ONKYO TX-NR807 receiver up in smoke

Thread Starter

Keellyy78

Joined Dec 27, 2023
18
Hello everyone I’m a new member with some knowledge of electrical, but the wrong kind.

I have a onkyo tx-nr807 receiver that I was playing the music way loud a few years ago and it turned off so I came back inside and turned it back on and as I walked away, it was shorting out sparks everywhere. I unplugged it weeks later it took it apart, took the screw out of where it shorted in the transistor? I believe and plugged it back in. Turned it back on and poof. A capacitor went . I left it and forgot about it.

Now I am off work for a long time because of an injury and I’ve taken it apart but I’m at a point where I need to order parts or figure out what to do and I’m looking for a little advice or lead me in the right direction.
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Hi everyone I'm new here and would like some assistance. I have a Nokia TX-nr 807 home stereo receiver. I was blasting the music loud and frequently and it shut off one day I went inside and turned back on and as I walked away it started smoking I unplugged

Years later I am now working on it and plugged it back in hit the power button and poof a capacitor went. I have managed to take it apart and have the boards out but I'm not sure what to buy. I'm a journeyman welder but I do not understand electrical drawings but I do know the obvious but can't find the transducer part. Any help would be appreciated this is just a Time killer for me so it doesn't matter how long I take on it because I'm off work for a long time. And since it doesn't work anyways why not try. Thanks

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Hi everyone i’m new here. I’ve been playing around with my Pinocchio TX – NR 807 receiver that was sparking and smoking a few years ago.
Since I’ll be off work for a while I’m trying to repair it and I’ve managed to get pretty far but I’m at a point that I really don’t know what I’m doing.
Here’s what happened. Was blasting my music receiver, shut off because it was too hot I assume. Turned it back on few seconds later it was shorting out and sparking and smoking so I pulled the plug. Took it apart to see what was wrong . It looks like the transducer? Was melted took the screw out plug it back in turned on proof capacitor? Popped.

Now I’ve managed to take it all apart and have the board out. I want to try and fix it.(bored.)
I’m a journeyman welder but I don’t solder, much but I have a gun and solder. I’ll show as much pictures as possible and I appreciate it if anybody could steer me in the right direction.
Thanks

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Service manual here , https://elektrotanya.com/onkyo_tx-nr807_full.pdf/download.html

Snapshot of the power amplifier.

Screenshot_2023-12-27-14-55-42-951_com.adobe.reader.jpg
 

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MrChips

Joined Oct 2, 2009
30,939
Here are things you will need for starters to work on this repair.

1) soldering iron (about 25W-35W) - a soldering gun is too hot and will destroy the circuit board
2) rosin core solder
3) solder wick and/or solder sucker
4) DMM (digital multimeter)
5) You might have to build a test lamp circuit.

Step 1
Disconnect all loudspeakers.

Step 2
Remove both power transistors at the bad output channel. (Q6053 and Q6063 or similar.)
Remove and replace the blown capacitor. (C6023 or similar.)

Step 3
Power On the unit and see/smell what happens.

ONKYO TX-NR807 amplifier.jpg
 

Thread Starter

Keellyy78

Joined Dec 27, 2023
18
So I removed L surround and installed the 4 transistor to L and swapped the cap out also.
It doesn’t go to protection mode right away but I smelled something burning. Unplugged it and removed the board again.
I know I didn’t do a good job but I tried my best with what I have. Here is a picture.
What would be my next step image.jpg
 

MrChips

Joined Oct 2, 2009
30,939
So I removed L surround and installed the 4 transistor to L and swapped the cap out also.
It doesn’t go to protection mode right away but I smelled something burning. Unplugged it and removed the board again.
I know I didn’t do a good job but I tried my best with what I have. Here is a picture.
What would be my next step
What transistors did you install?

I said, remove the transistors. I did not say to replace the transistors.
 

MrChips

Joined Oct 2, 2009
30,939
They are all the same #. One side and same on the other side
I just matched them up correctly
That is not the point.

The first thing we do when the power transistors go is to remove both transistors and keep them off.
Then we have to hunt around and find out what caused the transistors to blow, not add more transistors and watch them blow again.
 

Thread Starter

Keellyy78

Joined Dec 27, 2023
18
That is not the point.

The first thing we do when the power transistors go is to remove both transistors and keep them off.
Then we have to hunt around and find out what caused the transistors to blow, not add more transistors and watch them blow again.
Ok I apologize. I realized that you’re trying to help and I can’t do this without help.
If you’re still willing to help I will follow your instructions to a tee
 

MrChips

Joined Oct 2, 2009
30,939
Can you please identify which capacitor was blown (i.e. PCB designation number, for example, C6023)?

Also which transistors were blown and removed? (for example, Q6053, Q6063).
What transistors did you removed and moved to what new location?
 

Thread Starter

Keellyy78

Joined Dec 27, 2023
18
Can you please identify which capacitor was blown (i.e. PCB designation number, for example, C6023)?

Also which transistors were blown and removed? (for example, Q6053, Q6063).
What transistors did you removed and moved to what new location?
Here is exactly what I did in layman’s terms.
original problem left speaker right transistor, Q6060 and capacitor C620 we’re obviously blowing.

So now what I removed from the left speaker was the big transistor q6060 and capacitor, C6020 and the small transistors a1930 and C5171

I exchange them with surround left big transistor Q6063 , Capacitor C6023, and small transistor a1930 and C5171 Those are the numbers on the transistor itself.

The small transistor on the board numbers are left side Q6100 and Q6110. Surround left Q6131 and Q6131.

did not replace any parts on the surround left, left them blank.

I know longer in protection mode right away. It does turn on, but I think I can smell something so I shut it off right away.
 

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Thread Starter

Keellyy78

Joined Dec 27, 2023
18
When I tested all the transistors my voltmeter bounces all over the place and I don’t get accurate readings. It seems to keep rising or bounces around. This is my tester and what I’m using
 

Attachments

MrChips

Joined Oct 2, 2009
30,939
Remove the four transistors that you have moved around.
Now you should have a total of eight transistors off the unit.

Get yourself a sheet of heavy stock paper or cardboard and some masking tape.
Tape the transistors on the cardboard and label where they came from.
I am assuming that the transistors are Q6100, Q6110, Q6050, Q6060 from the L section
and Q6103, Q6113, Q6053, Q6063 from the SL section.

Leave the capacitor where it is. Which one is it, C6020 or C6023?

We now have two amplifier sections that are non-functional, L and SL.

Our first goal is to stop the smoking.

ONKYO TX-NR807 L channel.jpg

ONKYO TX-NR807 amplifier.jpg
 

Thread Starter

Keellyy78

Joined Dec 27, 2023
18
Remove the four transistors that you have moved around.
Now you should have a total of eight transistors off the unit.

Get yourself a sheet of heavy stock paper or cardboard and some masking tape.
Tape the transistors on the cardboard and label where they came from.
I am assuming that the transistors are Q6100, Q6110, Q6050, Q6060 from the L section
and Q6103, Q6113, Q6053, Q6063 from the SL section.

Leave the capacitor where it is. Which one is it, C6020 or C6023?

We now have two amplifier sections that are non-functional, L and SL.

Our first goal is to stop the smoking.

View attachment 311427

View attachment 311428
Ok I followed your instructions and here’s the drawing image.jpg
 

MrChips

Joined Oct 2, 2009
30,939
That's good.
Now, disconnect all loudspeakers. Do not connect any loudspeakers until I ask you to do so.

Power on the unit and look and smell closely. If you see any smoke, try to pinpoint which component is smoking.
If the unit turns on ok with no smoking and comes out of protection mode, you can move on to the next step.

Get your test meter and set it to DC Volts measurement.

Measure the voltage at the RED and BLACK terminals of all the loudspeaker channel outputs, using the red meter lead connected to the RED terminal, and the black meter lead connected to the BLACK terminal.

Write down your measurements, making sure to show + or - readings. If you forget to write down + sign you will have to repeat the measurement.

After this, I will ask you tomorrow to take some more voltage measurements on the board itself.
 

Thread Starter

Keellyy78

Joined Dec 27, 2023
18
That's good.
Now, disconnect all loudspeakers. Do not connect any loudspeakers until I ask you to do so.

Power on the unit and look and smell closely. If you see any smoke, try to pinpoint which component is smoking.
If the unit turns on ok with no smoking and comes out of protection mode, you can move on to the next step.

Get your test meter and set it to DC Volts measurement.

Measure the voltage at the RED and BLACK terminals of all the loudspeaker channel outputs, using the red meter lead connected to the RED terminal, and the black meter lead connected to the BLACK terminal.

Write down your measurements, making sure to show + or - readings. If you forget to write down + sign you will have to repeat the measurement.

After this, I will ask you tomorrow to take some more voltage measurements on the board itself.
It’s no longer in protection but when I turn it on transistor holes of q6100 the L small one is sparking Only when I turn it on. No problem with it just plugged in
image.jpg
 

MrChips

Joined Oct 2, 2009
30,939
Re: Holes at Q6100 and small one sparking.

Either there are solder bridges on the bottom side or Q6030/Q6040 are shorting.
Remove both Q6030 and Q6040 (not the one in the middle). Make sure you note which one is removed from where (the transistors are different and cannot be interchanged).


ONKYO TX-NR807 L channel circuit diagram.jpg

View from component side (top view).
ONKYO TX-NR807 L channel top view.jpg

View from solder side (bottom view)
ONKYO TX-NR807 L channel solder side view.jpg
 

Thread Starter

Keellyy78

Joined Dec 27, 2023
18
Ok I’ll try cleaning holes first. If the same then I’ll remove the 2 like you said. The next time I gotta pull this apart, I’ve gotta cut a hole in the bottom. It’s very difficult to take every board in and out.
 

Thread Starter

Keellyy78

Joined Dec 27, 2023
18
Now very light sparking in those holes and the other ones (small transistor). I removed both Q6030 and 40 on L and SL.
I know that it takes lots of practice and patience to solder and remove but………WTF am I doing wrong. Constructive criticism please

Mod: Please, no expletives.
 

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MrChips

Joined Oct 2, 2009
30,939
Now very light sparking in those holes and the other ones (small transistor). I removed both Q6030 and 40 on L and SL.
I know that it takes lots of practice and patience to solder and remove but………WTF am I doing wrong. Constructive criticism please
There should be no sparks anywhere on the circuit board.

Why did you remove transistors on SL section? I did not ask you to do that.
 

MrChips

Joined Oct 2, 2009
30,939
but………WTF am I doing wrong. Constructive criticism please
What are you doing wrong?

ONKYO TX-NR807 PCB solder bridges.jpg

1) Your soldering iron is too hot. You either need a temperature controlled soldering station or you should put a light dimmer control on your iron.

2) You are using too much pressure or force on the PCB pads. Too much heat and pressure will lift the copper pads and traces off the board. In order to remove a component, add some more rosin core tin/lead solder to the joint first. This allows the joint to take up the heat better, especially if the original solder used is lead free. Once the solder is melted, use a solder sucker to suck up the solder. While the pad and leg is still hot, move the component leg around so that it breaks free from the hole.

(Also while the joint is still hot, try to straighten the component leg so that it sits vertically in the center of the hole. This will make it easier to break free from the hole and to extract the component.)

Then work on the other legs until you can lift the transistor freely from the board. If we don't want to save the component, it is easier to clip the component away from the leg, while leaving sufficient leg that you can grab with needle nose pliers.

3) You now have solder bridges between traces. This will cause shorts and sparking. Get some solder wick and clean up all around the pads and traces.
 
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