Yamaha 2064 No sound but Test audio working

[hemant_2222]

Hello Guys,

Greetings!

Hope you all are doing well.

I am looking for suggestion on Yamaha 2064. The problem with this receiver is that it has no sound however when the test tones are activated it does outputs from all the speakers. It is working in two channel stereo mode but when you select other sound modes, it doesn't. The last time it had a problem, I had replaced the DAC
PCM1681DBQR - IC263 and it worked fine.

Other issue with it is one of the STK ICs is getting more heated then the other one but that can be looked at later.

I have injected audio in the AUDIO5 input in my setup and could not find two inputs to the IC263. I only have input (from DSP IC) on the DATA1 PIN6, others DATA PINs 2 and 3 (IC PIN 11 and 12 has no input) in normal operation. Again, when I test it with Test Aution, I get a signal on the pin 11 (DATA2) and DATA3 has no signal.

I have reset the receiver to factory default but to no avail.

Could anyone please suggest, where to look for.

Thank you for reading this post. Please advise, if you have any suggestions.

Thank you for your help!

Regards,
Hemant

[ngvuanh]

It's been awhile so not sure if you have shorted this out or not. Anyway, IC263 is fine. I would look into DSP firmware with self diagnostic mode.

[hemant_2222]

Hi ngvuanh,

Thank you for checking.

I did go through the Self Diag mode and I am getting these two parameters, as follows;

T1 Bus: NoEr and EEPROM Bus: OK

Did i check what you requested. Also, I checked the analog audio input ( from Audio5 Input is reaching the capacitors, C2634 and C2641 and I think they are heading towards the PCM2611 (IC261).

I'll check the input and output of this IC261 and let you know.

Thank you for your help!

Regards,
Hemant

[hemant_2222]

Also, I observed one thing that the IC262 (from the schematic) is not present on the top side of the PCB. Please see attached. Am I looking at the correct service manual 😨

[ngvuanh]

Also, I observed one thing that the IC262 (from the schematic) is not present on the top side of the PCB. Please see attached. Am I looking at the correct service manual 😨

Wow, I would clean the board first thing first.

[hemant_2222]

Hey ngvuanh,

Thank you for including this step. I did clean the control PCB but the result is same. But for sure, the board is different than the one we are reffering to in the schematic.

The board has PCM9211 (which is marked as IC261), which includes the ADC. I checked the ADC input at pin 48 and 49 and it is there. The outpu at the pins 17,18,19 and 20 is also showing some sort of band type signal on the Oscilloscope. I have attached the PCM9211 datasheet for your reference.

As a last resort I am thinking of changing the IC263 but that is too far unless confirmed.

Please suggest, what else to look for. ☺

Thank you,
Hemant.

[ngvuanh]

You would need to confirm your unit exact model. Then find service manual to review block diagram for audio, digotal/analog.
I don't think you wanna touch ic263 because it is DAC, and your test tones played on speakers. You also replaced it, so it is fine.