|
|
Post by mastertech on Jan 17, 2022 15:39:12 GMT -5
That is actually good. You next want to check pins 38 and 39. Now just remember that the signal is possibly attenuated now so listen carefully and you may have to increase the volume on 1 or both units. |
|
|
|
Post by mmartell on Jan 17, 2022 15:41:56 GMT -5
38 and 39 are active
|
|
|
|
Post by mastertech on Jan 17, 2022 15:49:46 GMT -5
Ok. Does the volume level change on 38 and 39 if you adjust the volume control on the bad unit?
|
|
|
|
Post by mmartell on Jan 17, 2022 15:54:00 GMT -5
The volume level does NOT change when adjusted.
|
|
|
|
Post by mastertech on Jan 17, 2022 16:01:59 GMT -5
The volume level does NOT change when adjusted. That could still be fine. I was just asking. Next test pins 41 and 42 and see if any sound. |
|
|
|
Post by mmartell on Jan 17, 2022 16:08:34 GMT -5
Nothing on 41 and 42
|
|
|
|
Post by mastertech on Jan 17, 2022 16:22:29 GMT -5
Ok, so now we know you have audio going through and coming out of part of the volume ic. After it goes out of pins 38 and 39 it goes to ADC and digital processing and then is suppose to come back to the volume ic at pins 41 and 42. So this testing now tells us there is still a problem in the digital realm, besides what you already found and replaced or DAC.
Unfortunately this test unit cannot help you there, you have to find it manually.
We also dont know about the amp section yet but anything there is easily fixable so it does not matter to test it right now.
|
|
|
|
Post by mastertech on Jan 17, 2022 16:29:32 GMT -5
If you look on page 102 there are 2 resistors (R7868 and R7869) on the ADINR and ADINL lines going into the ADC. You should check them and also maybe do and audio test right on ic782, pins 47 and 48 just to be sure the audio in making it to there.
Even those 4 diodes there could be looked at.
|
|
|
|
Post by mmartell on Jan 17, 2022 16:46:34 GMT -5
I already checked pins 47 and 48 of ic782 and the sound is making it there.
But doesn't the sound from the analog inputs go straight to the amp section from the volume ic if no processing is requested by the user, ie stereo mode ? The block diagram indicates such and if that's the case then either the volume ic is defective or it is not being switched by the MCU.
|
|
|
|
Post by mastertech on Jan 17, 2022 17:48:36 GMT -5
I already checked pins 47 and 48 of ic782 and the sound is making it there. But doesn't the sound from the analog inputs go straight to the amp section from the volume ic if no processing is requested by the user, ie stereo mode ? The block diagram indicates such and if that's the case then either the volume ic is defective or it is not being switched by the MCU. Oh, you went to 782 on your own. Ok, did not know. Everything I have looked at is not clear that the audio signal goes directly to the amp lines even in direct or pure direct mode. Even though the ic may have that capability we do not know if Denon programmed that feature in its firmware of the CPU. From the owner's manual: "Sound mode type: Description: "DIRECT" This mode provides a direct input-to-output path with minimal audio processing, bypassing any unnecessary stages for purest sound. So, "minimal processing". What about bass, treble, balance? The volume ic is not capable of these features so it has to be done somewhere else. Also from the manual: "When multi-ichannel signals are inputted, they are mixed down to 2-channel audio and are played back with no additional surround sound processing." Also not capable in the volume ic. Give me your thoughts. |
|
|
|
Post by mastertech on Jan 17, 2022 17:57:25 GMT -5
There is further testing that could be done on the volume ic to see if it is fully functioning but you now know without a doubt there is a problem in the digital section. So time would maybe be better spent trouble shooting there and then when you have analog signals coming back to the volume ic you can go from there. It doesn't really matter at this point if pure direct is programmed unless you just want to make it into a 2 channel stereo receiver.
|
|
|
|
Post by mastertech on Jan 17, 2022 18:17:20 GMT -5
If you want to do 1 more test with the tracer setup you can check for an audio signal after DAC at ic812, pins 41 and 43. This will help narrow it down a little.
|
|
|
|
Post by mmartell on Jan 17, 2022 18:18:54 GMT -5
Excellent information and your audio sniffer will be a useful diy addition to my toolbox so thanks for that.
I'll start tracing out the signal path when I get some time tonight and report back my findings.
|
|
|
|
Post by mmartell on Jan 17, 2022 18:19:44 GMT -5
If you want to do 1 more test with the tracer setup you can check for an audio signal after DAC at ic812, pins 41 and 43. This will help narrow it down a little. Will do. |
|
|
|
Post by mmartell on Jan 17, 2022 18:35:00 GMT -5
No signal on pins 41 and 43 of ic812.
|
|
