Help with Onkyo TX NR 838

[madan1]

Re: Help with Onkyo TX NR 838

Main channels have higher mV, then the surround ones, if I remember correctly.
It never happened to me, that it did not reach the required voltage. It happened that the voltage was raising to fast, which showed me, that there is still a problem.
Just make sure, that you have 9-11mV, at 6 minutes after startup.

You remember correctly.. but why? All channels are identical, so I believe this is onkyo's way to cool down a bit their units. Other possible explanation would be the heat gradient of the heatsink.. but from what I've seen, if all channels are running, the heatsink temperature is the same ( +/- a couple of degrees ) everywhere on its surface... so what's the point of having different settings on similar components?
If the channels are identical, I always set the same idle current on all of them and aim for the higher end of the mV

[madan1]

Re: Help with Onkyo TX NR 838

Today i also measured the voltages and find out that the VOLH Voltage is normally between 0,47 and 0,5 V. But in the SM the graphic shows a voltage near 3,3V during normal run. Could this be a problem?

I do not know what's running on VOLH, but yes, it could be ( and most likely is ) causing issues.
See what's using that Volh and just try to use it ( like video/audio processing, OSD, HDMI, component video, ethernet, etc. ).

Otherwise i don't have 64V but only 62V. But i think this is no problem at all.

62V is just fine.

How i can check that my HDMI Board is running well? I'm not sure that there is problem and i want to exclude it.

Regards, Mogli

See above - just test it.. see what is working and what not.

[Mogli1476]

Re: Help with Onkyo TX NR 838

I do not know what's running on VOLH, but yes, it could be ( and most likely is ) causing issues.
See what's using that Volh and just try to use it ( like video/audio processing, OSD, HDMI, component video, ethernet, etc. ).





62V is just fine.



See above - just test it.. see what is working and what not.

Ok! I will do so ...

I will check all the things step by step tomorrow.

But some information i have before. Yesterday i tried to run the test mode 1.01 but it passes and jumps to test mode 4-19. This mode runs until 4-25 with turning the relays on and off. After this test run the messages RouteTest OK! and VideoDetection Ok! appears. After this NG is displayed.

The time on the display continues but nothing happens and only NG is still in the display.

And VOLH is still between 0,46V (LOW Mode) and 0,5V (HIGH Mode). It's the same with the PRE Amp Board uninstalled. I still think there is the problem.

Tomorrow i will check everything and will disassemble the receiver again to find the problem on the Main Board. Maybe some of you have the same receiver or a similar one to check if the VOLH has to raise until 3,3V or something else.

Regards, Mike

[Mogli1476]

Re: Help with Onkyo TX NR 838

Ok! I will do so ...

I will check all the things step by step tomorrow.

But some information i have before. Yesterday i tried to run the test mode 1.01 but it passes and jumps to test mode 4-19. This mode runs until 4-25 with turning the relays on and off. After this test run the messages RouteTest OK! and VideoDetection Ok! appears. After this NG is displayed.

The time on the display continues but nothing happens and only NG is still in the display.

And VOLH is still between 0,46V (LOW Mode) and 0,5V (HIGH Mode). It's the same with the PRE Amp Board uninstalled. I still think there is the problem.

Tomorrow i will check everything and will disassemble the receiver again to find the problem on the Main Board. Maybe some of you have the same receiver or a similar one to check if the VOLH has to raise until 3,3V or something else.

Regards, Mike

Another last question before i will check everything is ...

What voltage should i have at PIN 1 on the HDMI Board connector P901? The SM from the 646 says 3V. But I only measure a voltage of 0,3 .. 0,6v. Is there something wrong?

Yesterday i determined that the HDMI Out Signal is like snow on the Main Screen when I switched to USB, NET or Bluetooth.

Also the Network test can't finished without errors but WLan, Ethernet and Bluetooth is working like it should.

Regards, Mike

[Mogli1476]

Re: Help with Onkyo TX NR 838

Another last question before i will check everything is ...

What voltage should i have at PIN 1 on the HDMI Board connector P901? The SM from the 646 says 3V. But I only measure a voltage of 0,3 .. 0,6v. Is there something wrong?

Yesterday i determined that the HDMI Out Signal is like snow on the Main Screen when I switched to USB, NET or Bluetooth.

Also the Network test can't finished without errors but WLan, Ethernet and Bluetooth is working like it should.

Regards, Mike

So! I'm back again with some more informations. I checked a working TX Nr609 from a friend to be sure which voltage is normal for MPOWER. After Powering on the 609 i measured a voltage of 3,1V on PIN 1 of connector 901. Also like the SM for the TX NR646.
But if i'm measuring the Pin 1 of my 838, there is only 0,5..V during run. This is not normal or what do you think?
I checked Q7016 and changed this too with a working one but it's the same. MPOWER on Q7016 is 3,1V during run and that seems ok i think.
Later i checked the Power PCB for errors and measured 11,7 V at MPOWERD during Standby. After run MPOWERD go down to 0,5..V but MPOWER which comes from Q7009 is Ok with 3,1V.
Is this a normal process or could there be a problem in the Power PCB?
I also changed D9011 and C9015 beside the Relais on the Power PCB but that changes nothing. Is it possible that the relay RL9001 don't work like it should?
Regards, Mike

[madan1]

Re: Help with Onkyo TX NR 838

Well, take out of the board RL9001 and test it.. it looks like it is drawing too much power or the power supply is too weak.

[Mogli1476]

Re: Help with Onkyo TX NR 838

Well, take out of the board RL9001 and test it.. it looks like it is drawing too much power or the power supply is too weak.

I think this was not the problem. I changed the old Relais from my 609 with this one inside my 838 and measured 330ohms on the old one (838) and 550ohms (609). The Voltage is now changed from 8,7v to 9,2v but everything was working like before.
I'm not sure if this is ok but at the moment it works. The relays in the 609 though is not the same but both have 9V Coil voltage and are switching 120A,250V. I don't know the exact difference between both relays.
Otherwise MPOWERD has now 0,52V instead of 0,37V and that means the state for low input on Q7016 is working. Also with 0,37V the receiver works well.

[Mogli1476]

Re: Help with Onkyo TX NR 838

Otherwise I checked the whole receiver functions yesterday and found nothing corrupt. Everything is working like it should. Only the receiver is getting warm and warmer so that i cannot touch most parts of the PRE Amp Board and also the heatsink for the 15V regulators. Is this normal?

The receiver works and works and works, tested with every hdmi source, flat tv and loudspeakers. Only the heat growth seems not ok for me but the receiver runs for approx. 2 hours and all was ok.

[madan1]

Re: Help with Onkyo TX NR 838

Onkyo receivers tend to run very warm. Unfortunately I did not measure the temp. of the units I was fixing so cannot tell you if yours is running hotter than it should.
Currently I have a Cambridge audio receiver and here are some measurements:
65-80 degrees on the main heatsink ( for the power amplifier )
55-65 on various voltage regulator heatsinks ( 3 or 4 of them )

I've not noticed excessive heat coming from the pre amp board of a properly working amplifier. Once I had a such case when there was an interrupted path to one of the drive transistors and several components were getting very hot, but the channel was still producing sound.
If you really think that your pre amp board is getting too hot and do not have the means to measure the temperature ( like thermal camera, infrared thermometer, thermo-couple, etc. ) you can use sticky thermal printing paper ( stick it to the transistors and see if any of them get hotter than the rest ).

[tibimakai]

Re: Help with Onkyo TX NR 838

I believe, that the fan should kick in, around 60C.
I have replaced the internal fan, with a laptop cooler's fan(same size), that had an adjustable speed controller and I have adjusted for low fan noise. USB cable, was plugged in into my TV's USB port. So every time the TV it was on, the fan would be on as well.
The latest receivers, don't even have a fan, they run much cooler. There is no idle current adjustment either.

[Mogli1476]

Re: Help with Onkyo TX NR 838

Onkyo receivers tend to run very warm. Unfortunately I did not measure the temp. of the units I was fixing so cannot tell you if yours is running hotter than it should.
Currently I have a Cambridge audio receiver and here are some measurements:
65-80 degrees on the main heatsink ( for the power amplifier )
55-65 on various voltage regulator heatsinks ( 3 or 4 of them )

I've not noticed excessive heat coming from the pre amp board of a properly working amplifier. Once I had a such case when there was an interrupted path to one of the drive transistors and several components were getting very hot, but the channel was still producing sound.
If you really think that your pre amp board is getting too hot and do not have the means to measure the temperature ( like thermal camera, infrared thermometer, thermo-couple, etc. ) you can use sticky thermal printing paper ( stick it to the transistors and see if any of them get hotter than the rest ).

For sure I have an infrared thermometer ;-) The next time i will measure the hottest parts in the receiver and post it here to check if everything is Ok.

I'm not sure yet but i think the Driver Transistors TTA/C 004B on the Pre Amp Board have had approx. 70 degrees after my last measurement but i will post actual values next time.

Regards, Mike