Denon DNP-800NE Service Manual page 40

1.3. Power Supply Voltage Abnormalities
Check the output voltage. SMPS PCB to MAIN PCB
[CN221 : 1pin] = +12V ± 1.0V, +12V_A
[CN221 : 3pin] = -12V ± 1.0V, -12V_A
[CN221 : 5pin] = +18V ± 1.0V, +18V_OLED
[CN221 : 7, 9, 10pin] = +5V ± 0.5V, +5V_NET
Are there large deviations in the output voltage?
NO
Check the POWER BLOCK in MAIN PCB.
Is there an abnormality in any of the power supply ICs?
NO
TO "1.4. I2C Communication Line Abnormalities"
1.4. I2C Communication Line Abnormalities
Check output signal.
MAIN PCB MCU[U503 : 106(SDA), 107(SCL)pin]
Is there an abnormality in the "Hi" (3.3V) or "Lo" (0V) level?
Check the communication signal. (during startup)
MCU [106(SDA), 107(SCL)pin] to I2C Device
Is an ACK signal returned from each I2C device?
NO
Check the output voltage.
MAIN PCB
[D533 : 0 ohm] = +7V, +7V_A
[D532 : 0 ohm] = -7V, -7V_A
Are there large deviations in the output voltage?
Check each internal connection. If no abnormalities are found, disconnect the AC power supply, allow the internal charge to discharge for around 1 minute and then start the power supply again.
YES
Check the voltage level (when the POWER switch is turned on)
[CN221: 11pin]
"Hi" : 3.3V, "Lo": 0V？
NO
Abnormality in AC detection circuit [PC831] or in [Q271].
Replace any faulty parts.
Or replace the SMPS PCB.
YES
Replace any faulty parts.
YES
Check Soldering or replace for the following parts.
MAIN PCB [Pull-up : [R635, R636], MCU[U503 : 106(SDA), 107(SCL)pin]
Replace the MCU[U503].
Or replace the MAIN PCB.
40
YES
Replace any faulty parts.
Or replace the SMPS PCB.