Sony HKDV-900 Maintenance Manual page 17

4. NV-RAM test
n
Do not turn off the power switch during an NV-RAM test
to avoid the risk of the NV-RAM data failure.
Before turning off the power switch, press the "CANCEL"
button to return the display to the test item number.
Set the test item number to "04" using the [+]/[_] button,
and then press the "STORE" button to activate a test.
Writes "ffh" in the every area of the RAM to check that the
written data can be read properly. Next, writes the data of
"aah", "55h", and then "00h" to check the reading.
If the test result is properly, "PA" is displayed on the
7SEG LED. If it is not properly, "Er" indicating an error
is displayed on the 7SEG LED.
n
If "Er" is displayed, see Section 2-3-6, "Troubleshooting
for NV-RAM Test Error" to clarify the casue.
To quit the test, press the "CANCEL" button. The 7SEG
LEDs display returns to the test item number.
5. LED test
Set the test item number to "05" using the [+]/[_] button,
and then press the "STORE" button to activate a test.
(1) All LEDs test result display
When an LED test is activated, all LEDs (including
with the LEDs in a pushbutton switch) first light for
one second and, after that, go off for one second.
This operation is repeated three times, and then
completed. Next, the single test of LED in the push-
button switch is executed.
(2) Single test result display of LED in pushbutton switch
The "HD" button on the leftmost lights for only 300
msec. And then, each button sequentially lights in the
right direction at intervals of 300 msec..
Blinking the "PRESET" botton on the rightmost
means that this single LED tests are completed. Next,
LEVEL LED test is executed.
HKDV-900
(3) LEVEL LED test result display
The uppermost LEVEL LED in the five-LED row at
the left of a rotary encoder in the "MASTER" part
firstly lights for 300 msec.. And then, each LED
sequentially blinks in the down direction.
Blinking the LEDs is sequentially shifted to the right
row of LEVEL LEDs. When blinking the LEVEL
LEDs in "_" part, all these LED tests are completed.
This test operation returns to all LEDs test of (1) and
repeats the tests unless you quit it.
Check to see that all the LEDs are properly operated.
n
If the result is not displayed properly, see Section 2-3-
7, "Troubleshooting for LED Test Error" to clarify the
cause.
To quit the test, press the "CANCEL" button. The 7SEG
LEDs display returns to the test item number.
6. 7SEG LED test
Set the test item number to "06" using the [+]/[_] button,
and then press the "STORE" button to activate a test.
The 7SEG LEDs count down from "99" to "00" at
intervals of 500 msec. as when activating the test mode.
The countdown is carried out repeatedly.
Check to see that the 7SEG LEDs are properly operated.
n
If the countdown display is not properly, see Section 2-3-8,
"Troubleshooting for 7SEG LED Test Error" to clarify the
cause.
To quit the test, press the "CANCEL" button. The 7SEG
LEDs display returns to the test item number.
2-2. Self Diagnostic Mode
2-5 (E)