hello guys,
first of all i'm not a qualified repair guy, i am a diy guy and as years pass by i have some experience on repairing eletronics, and i'm hoping someone can share their experience.
i have a marantz sr6012, some times it turns on and works normal, but after a while the sound cuts off or it starts getting distorted and then cuts off.
when this happens there is no audio no matter the source used, and the OSD shows unknow audio signal from the source.
i was reading very carefuly the service manual and it is all pointing for the digital audio block, witch is very complex of course. there is a ic, the IC221 that by the diagram is responsible for all the audio routing and control.
i've put the unit on diagnostic mode and select the analog audio block and no sound from the speakers or pre-outs. so i think even when using pure direct and analog as source it somehow still needs some control from that IC (or other) to operate the analog swiching ic NJU72750AV and the volume ic NJU72343V.
so i started trying to get some measurments and i found that i have 1.8V and 3.3V supplying the IC, so this end is working ok. i will try to scope them to see if there is any kind of ripple messing the IC stability. (order a dso138 scope so i will be waiting for a few days).
i also measured the input signal for that ic and it all showed 1.2V, wich i think is to be expected.
on the pic attached the red circle is where i measured the supply voltages. on the other side of the board there is 2 IC that are converting the 5.2V from the smps to 3.3 and 1.8. the orange circle is where the IC 221 is located.
this is the link for the service manual:
all the relays click and the unit never enters on protection mode.
i didnt had time to do more testing, so this is what i have for now and hoping some of you have stumble on the same issue with other Denon/marantz avr. i think they all work the same way, they allways have some IC that controls all the audio routing, and solution might be the same.
first of all i'm not a qualified repair guy, i am a diy guy and as years pass by i have some experience on repairing eletronics, and i'm hoping someone can share their experience.
i have a marantz sr6012, some times it turns on and works normal, but after a while the sound cuts off or it starts getting distorted and then cuts off.
when this happens there is no audio no matter the source used, and the OSD shows unknow audio signal from the source.
i was reading very carefuly the service manual and it is all pointing for the digital audio block, witch is very complex of course. there is a ic, the IC221 that by the diagram is responsible for all the audio routing and control.
i've put the unit on diagnostic mode and select the analog audio block and no sound from the speakers or pre-outs. so i think even when using pure direct and analog as source it somehow still needs some control from that IC (or other) to operate the analog swiching ic NJU72750AV and the volume ic NJU72343V.
so i started trying to get some measurments and i found that i have 1.8V and 3.3V supplying the IC, so this end is working ok. i will try to scope them to see if there is any kind of ripple messing the IC stability. (order a dso138 scope so i will be waiting for a few days).
i also measured the input signal for that ic and it all showed 1.2V, wich i think is to be expected.
on the pic attached the red circle is where i measured the supply voltages. on the other side of the board there is 2 IC that are converting the 5.2V from the smps to 3.3 and 1.8. the orange circle is where the IC 221 is located.
this is the link for the service manual:
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all the relays click and the unit never enters on protection mode.
i didnt had time to do more testing, so this is what i have for now and hoping some of you have stumble on the same issue with other Denon/marantz avr. i think they all work the same way, they allways have some IC that controls all the audio routing, and solution might be the same.
