ONKYO TX-NR807 receiver up in smoke

Thread Starter

Keellyy78

Joined Dec 27, 2023
18
What are you doing wrong?

View attachment 311800

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.
I was pushing hard. I had no problem getting the solder off the first time but when I tried to clean it up better I struggled trying to heat it up.
I’m using the proper iron.
does speaker wire substitute for wick.
 

Thread Starter

Keellyy78

Joined Dec 27, 2023
18
A light dimmer is an excellent idea for my bigger iron. I going to use that for my wood burning one also.

Thank you very much
 

MrChips

Joined Oct 2, 2009
31,076
If you are going to do some serious rework on a PCB which is what you are into right now, then it helps to have the right tools to do the job right.

1) A temperature controlled soldering station with properly sized tip, 1/16" for normal work, 1/32" for SMD.

Hakko soldering iron.jpg

2) 60/40 rosin core solder

Kester solder.jpg

3) Rosin flux pen
Rosin flux pen.jpg

4) Solder sucker

1704645147435.png

5) Solder wick

1704645231254.png
 

Thread Starter

Keellyy78

Joined Dec 27, 2023
18
Still trying to fix my f$&$ up. Every time I think I got it fixed it shorts again.
It looks like sh&$.
Here is where I’m at still. Since I did a shitty job removing components I’m paying for it now. The 3 hole’s for the transistors are randomly shorting. I turn the power on, all is good, put board back together same problem.
now I’m mad at myself so I cut a hole in the bottom of the case. Now I can test without having to put back together.

I was now thinking that it might be something else, so I did the exact same thing clean the holes out. I see where the board wires have now burnt learning lesson fast turn on the receiver with nothing plugged in receiver is upside down let’s sit for five minutes no smoke no problems. Flip the machine over turn power on again start testing. The DC voltage to the speakers terminals starts sparking again in those holes.

Here’s the dumb question? Obviously you need a ground where is the ground. to have a short it has to be grounded out correct
 

Thread Starter

Keellyy78

Joined Dec 27, 2023
18
I know my eyes are bad but I can’t see where it is touching. I messed with it so much that I melted the ring
I’ll show you the pictures of the small transistor holes that spark. First will be surround L then L channel image.jpgimage.jpg
 

Thread Starter

Keellyy78

Joined Dec 27, 2023
18
Anyone??? . Just can’t move forward without knowing what is wrong still.
I have no problem with criticism and doubt of my ability. Just don’t need to be rude. I know I have f???ed up. Most of you can’t build your ideas or dreams without construction or welding.
if you want help with that just PM me.
 

djsfantasi

Joined Apr 11, 2010
9,186
Anyone??? . Just can’t move forward without knowing what is wrong still.
I have no problem with criticism and doubt of my ability. Just don’t need to be rude. I know I have f???ed up. Most of you can’t build your ideas or dreams without construction or welding.
if you want help with that just PM me.
a couple places there appears to be grey lines connecting pads. Could be carbon trapped in flux remains forming a resistor

lots of flux left on the board. Too much can be conductive. Clean it off with alcohol, sn old toothbrush and a rag.
 

Thread Starter

Keellyy78

Joined Dec 27, 2023
18
a couple places there appears to be grey lines connecting pads. Could be carbon trapped in flux remains forming a resistor

lots of flux left on the board. Too much can be conductive. Clean it off with alcohol, sn old toothbrush and a rag.
You are correct about the flux. I didn’t realize that it would be conducive. I used lots of the asid flux and never really cleaned it off.
I will try that right now ( have to dismantle again but cutting a hole in the bottom of the case this time. ) will message in a few hours.
 

Thread Starter

Keellyy78

Joined Dec 27, 2023
18
a couple places there appears to be grey lines connecting pads. Could be carbon trapped in flux remains forming a resistor

lots of flux left on the board. Too much can be conductive. Clean it off with alcohol, sn old toothbrush and a rag.
Long story short. I zip cut a small hole in bottom of case (I will weld it back together and never tell it happened )
you are 100% correct about the flux. No sparky spark anymore. I did pop something (I smell it) but receiver is out of protection mode but worried to leave on. I’ve only left for 2min.
I’m going to move forward with MRCHIPS instruction to test the v_ (I’m sure this is multimeter symbol) for volts on the individual channels. Red to red back to back and make sure to pay attention weather it’s a + number or ~ number
 
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