Yamaha DME24N, Service Manual, Page: 114 / 289

114
DME24N/DME64N
1-20. RTC Test
Content: Initialize the Real Time Clock of the RTC
controller: RTC-62423 (EPSON), and display the time
renewal.
When the test starts, “2000. 1. 1. (SAT) 0:0” is shown.
LCD Screen
Message
· When an elapsed time renewal error is detected:
NG: RTC DATA ERROR !
1-21. LCD Test
Content: Check visually if entire LCD displays black
and white repeatedly. Check visually that LCD
backlight turns ON/OFF repeatedly. Check visually
the LCD contrast by adjusting to dark
⇔ light.
LCD Screen
q
Make sure that all the screen is shown in black and
white.
The reversing cycle shifts the display every second
repeating it for five seconds.
w
Make sure that there is no dot missing throughout
the screen.
e
The ON/OFF switch cycle of the backlight is changed
every second and repeated for five seconds.
4 r
Make sure that the screen contrast changes when
contrast volume is changed.
Contrast adjustment is operated by rotary encoder.
EXIT: [CANCEL]
2000. 1. 1 (SAT) 0: 0
∗∗∗
20.
∗∗∗
RTC
Fig. 41. RTC Test Screen
EXIT: [ENTER]
∗∗∗
21.
∗∗∗
LCD
Fig. 42. LCD Test Screen
(NOTE)
The contrast adjustment automatically returns to the
original state when it reaches 100% by the rotary
encoder’s rotation in the positive direction. (The
completion of upper limit check)
It is determined as normal if the range between upper
and lower limit is confirmed assuming the level at which
the displayed characters are invisible (0%) when the
contrast is adjusted to be thinner.
1-22. PANEL LED Test ①
Content: Check visually if LEDs and 7-seg LEDs on
the panel light on in the designated order.
In the case of ICP1, check only the lighting of the
SCENE LED.
LCD Screen
q
As for the order of lighting, each lights on one by
one from the left side of the panel (with EXT. CLOCK
first) to the right side.
(Including those of 7-seg LEDs by the segment)
7-seg LEDs turn on in the order of the last three
digits of 1-9, 0 and . (a period).
w
LEDs that can light with more than one colors light
in the order of “green” → “red” → ”orange” (with no
orange when two-colored).
e
When all LEDs have lighted on, all of them brink
five times in one second interval, and then all light
on, which makes the completion of the test.
(All light on to confirm the LEDs’ brightness.)
EXIT: [ENTER]
∗∗∗
22.
∗∗∗
PANEL LED-1
Fig. 43. PANEL LED Test Screen