCNl	MODULE	TRIG	DISP		9	6	3	BK SP
LKSCNS	P E A K	BW	TRACE		8	5	2
	SEARCH
LKSCNS	FREQ	AUTO	MKR+		7	4	1	0
	COUNT	COUPLE
LKSCN4	SWEEP	SK1	SK2		SK3	SK4	SK5	SK6
LKSCN5	AUX	MEAS/USER	CAL		SGL	COPY	FRE-	SPAN
	CTRL				SWP		QUENCY

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