HP 3562A, Service Manual

Page: 368 / 570

MODE L 3562A FAU LT I SOLAT I O N
B . Keyboard Check
1 . Press the line switch off.
2. Disconnect cable W1 0 (A1 2 J 1 5) from the A1 2 Mother Board.
3. Connect the power cable and press the l i ne switch on.
4. Reset the keyboard by putti ng A1 5 J9 to the test (T) position, then back to the
normal (N) position (see note).
NOTE
On some A 15 revisions the A 1 5 19 jumper is not in a convenient ocation.
If th is is the case, the keyboard can still be reset using the following
procedure:
a. Press the line switch off.
b. Disconnect cable W1 7 (A 12 j 1 6j from the A12 Mother Board.
c. Connect a + 5V dc power supply and gro und to W1 7, + 5V to the
red wire and ground to the black wire.
d. To reset the keyboard, cycle the + 5V power supply off, then on.
5. The keyboard shou ld respond as fo llows when it is reset:
a. Beeps the beeper and flas hes all the LEDs three times except CR1 2 (Triggering),
CR1 7 (Half Range), and CR1 9 (Half Range). These LEDs w i l l flash on and stay
on since they are contro lled by other assembl ies.
b. Beeps the beeper and then lights the LEDs one at a time in a pattern from left
to right, top to bottom .
c . the bee ain and then al l the I '
test A 1 5
(go to 8-1 5).
7. This test only val idates part of the keyboard, it does not val idate the system bus
i nterface circu its.
8. Press the line switch off.
9. Connect cables W1 0 and W1 7 to the A1 2 Mother Board.
NOTE
The ke yboard cable (W1 0) can easily be connected wrong! A fter
connecting the cable, verify that both rows of pins are connected.
7-5