Onkyo tx-nr414 shutting off after few seconds

[Tamo Neko]

Re: Onkyo tx-nr414 shutting off after few seconds

Dead end, checked everything I could think off still no luck...
About that short I do think it comes from secondary 0 so I think that is normal too...

[Tamo Neko]

Re: Onkyo tx-nr414 shutting off after few seconds

And yes replacing output transistors did not help either...

[keeney123]

Re: Onkyo tx-nr414 shutting off after few seconds

And yes replacing output transistors did not help either...

As a last resort you could charge a large oil fill cap up with 600 volts. Put it across the short and see if anything pops. It will not be on long enough to destroy anything else and all the current should go through the short.

[Tamo Neko]

Re: Onkyo tx-nr414 shutting off after few seconds

As a last resort you could charge a large oil fill cap up with 600 volts. Put it across the short and see if anything pops. It will not be on long enough to destroy anything else and all the current should go through the short.

That is something new...Thanks for sharing

[Tamo Neko]

Re: Onkyo tx-nr414 shutting off after few seconds

I see now that I reported c6402 which was not the capacitor in question, I was was way too tired of this unit...
I can see now from schematic that c6402 is one of two big capacitors...
C6403 and c6404 are giving a short, but as they are connected directly across secondary I was measuring in between transformer...

[Tamo Neko]

Re: Onkyo tx-nr414 shutting off after few seconds

Can it be mains voltage causing this fault? I do have around 250vac mains?
I will try to lower it on 230v as declared...

[keeney123]

Re: Onkyo tx-nr414 shutting off after few seconds

Can it be mains voltage causing this fault? I do have around 250vac mains?
I will try to lower it on 230v as declared...

Highly unlikely as the transformer isolates the main from the 56 volt DC. What I was thinking is if you have a power supply you could use that supply. You would put a resistor in series with the -56 v line. This resistor would be between your power supply and the board. This is so the power supply will not shut down. Remember the 56 v in negative so if you have only a positive supply you will need to connect the black lead of the supply to the -56v line and the red lead to ground. If your supply does not have a current read as you increase the voltage than you would also need to put a amp meter in series. You can then use your thermal camera or just touch the components to see if one is heating up more than normal.
The only other way I know of is to trace the -56v line and see where it goes. Then make cuts in the line. First cut to separate half of the circuit. Then find out which half the short remains. Then cut that section in half. So on and so forth until you find the short.

[Tamo Neko]

Re: Onkyo tx-nr414 shutting off after few seconds

Test mode on Onkyo does engage those lines but I could not see with thermal camera anything strange...
This method that you talk about is good for the more detailed view on this board - especialy underside...
You know what I am thinking?
I might try to remove vprotect line and roll the dice...
I did not have free time today to continue on this unit...

[keeney123]

Re: Onkyo tx-nr414 shutting off after few seconds

Test mode on Onkyo does engage those lines but I could not see with thermal camera anything strange...
This method that you talk about is good for the more detailed view on this board - especialy underside...
You know what I am thinking?
I might try to remove vprotect line and roll the dice...
I did not have free time today to continue on this unit...

In the old days when we did not have the switching power supplies it was very easy to tell when something shorted out. Once one knew what shorted it was easy to tell if the components associated with it cause it or not. Back then it was easier to trace lines because they were bigger. If todays engineers wanted to help the technicians they would build the protection circuits within each chip with the ability to disconnect from the input and output lines and then issue a flag to report it to the processor.

[Tamo Neko]

Re: Onkyo tx-nr414 shutting off after few seconds

In the old days when we did not have the switching power supplies it was very easy to tell when something shorted out. Once one knew what shorted it was easy to tell if the components associated with it cause it or not. Back then it was easier to trace lines because they were bigger. If todays engineers wanted to help the technicians they would build the protection circuits within each chip with the ability to disconnect from the input and output lines and then issue a flag to report it to the processor.

Yes I agree, and todays manufactures have a task to disable the unit after warranty period in which ever manner is possible.
There is a world legislation coming up which obligates them to put a index of ease of serviceability and expected years of usage (don't mark my words but something like that).

And we all know why is that legislation so necessary

[Tamo Neko]

Re: Onkyo tx-nr414 shutting off after few seconds

There are 28 volts present at main caps instead of 56v...?

[Tamo Neko]

Re: Onkyo tx-nr414 shutting off after few seconds

OK sorry everything is ok, but unit still shuts off after few seconds...
Forget about faults I reported even cause off shut off...
It seems to me a lot non intuitive servicing this...
What I am for sure getting is reason for shut off is "other" or as in the manual says "-"
I will try re-flashing as there is nothing more I could think off right now...

I will recheck idle current before reflashing...

[Tamo Neko]

Re: Onkyo tx-nr414 shutting off after few seconds

Idling ok, hmmm...
Firmware ok...
Voltages seem fine...
Could not find odd value on this unit...

[keeney123]

Re: Onkyo tx-nr414 shutting off after few seconds

Idling ok, hmmm...
Firmware ok...
Voltages seem fine...
Could not find odd value on this unit...

Do you still have the 0.6 Ohms to gnd. on the -56 Vout line? If so I would look at the output of the power transistors. Page 5 of the manual you have a 12 volt trigger control that seems to short the unused outputs to Gnd to eliminate noise on those lines. I am wondering if one of those transistors are not working correctly of the 12Volt trigger is not selecting them correctly.

[Tamo Neko]

Re: Onkyo tx-nr414 shutting off after few seconds

Ok I will check that, but I am currently working on fixing a bias voltage difference on one of the channels. Surround left to be exact.

[Tamo Neko]

Re: Onkyo tx-nr414 shutting off after few seconds

No shorts at output...
Checked preamplifier board and all is ok...
There is still bias diference of 100mv.
Now the question is, would that trigger protection?

[Tamo Neko]

Re: Onkyo tx-nr414 shutting off after few seconds

To explain better post above, voltage to ground is about 250mv from adjusting idle current points...and that is on surround left...

[Tamo Neko]

Re: Onkyo tx-nr414 shutting off after few seconds

Unit shuts off immediately when in diag mode button GAME is pressed...
Would that point to some components?

[keeney123]

Re: Onkyo tx-nr414 shutting off after few seconds

Unit shuts off immediately when in diag mode button GAME is pressed...
Would that point to some components?

If you look at the pdf service manual and do a find from the upper right hand. Then put in the word game in the find box you will see all the points that game is associated with.

In the user manual below, there seems to be an input selector for games in the user manual it is 9 on page 10. There is also a game button on the remote which deals with listening mode. First one would have to differentiate which one are you talking about the input selector of the mode of listening on the remote.

[Tamo Neko]

Re: Onkyo tx-nr414 shutting off after few seconds

If you look at the pdf service manual and do a find from the upper right hand. Then put in the word game in the find box you will see all the points that game is associated with.

In the user manual below, there seems to be an input selector for games in the user manual it is 9 on page 10. There is also a game button on the remote which deals with listening mode. First one would have to differentiate which one are you talking about the input selector of the mode of listening on the remote.

Yes, sorry. I mean page 21 that can be found in attached tx-nr 535 pdf.
That is OPERATION CHECK 8 - Auto Measurement mode whichever one comes available first and that is 4-00 (or 4.30 if you try to enter it from 5.00) on this page -....