If you're not experienced to do work on high end audio devices, please do not attempt to repair this set. You should have CRO and other testing equipment to go with it. At least, a Scope-meter is recommended to take waveform and measurements at the digital circuits.
NO POWER
If the unit doesn’t work by no power problem, repair the set according to the following guide.
FUSE / BRIDGE DIODE / THERMISTOR
Solution
Check and replace F901, BD901, TH900, TH901 on SMPS board.
How to troubleshoot (Countermeasure)
1) Check if the fuse F901 is open or short-circuit.
2) Check if the bridge diode BD901 is short-circuit by over current with a digital multi meter.
3) Check if the NTC thermistor TH900, TH901 is normal or open.
If the unit doesn’t work by no ±PVDD problem, repair the set according to the following guide.
Solution
Check and replace F911, Q905, Q906 on SMPS board.
How to troubleshoot (Countermeasure)
1) Check if the fuse F901 is open or short-circuit.
2) Check the Drain-Source or Drain-Gate, Gate-Source Resistance of Q905, Q906 with a digital multi-meter.
If it is short condition, it’s destroyed. Replace it with a new one.
(replace 2 FET at the same time although several FET is OK)
If the unit doesn’t work by no power problem, repair the set according to the following guide.
FUSE / BRIDGE DIODE / THERMISTOR
Solution
Check and replace F901, BD901, TH900, TH901 on SMPS board.
How to troubleshoot (Countermeasure)
1) Check if the fuse F901 is open or short-circuit.
2) Check if the bridge diode BD901 is short-circuit by over current with a digital multi meter.
3) Check if the NTC thermistor TH900, TH901 is normal or open.
Scope-meter
NO POWERIf the unit doesn’t work by no ±PVDD problem, repair the set according to the following guide.
Solution
Check and replace F911, Q905, Q906 on SMPS board.
How to troubleshoot (Countermeasure)
1) Check if the fuse F901 is open or short-circuit.
2) Check the Drain-Source or Drain-Gate, Gate-Source Resistance of Q905, Q906 with a digital multi-meter.
If it is short condition, it’s destroyed. Replace it with a new one.
(replace 2 FET at the same time although several FET is OK)
NO
BOOTING WHEN POWER ON THE SET
The set doesn’t work when press the power button on the front board or the remote control.
MICOM (IC501)
Solution
Please check and replace IC501 on MAIN board.
How to troubleshoot (Countermeasure)
1) Check the 5.6 VA (CN106) and DVCC 3.3 V(IC505) in standby mode.
If there is no 5.6 VA, check the SMPS and if doesn’t appear 3.3 V, check IC505.
2) Check 5.6 VA, +12 V, FL+, FL-, an +39 V when power on the set.
- If the set doesn’t work regardless of what the KEY2 changes high to low while pressing the power button.
X500 and X501 work normally but, if you can not power on the set, replace the IC501 with a new one on the main board.
The set doesn’t work when press the power button on the front board or the remote control.
MICOM (IC501)
Solution
Please check and replace IC501 on MAIN board.
How to troubleshoot (Countermeasure)
1) Check the 5.6 VA (CN106) and DVCC 3.3 V(IC505) in standby mode.
If there is no 5.6 VA, check the SMPS and if doesn’t appear 3.3 V, check IC505.
2) Check 5.6 VA, +12 V, FL+, FL-, an +39 V when power on the set.
- If the set doesn’t work regardless of what the KEY2 changes high to low while pressing the power button.
X500 and X501 work normally but, if you can not power on the set, replace the IC501 with a new one on the main board.
VFD IS NOT DISPLAYED WHEN POWER ON THE SET
When power on the set, any icons or characters on VFD are not displayed.
VFD (DIG300)
Solution
Check and replace DIG300 on FRONT board.
How to troubleshoot (Countermeasure)
1) Check if 39V, FL+ and FL-are output from SMPS to VFD via the main board.
2) Check if the IC501 outputs VFD_RST, VFD_CLK, VFD_CS and VFD_DO to the front board.
NO BOOTING IN CD/USB FUNCTION
After you turn on power key and displayed message in the following order
(HELLO > VOL XX > CD or USB) on VFD, it will not display other message on VFD, and it will not boot-up normally.
NO VCC33, VCC12
Solution
Check and replace IC505, IC509 on MAIN board.
How to troubleshoot (Countermeasure)
1) Check voltage of IC505 pin3 on MAIN board.
If IC505 pin3 (about 4.9 V) & D500 Input 5.6 VA doesn’t come out, check 5.6 VA from SMPS board.
2) If IC505 pin3 (about 4.9 V) is normal, check the PWR_CTRL (IC505 pin2) is high (about 3.3 V).
If PWR_CTRL isn’t high, check pinB2 of IC501 & R524, R5F7.
3) If PWR_CTRL is high, check R5F6, R5F4, R5F5 and if there’s no defective component then replace IC505.
4) If 3.3 V (VCC33) is normal, check 1.2 V output (pin2, 4) voltage of IC509.
If 1.2 V of IC509 pin2, 4 doesn’t come out, then replace IC509.
NO BOOTING IN CD/USB FUNCTION
After you turn on power key and displayed message in the following order
(HELLO > VOL XX > CD or USB) on VFD,
it will not display other message on VFD, and it will not boot-up normally.
CRYSTAL (X500)
Solution
Check and replace X500 on MAIN board.
How to troubleshoot (Countermeasure)
1) If 3.3 V & 1.2 V is normal, check Reset ‘High’ of IC501 pinT12 on MAIN board.
If MAIN_RESET isn’t high, check MICOM (IC101) pin40.
2) If MAIN_RESET is high, check the soldering status of 24 MHz crystal (X500).
3) If the crystal (X500) doesn’t oscillate, check R508, R509, C502, C503 around crystal (X500).
If there’s no defective component, then replace X500.
NO
BOOTING IN CD/USB FUNCTION
After you turn on power key and displayed message in the following order
(HELLO > VOL XX > CD or USB) on VFD, it will not display other message on VFD, and it will not boot-up normally.
SERIAL FLASH (IC503)
Solution
Check and replace IC503 on MAIN board.
How to troubleshoot (Countermeasure)
1) If the crystal (X500) does oscillate, check serial flash (IC503) on MAIN board.
Check pin8(VCC), pin6(CLK), pin1(CS), pin2(DO), pin5(DI) of below waveform.
2) If pin1, 2, 5, 6, 8 doesn’t come out, check damping resistor (R564, R563, R535, R536, R534) of IC503.
If damping resistor of IC503 is OK, then replace IC503. (it need to download program)
3) After change IC503, if it is still not below waveform, check IC501(DSP IC)
After you turn on power key and displayed message in the following order
(HELLO > VOL XX > CD or USB) on VFD, it will not display other message on VFD, and it will not boot-up normally.
SERIAL FLASH (IC503)
Solution
Check and replace IC503 on MAIN board.
How to troubleshoot (Countermeasure)
1) If the crystal (X500) does oscillate, check serial flash (IC503) on MAIN board.
Check pin8(VCC), pin6(CLK), pin1(CS), pin2(DO), pin5(DI) of below waveform.
2) If pin1, 2, 5, 6, 8 doesn’t come out, check damping resistor (R564, R563, R535, R536, R534) of IC503.
If damping resistor of IC503 is OK, then replace IC503. (it need to download program)
3) After change IC503, if it is still not below waveform, check IC501(DSP IC)
NO BOOTING IN CD/USB FUNCTION
After you turn on power key and displayed message in the following order
(HELLO > VOL XX > CD or USB) on VFD,
it will not display other message on VFD, and it will not boot-up normally.
SDRAM (IC502)
Solution
Check and replace IC502 on MAIN board.
How to troubleshoot (Countermeasure)
1) Check below waveform & soldering status of SDRAM (IC502) on MAIN board.
If pin17(#CAS), pin18(#RAS), pin19(#CS), pin38(CLK), pin29(address), pin2(DQ) doesn’t come out, check damping resistor (R568, R506, R570, R544, R547). If resistor is OK, then replace IC502 (SDRAM).
3) After change IC502, if it is still not below waveform, check IC501 (DSP IC)
NO
BOOTING IN CD/USB FUNCTION
After you turn on power key and displayed message in the following order
(HELLO > VOL XX > CD or USB) on VFD, it will not display other message on VFD, and it will not boot-up normally.
DSP IC (IC501)
Solution
Check and replace IC501(MLC3730) on MAIN board.
How to troubleshoot (Countermeasure)
1) After check them by previous pages about no booting, if the set is still no booting, Check soldering status of IC501.
2) If below bootstrap waveform doesn’t come out, then replace IC501(DSP IC).
After you turn on power key and displayed message in the following order
(HELLO > VOL XX > CD or USB) on VFD, it will not display other message on VFD, and it will not boot-up normally.
DSP IC (IC501)
Solution
Check and replace IC501(MLC3730) on MAIN board.
How to troubleshoot (Countermeasure)
1) After check them by previous pages about no booting, if the set is still no booting, Check soldering status of IC501.
2) If below bootstrap waveform doesn’t come out, then replace IC501(DSP IC).
Continued by next post
