Help with Onkyo TX NR 838

[Mogli1476]

Re: Help with Onkyo TX NR 838

http://www.analogmetric.com/goods.php?id=1534

Thanks for this sources. Do you have any experiences with that? Are these trusted sources or don't?

The second source seems to be a good one but shipping is a little bit to much. I'll try to order and give you feedback.

Regards, Mike

[Mogli1476]

Re: Help with Onkyo TX NR 838

Hey friends,

today my newly ordered parts arrived and were installed until now. A first check of the receiver lets me know that it seems to work now.

After turning on i could adjust all idle potis to the value directly after turning on. But after a few seconds the receiver turns off automatically. I tried a new test to turn it on again and the same problem occurs.

I think there is another small problem on the Pre AMP PCB. Tomorrow i will check all parts on the board again.

Otherwise the receiver turns on, there is no overheating problem and no parts were burned or exploded. Maybe some of you guys have the same problem and can help me to fix it?

Thanks and best regards, Mike

[tibimakai]

Re: Help with Onkyo TX NR 838

Did you adjust every pot to 0, at first?
I'm guessing, that you will have to make these adjustments, one at a time, until you are done with all the channels.
You had two channels blown, right?
So, you HAVE TO measure every component, at those two channels.
If you are not sure about something, than compare the measurements with the neighbor channel.
In some spots(1-2), you will have some measurements, that keeps dropping as you measure, make sure that you are getting that as well.

[Mogli1476]

Re: Help with Onkyo TX NR 838

Did you adjust every pot to 0, at first?
I'm guessing, that you will have to make these adjustments, one at a time, until you are done with all the channels.
You had two channels blown, right?
So, you HAVE TO measure every component, at those two channels.
If you are not sure about something, than compare the measurements with the neighbor channel.
In some spots(1-2), you will have some measurements, that keeps dropping as you measure, make sure that you are getting that as well.

Yes! I did it like you write. Adjusting all potis to 0 and the channel by channel to the needed values.
Now it seems that the Pre Amp Board is fixed for the first time. The only problem now is that the receiver turns off approx. 10-15 sec. after turning on.
But if i turn on the receiver after removing the Pre Amp Board it works and the receiver stays on.
In Debug Mode the receiver detects a voltage protection and is showing a "V" in the debug window.
Also the Voltage protection check stops before the wifi checks is ending the procedure.
There should be an error in the VOLH Port. The debug window shows 043 and after 10 sec. the value goes to 053 and more. Then the receiver turns off.
Which components or what error could be in the Pre Amp Zone which are necessary for the VOLH Port.
Thanks, Mike

[Mogli1476]

Re: Help with Onkyo TX NR 838

Yes! I did it like you write. Adjusting all potis to 0 and the channel by channel to the needed values.
Now it seems that the Pre Amp Board is fixed for the first time. The only problem now is that the receiver turns off approx. 10-15 sec. after turning on.
But if i turn on the receiver after removing the Pre Amp Board it works and the receiver stays on.
In Debug Mode the receiver detects a voltage protection and is showing a "V" in the debug window.
Also the Voltage protection check stops before the wifi checks is ending the procedure.
There should be an error in the VOLH Port. The debug window shows 043 and after 10 sec. the value goes to 053 and more. Then the receiver turns off.
Which components or what error could be in the Pre Amp Zone which are necessary for the VOLH Port.
Thanks, Mike

Today I get new findings in this case.
The Receiver shows the same symptoms then yesterday. After powering on it stays on and approx. 10 - 15sec. later the receiver shuts down.
In the diag Mode the error V (Voltage error) occurs. I think if the VOLH is rising from 043 to 053 so that the receiver wants to change from LOW over MID to HIGH state and therefore voltage is needed from 0,4 - 2,3volts.
But changing from LOW to MID let the receiver go in voltage protection mode.
I'm not sure what exactly the problem is but after all the receiver stays on and let me check step by step to find a solution.
Sometimes after turning on an go into debug mode the receiver stays on an shows NG error.
He is getting warm and warmer but i think this is normal heat during the running process.
Could this be a problem of the HDMI Board? Which voltages are needed for the running process?
For this test I adjusted all Bias potis to zero. DO i have to change this back to the values in the SM for working?
Best regards, Mike

[tibimakai]

Re: Help with Onkyo TX NR 838

i don't know what else can I help with, I'm not and expert.
I have repaired quite a few of the 6 and 5 series Onkyos, never an 8 series.
Always, when something it was wrong, I have missed one or more components.
After rechecking the components, I always found something that I have missed previously.
Did you test all the components, on the SL channel as well?

[Mogli1476]

Re: Help with Onkyo TX NR 838

i don't know what else can I help with, I'm not and expert.
I have repaired quite a few of the 6 and 5 series Onkyos, never an 8 series.
Always, when something it was wrong, I have missed one or more components.
After rechecking the components, I always found something that I have missed previously.
Did you test all the components, on the SL channel as well?

Yes! Me too! But a lot of experience is available. I'm not sure that the Pre Amp Board is responsible for the problem but I think so.
Today i disassembled the Pre Amp Board again to check all channels again and again. In hope to find another problem. DO you have an idea how to isolate one of the channels to restrict channel by channel?
Earlier I am using a DC voltmeter to apply a voltage to each channel. I was using 30V DC on Pin4 and Pin5 which is normally 64V but I want to check how the board is recognising.
I was measuring the Voltage on the TRIM channel (Pin9) and the Voltage was between 5-7V. Most of the channels with 30V input don't have any problem and stay for min. 10mins without problems.
But on channel C and SL the amps are rising and one resistor with 82ohms is getting very hot and was smoking. Immediately I stopped the Power supply. SO I think these both channels were responsible for the problem.
Tomorrow I will Check all parts again and change some things. Then I will test it again with the power source from the outside and if every channel holds this 30V I will assemble all and check the whole system.
Regards, Mike

[tibimakai]

Re: Help with Onkyo TX NR 838

Usually that 82 Ohm resistor goes bad. Sometimes the 30 Ohms, 220 Ohm, 2.4 Ohm, the capacitor next to the 82 Ohm, sometimes blows up. I'm at work, so I can't look up anything and I'm just talking as I remember. There are two (smallest) SMD transistors, on the bottom of the board(toward the pot) that used to go bad, with a SMD resistor next to it(820 OHM ?!).
I would say, when you are checking components, each measurement, do it on the L channel in parallel. That way, it is easier to spot, if something is bad.

[madan1]

Re: Help with Onkyo TX NR 838

... DO you have an idea how to isolate one of the channels to restrict channel by channel?

Remove the 2 ( or 4? ) final transistors of the channel, or if the design allows - stop the power supply of the channel.

[Mogli1476]

Re: Help with Onkyo TX NR 838

So i have news in this case ...

Found another burned small transistor Q4110 in the ASP Section and a resistor R4120 which was not good. After changing both parts the Receiver stays on and seems to work.

I could adjust the idle current of all channels to the values in the service manual. But after i started the debug mode the display shows NG (Not good). After 15mins of running i adjusted all channels again and it shows no problems.

But after a new debug run the receiver shows NG again before the Wifi check began.

5 mins. later i checked the idle current again and channel R shows a value of 0mV. I'm wondering that the receiver not shut down. turning the idle poti shows no affect.

After this i turned the receiver off and disassembled the PRE Amp Board again.

And now at this time i don't know how to continue to proceed. Anybody know this problem?

Thanks and best regards, Mogli

[tibimakai]

Re: Help with Onkyo TX NR 838

Now, you have some bad components, at the R channel.

[Mogli1476]

Re: Help with Onkyo TX NR 838

Now, you have some bad components, at the R channel.

Yes! That could be the reason for the fault but i checked all parts on the R Channel and found no error. And if the R Channel have some broken parts on it why there is nothing burned after turning on the receiver?

Is it possible that other parts, for example on the main board, were broken? Which areas do i have to check for a working R Channel?

Thanks, Mogli

[tibimakai]

Re: Help with Onkyo TX NR 838

On the mainboard, also could be some broken parts.
I'm not looking at a schematics, but usually there are one or two low value resistors(through hole), that could be damaged, as well around the final transistors.

[Mogli1476]

Re: Help with Onkyo TX NR 838

On the mainboard, also could be some broken parts.
I'm not looking at a schematics, but usually there are one or two low value resistors(through hole), that could be damaged, as well around the final transistors.

Hey guys, good News!

The Receiver is working now. I'm not sure why but after replacing the old final Transistors in the R channel with ones now both are broken again.
Now i installed 2 new TTA/TTC 0002 Transistors from Mouser.
They don't fit perfect but i drilled two new holes in the heatsink and put the to another Position.
I decided to use the bigger TTA/TTC because it's easier to get both from mouser.

After testing the main functions everything seems ok. The Receiver is getting hot and hotter but i think this is normal characteristic during use.

Idling adjustment is also working like it should.

But some thing seems a little strange ... After first turning on the Receiver i run through all the test modes in the SM but Test Mode 1-01 stops with NG before Wifi Test started. It seems that there is another small Problem but i don't know which because Wifi is working without Problems.

Does anybody have a solution for that or can explain what could be the Problem?

Regards, Mike

[tibimakai]

Re: Help with Onkyo TX NR 838

Congrats on the repair!!
I have never done those tests.

[madan1]

Re: Help with Onkyo TX NR 838

..

But some thing seems a little strange ... After first turning on the Receiver i run through all the test modes in the SM but Test Mode 1-01 stops with NG before Wifi Test started. It seems that there is another small Problem but i don't know which because Wifi is working without Problems.

Does anybody have a solution for that or can explain what could be the Problem?

Even if one channel of voltage-detection protector check is NG, Wi-Fi connection check doesn't begin... .AVR automatically tests in the following test sequence. And if it is all OK, Wi-Fi test will begin.
Test sequence
(FL+) → (FR-) → (C+) → (SL-) → (SR+) → (SBL-) → (SBR+)
3. If FL tube displays Wi-Fi check mode then voltage-detection protectors test will be completed.

So it looks like it does not pass the voltage-detection protectors test.

[Mogli1476]

Re: Help with Onkyo TX NR 838

So it looks like it does not pass the voltage-detection protectors test.

Yes! I saw these lines in the SM too but that don't help me. In this test mode the receiver switches all channels through (The relays were clicking) and after the last channel, I think SBR+, it shows Video detection OK and after that comes NG.
No WIFi test is starting and the test mode stays in loop. the clock is running but nothing happens.

There is also no Voltage error in the debug window so why should there a voltage protection. The receiver runs good all he time and show no errors.

But what i find out today is the behaviour of the idle adjustment. I'm not sure which values are responsible for the final adjustment. In step 1 the SM says adjust immediately after turning on to the following voltages ....

And in step 2 the SM says after warming up (4-6mins) adjust the pots again to the new, higher voltages.

Last time i adjusted after 15mins run to 9-11mV and to 6-8mV. Everything seems Ok. Today i measured again after turning on and the Voltages were raising very fast. So i'm not sure if this is ok. Today i adjusted again like the values in step 1. But after 15mins run the voltages in step 2 were not reached. I have between 2,5 and 4,5 mV in the channels.

Please help me ...

[madan1]

Re: Help with Onkyo TX NR 838

If you can not cover the values specified in both steps, then just use step 2.

By the way, have you done a factory reset after the repair?


p.s. Just checked the SM, use 9-11mV for all channels after 10 minute warm-up run without input signal and speakers attached. This should be good enough.

[tibimakai]

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.

[Mogli1476]

Re: Help with Onkyo TX NR 838

If you can not cover the values specified in both steps, then just use step 2.

By the way, have you done a factory reset after the repair?


p.s. Just checked the SM, use 9-11mV for all channels after 10 minute warm-up run without input signal and speakers attached. This should be good enough.

Do you mean pressing CBL/SAT + ON/Standby and then Clear appears on the screen? Yes! Thats what i did.

It's possible for me to adjust the pots after warm up to 9-11 mV. I will try this next time. Otherwise i think there is another problem with the main Receiver. Today i removes the Pre AMP Board and turn on the Receiver to start the test modes again.

And whats happened? The same behaviour than with the Pre AMP Board installed. I tried to ran the idling test (Test 1-01) and the same error occurs on the display.
That means there is no problem with the Pre AMP Board but also with other parts within the receiver.

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?

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

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