Yamaha MX61, Руководство по обслуживанию

Страница: 58 / 93

⑤
⑦
⑨
④ ① ②
③ ⑥ ⑧
DGND LDGND
AGND
■
DM CIRCUIT BOARD CHECK METHOD
The DM Circuit Board is provided with test points for service check purposes.
Check the test points on the DM Circuit Board if the following symptoms appear.
Symptoms and check items
1. No LCD display with Power SW ON
--> Check
items ① to ④ and ⑦ sequentially.
2. No sound or distorted sound --> Check items
⑤
,
⑥
,
⑧
and
⑨
sequentially.
DM Circuit Board (ZA675600)
TEST POINT
NO. Test Point Circuit ID Circuit Judgment criteria Mesured GND Measured by
Parts with
possible defect
① TL505 +5D
5V power for
digital circuit
5.0V ±0.5V
DGND
(TL509)
Multimeter IC502
② TL506 +5LED
5V power for
LED drive circuit
5.0V ±0.5V
LDGND
(TL510)
Multimeter IC502
③ TL507 +3.3D
3.3V power for
digital circuit
3.3V ±0.3V
DGND
(TL509)
Multimeter IC504
④ TL102 +1.2D
1.2V power for
digital circuit
1.2V ±0.2V
DGND
(TL509)
Multimeter IC104
⑤ TL504 +9A
9V power for
analog circuit
9.0V ±1.0V
AGND
(TL508)
Multimeter IC503
⑥ TL319 +5A
5V power for
analog circuit
5.0V ±0.5V
AGND
(TL508)
Multimeter IC312
⑦ TL101 /RESET
CPU & memory
reset signal
3.3V ±0.3V
DGND
(TL509)
Multimeter IC102 or IC103
⑧ TL324-TL325 DACL OUT
DAC Output
L channel
There shall be audio output
without distortion.
– Signal Checker IC101 or IC310
⑨ TL326-TL327 DACR OUT
DAC Output
R channel
There shall be audio output
without distortion.
– Signal Checker IC101 or IC310
58
MX61/MX49