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Post by bennnil on Jan 27, 2023 12:13:19 GMT -5
Hey everybody,
my good old AV receiver onkyo TX NR 555 suddenly stopped outputting video via HDMI.
I think it is only the output side, since the sound input via HDMI works fine and even the configuration screen is not displayed. I have already made a reset without change. Furthermore I have already found the service manual on the forum and testet input and output (see page 103). The inputresolution is correctly identified however the output gives me only a 0p 24b # on the display which I cannot interpret.
I have read somewhere that broken capacitors have been the problem for many people yet I do not know where to start my diagnose.
If you have any idea, I would be greatful if you would share it with me.
Thanks in advance!
Benni
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Post by tjmotter on Jan 27, 2023 19:40:51 GMT -5
I am afraid that I have some bad news for you. The "capacitor issue" was prevalent a long time ago (TX605 era) and hasn't really been seen much since (at least on the HDMI subsystem). Your system is 10 generations newer and the most common fault in that generation is the failure of the main HDMI controller chip. In you case, this would be the MN864787 (Q8401). Replacing this chip can be challenging. IIRC it has 216 pins and a ground lug on the bottom but with the right equipment it can be done.
It has been a long time since I repaired one of these but I recall that you could diagnose the fault by checking some of the voltages on key pins. @tibimaki might recall which pins to check but you should start by measuring the voltage output on each of the voltage rails on this board. You will be looking for:
Q8931 - pin3 - 1.0V
Q8921 - pin3 - 1.1V
Q8941 - pin3 - 1.8V
Q8951 - pin3 - 3.3V
Q8961 - pin3 - 5.2V
One of these is like to measure very low or zero. The MN part uses mostly 1.1V and 3.3V so I would check them first.
HTH
Todd
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Post by bennnil on Jan 28, 2023 9:01:02 GMT -5
Dear Todd, thank you very much for your answer. I have looked for some measuring point but could not find any. Could you give me a hint where to find them? I included a photo. I am normally used to much simpler boards where each pin is marked so soldering is nothing new to me however replacing the chip you mentioned is rather not an option for me. Anyway I would like to find out if a repairshop could be an option so it would be great to know if the chip is the problem. So thanks for your effort so far. PS: Do have have an opinion on whether a repair in the repairshop is a good idea or buying a new one is the better option? I simply hate throwing away electronics but the receiver is almost 6 years old and was about 300€ when i bought it. Attachments:
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Post by tjmotter on Jan 29, 2023 12:37:21 GMT -5
Ok, here is how to look at an Onkyo board. You found the marker on the board that identifies everything in the square area marked as "C". Onkyo will always place the components in the same orientation shown in the box you found so in this case, C8932 and Q8931 are oriented the same way. The picture doesn't show it but you should find R8936 just to the right of Q8931 and also placed in the same orientation. Contrasting, to the right of that resistor are two more resistors (R8935 and R8934) that are oriented in the opposite direction. I have marked C8932 and Q8931 in the picture below to illustrate.  You should also download the service manual for this model since it would tell you what the part number for Q8931 is so that you can more easily find it on the board. Last, note that if you can't find the Service Manual for an NR555, just download the one for the NR656. About 10 years ago Onkyo stopped making manuals for each model and now sets each manual up so that they can cut/paste the schematics between them on shared boards. For example, I didn't bother to download the NR555 and Service Manual and instead, just scrolled through the NR656 manual where I found the HDMI board and the document clearly showed that the schematic was for the NR555, NR656 and several other models. Your easiest fix might be to see if you can find a working HDMI board on eBay. HTH Todd |
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Post by tjmotter on Jan 29, 2023 20:31:12 GMT -5
Here is what I mean about the schematics. You can see from the line on the top that this board (HDMI board) is the same for the NR555, NR656, NR757 etc  also, to be more clear on the board mapping. When there are too many components in too small an area to paint the part numbers, Onkyo will create a "map". In this case, the box marked "C" outlines all of the components in the area marked "C" on the board. I have pointed to the indicators in the picture below.  HTH Todd |
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lsmar
New Member
Posts: 2
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Post by lsmar on Oct 30, 2023 18:49:36 GMT -5
Here is what I mean about the schematics. You can see from the line on the top that this board (HDMI board) is the same for the NR555, NR656, NR757 etc also, to be more clear on the board mapping. When there are too many components in too small an area to paint the part numbers, Onkyo will create a "map". In this case, the box marked "C" outlines all of the components in the area marked "C" on the board. I have pointed to the indicators in the picture below. HTH Todd |
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lsmar
New Member
Posts: 2
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Post by lsmar on Oct 30, 2023 18:55:34 GMT -5
Boa Noite amigos, tenho onkio tx 1009 funcionando tudo normal todas as portas hdmi,saída arc está parecendo a imagem vermelha só quando coloco em um divisor hdmi,se eu não por no divisor hdmi a imagem não aparece. Alguém poderia me ajudar com alguma informação
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