Denon D-T1 Service Manual page 39

2. The unit will not power on (other cause)
Check of POWER 14V.
SMPS PCB
Voltage is supplied as normal to [CON503 : 1,
2pin].
YES
Check of STB_5V.
MAIN PCB
Voltage is supplied as normal to [FB27, FB28].
YES
Check of STB_MCU_3.3V.
MAIN PCB
Voltage is supplied as normal to [L5].
YES
Check of MCU Interface.
MAIN PCB
[U10 : 7pin] MCU=RST is "Hi".
[28pin] falls to "Lo" when the power button of
[U10 : 28pin] is pressed.
YES
Check the operation of MCU.
MAIN PCB
POWER_EN changes from "Lo" to "Hi" when [U10
: 3pin] is powered on.
With [U10 : 58, 59pin] powered on, start com-
munication with [U5 : SPHE8104] using this port.
YES
Check of STB_3.3V.
MAIN PCB
Voltage is supplied as normal to [U1].
YES
NO
Check the state / soldering for the following
parts.
SMPS PCB
Check the circuits around [F501, D553-D556,
U501, T501, U502, U503, U504, Q501].
NO
Check the state / soldering for the following
parts.
MAIN PCB
Check the circuits around [U25].
NO
Check the state / soldering for the following
parts.
MAIN PCB
Check the circuits around [U26].
NO
Check for issues in the RESET circuit.
MAIN PCB
[R151, R152, D4, C141, C142]
Check for abnormalities in the power button and
its path.
DISPLAY PCB [SW7, ESD3]
NO
Malfunction of MCU
MAIN PCB
[U10, U11]
Check the surrounding circuits.
NO
Check the state / soldering for the following
parts.
MAIN PCB
Check the circuits around [U1].
Check of SYS_3.3V.
MAIN PCB
Voltage is supplied as normal to [Q3 : Drain].
YES
Check of VCC12.
MAIN PCB
Voltage is supplied as normal to [U2 : 5pin].
YES
Malfunction of DSP
MAIN PCB
[U5,U4]
Check the surrounding circuits.
39
NO
Check the state / soldering for the following
parts.
MAIN PCB
Check the circuits around [Q3].
NO
Check the state / soldering for the following
parts.
MAIN PCB
Check the circuits around [U2].