Onkyo TX-NR616 won't stay powered on

[tibimakai]

Re: Onkyo TX-NR616 won't stay powered on

Yes I can confirm now that there is no video on any of the video outputs.
I have tried HDMI, component and composite. TV recognizes that there is something connected at that output, but there is no signal found.
The audio is working.

[tibimakai]

Re: Onkyo TX-NR616 won't stay powered on

I have re installed the finals, placed two multimeters at the bases and turned it on.
Did not replaced the emitter resistors.
I have turned it on briefly and I have seen around 0.5Vs and then I turned it on and left it on.
To my surprise, it was working and those voltages were exactly the same, 0.59V.
So, the unit it's working. The only problem I'm having, is that I can't get video signal to my monitor. I will have to try it out on a TV.
Thank you very much for all your amazing help.
I still don't know what caused the blow, but the final result matters.

[rievax_60]

Re: Onkyo TX-NR616 won't stay powered on

The bases shouldn't have the same voltage, as the good channel? It doesn't seem balanced to me.

The feedback loop acts to control the point that its sensing, to zero volts.
there is no true center point to connect to in the output's driver stage.
It is the voltage difference at the finals' Bases that's more important.

[rievax_60]

Re: Onkyo TX-NR616 won't stay powered on

These resistors should have a high wattage?

High wattage would be best but maybe difficult to fit. Small resistors will be ok while there is no faults. The small resistors should also allow the amp to be run at very low volume into speakers, too loud will burn them out.
The main reason is to protect the finals while one last check is done on the bias.
Have you noticed and design differences compared to the schematic? Is R5476 really 82 ohms?

[tibimakai]

Re: Onkyo TX-NR616 won't stay powered on

Did you check the bias transistors for cracked solder joints?

Not yet, I have to take apart the whole receiver for that.
Next step, it will be that and re-installing the finals and maybe those emitter resistors.

[tibimakai]

Re: Onkyo TX-NR616 won't stay powered on

All you can do now is fit the finals. If you want to take one more precaution, temporarily replace the emitter resistors with something from 10 to 100 ohms, then take some more voltage readings.
Did you check the bias transistors for cracked solder joints?

These resistors should have a high wattage?

[tibimakai]

Re: Onkyo TX-NR616 won't stay powered on

The bases shouldn't have the same voltage, as the good channel? It doesn't seem balanced to me.

[rievax_60]

Re: Onkyo TX-NR616 won't stay powered on

I just spotted something that bothers me. If the bias adj pot, R5445, develops poor wiper contact, the bias voltage will abruptly increase. Bias circuits are usually designed to be fail safe. If the pot fails, the bias reduces.
This can be checked by measuring between the final bases while adjusting the bias pot. The voltage should vary smoothly, not be jumpy. Leave it set to 1v for now.
A drop lite oil like sewing machine oil makes pots work better.

[rievax_60]

Re: Onkyo TX-NR616 won't stay powered on

At a good channel, at both bases similar to Q5436/Q5446 I'm, getting exactly +/-1.24V.
At the same channel at the final's bases, I'm getting exactly +/-0.53V.
That channel is perfectly balanced.
I have removed the link and the voltages at the Q5446/Q5436 bases and the final's bases jump up to around 20-24V.
Not good.

When you remove the link, the feedback path becomes open, look where R5036 goes to.
It all should be ok when you fit the finals. But we still dont know why the last pair failed. All you can do now is fit the finals. If you want to take one more precaution, temporarily replace the emitter resistors with something from 10 to 100 ohms, then take some more voltage readings.
Did you check the bias transistors for cracked solder joints?

[tibimakai]

Re: Onkyo TX-NR616 won't stay powered on

At a good channel, at both bases similar to Q5436/Q5446 I'm, getting exactly +/-1.24V.
At the same channel at the final's bases, I'm getting exactly +/-0.53V.
That channel is perfectly balanced.
I have removed the link and the voltages at the Q5446/Q5436 bases and the final's bases jump up to around 20-24V.
Not good.

[tibimakai]

Re: Onkyo TX-NR616 won't stay powered on

At the Q6066 base is -0.001V and at the Q6056 there is 1.2V with the resistor removed and link left there.
The other voltages did not change.(-0.64V and the 1.8V)
I will continue later.

[rievax_60]

Re: Onkyo TX-NR616 won't stay powered on

That is -.064V you are right, forgot to put it there.
I didn't had to much time today, to measure at the finals.
I have to solder two wires at pin#2 and #3 at the connector, to be able to measure those base voltages.
I still leave the link and resistor in place, right?
I hope I didn't do something stupid and that is why it blew those parts.
I appreciate a lot your help. I'm new in this field. I have repaired three Harman Kardon AVR1700 with Tom's help an Onkyo with your help(transformer fuse) and now this Onkyo.
I have picked up a Yamaha HTR-4065 and tomorrow I'm picking up a Pioneer VSX1022-k.
The Yamaha seems dead, only the power button blinks a couple of times and even that blinking goes away.
Transformer doesn't get 120V. I will start another thread with these receivers.

Leave the link in for now.
Remove the 1K resistor, its job was to prevent the bias voltage going too high if there was a fault in the bias circuit. Confirm that the bias voltage has not changed by much.
There still could be an intermittent fault in the bias circuit. Check Q6006 , Q5446 and associated components for fractured solder joints.
Ill wait until you have measured the bias voltage on the good channel then you will have to fit the finals. A precaution can be taken by temporarily replacing the emitter resistor with something higher in value to protect the finals incase there is still something wrong. The link will need to be removed.

[tibimakai]

Re: Onkyo TX-NR616 won't stay powered on

That is -.064V you are right, forgot to put it there.
I didn't had to much time today, to measure at the finals.
I have to solder two wires at pin#2 and #3 at the connector, to be able to measure those base voltages.
I still leave the link and resistor in place, right?
I hope I didn't do something stupid and that is why it blew those parts.
I appreciate a lot your help. I'm new in this field. I have repaired three Harman Kardon AVR1700 with Tom's help an Onkyo with your help(transformer fuse) and now this Onkyo.
I have picked up a Yamaha HTR-4065 and tomorrow I'm picking up a Pioneer VSX1022-k.
The Yamaha seems dead, only the power button blinks a couple of times and even that blinking goes away.
Transformer doesn't get 120V. I will start another thread with these receivers.

[rievax_60]

Re: Onkyo TX-NR616 won't stay powered on

OK, at the Q5436 base I have 1.8V and the other only 0.64V.
I'm not sure how to measure another channel? As is, or I have to place the same link with the resistor there also?

Those voltages would be close to correct if the 0.64 was really -0.64v
I would like to have seen the voltages that would be going to the Bases of the finals also.
So far I dont see a strong reason for the last set of finals failing.
The 2.4v between the Bases of Q5446 and Q5436 is higher than the 2v I calculate it should be.
Measure this voltage on the good channel. There is no need to modify anything on the good channel

[tibimakai]

Re: Onkyo TX-NR616 won't stay powered on

OK, at the Q5436 base I have 1.8V and the other only 0.64V.
I'm not sure how to measure another channel? As is, or I have to place the same link with the resistor there also?

[rievax_60]

Re: Onkyo TX-NR616 won't stay powered on

If the voltages at the bases of Q5446 and Q5436 look ok. The next thing to measure are the voltages that would be applied to the bases of the finals.

[rievax_60]

Re: Onkyo TX-NR616 won't stay powered on

What we have discussed here.
Today I had a little bit of time and I did what you have told me. Removed the link and added a 1k resistor.
I wasn't sure about the other link, so I have removed it. Should I put it back?

Yes, you should have left the other link in.

[tibimakai]

Re: Onkyo TX-NR616 won't stay powered on

What we have discussed here.
Today I had a little bit of time and I did what you have told me. Removed the link and added a 1k resistor.
I wasn't sure about the other link, so I have removed it. Should I put it back?

[rievax_60]

Re: Onkyo TX-NR616 won't stay powered on

I got you to fit two links originally. What have you done since?

[tibimakai]

Re: Onkyo TX-NR616 won't stay powered on

Yes, I have removed it and soldered in that 1K resistor.
Should I solder back that link?