Insignia NS-50L240A13 power supply problem

SLK001

Joined Nov 29, 2011
1,549
I thought I was pretty competent reading wiring diagrams until I saw the layout for this power board. It's an entirely different animal!
And it is a single sided board, no less. You don't have a capacitor tester, but charge the cap to as high a voltage as you can and see how long it takes to discharge. For instance, charge to 50VDC, then measure the voltage. Wait 5 minutes and measure it again.

And to clarify, everything is back on the board, except the big cap, and the fuse blowing stopped?
 

Thread Starter

landon3185

Joined Apr 29, 2016
16
And to clarify, everything is back on the board, except the big cap, and the fuse blowing stopped?
Yes, the only thing removed is the big cap and the fuse no longer blows when power is applied.

I will charge and measure the cap when I get home tonight.
 

Thread Starter

landon3185

Joined Apr 29, 2016
16
The new cap came in. I installed it and powered it up and all seemed good. I installed the board back in the tv and plugged it in and about 30 seconds later the new cap exploded. I think I'm throwing in the towel on this project.
 

SLK001

Joined Nov 29, 2011
1,549
The new cap came in. I installed it and powered it up and all seemed good. I installed the board back in the tv and plugged it in and about 30 seconds later the new cap exploded. I think I'm throwing in the towel on this project.
Well, at least it didn't immediately blow the fuse. What is the pedigree of your replacement cap? If you don't know, it might be cheap crap from China. Always get quality caps for the high voltage stuff. If you did indeed install the cap correctly, then it was probably mislabeled (deliberately) Chinese counterfeits.
 

Thread Starter

landon3185

Joined Apr 29, 2016
16
Well, at least it didn't immediately blow the fuse. What is the pedigree of your replacement cap? If you don't know, it might be cheap crap from China. Always get quality caps for the high voltage stuff. If you did indeed install the cap correctly, then it was probably mislabeled (deliberately) Chinese counterfeits.
I ordered it from mouser.com. I entered the specs and measurements from the cap I removed and the one that came in looked exactly the same except for the brand name. I've had good luck with mouser buying joystick sensors to repair Xbox one controllers. Are they a good source for electronic parts? Does it sound like it may have just been a bad cap?
 

SLK001

Joined Nov 29, 2011
1,549
Mouser is a good source. The only reasons caps blow like that is a) installed backwards, and b) operation over the stated voltage rating.

What was the exact cap that you ordered?
 

Thread Starter

landon3185

Joined Apr 29, 2016
16
Mouser is a good source. The only reasons caps blow like that is a) installed backwards, and b) operation over the stated voltage rating.

What was the exact cap that you ordered?
647-LGU2E681MELC
MFG Part No:LGU2E681MELC
LGU2E681MELC
Nichicon Aluminum Electrolytic Capacitors - Snap In

^thats what's on my order from mouser.

In the photos the nichicon on the left is the new one that popped.

Is there any way to check the polarity other than the markings?
 

Attachments

SLK001

Joined Nov 29, 2011
1,549
Is there any way to check the polarity other than the markings?
No. You HAVE to believe the markings. If you are 100% positive that you put the cap in correctly, then call Mouser and ask about their confidence that their part was genuine. Unless you plugged your set into a 220V outlet, there is NO WAY that you exceeded 170V on the cap.
 

SLK001

Joined Nov 29, 2011
1,549
Test the location's ground by putting a meter on the (-) terminal of the bridge and finding out which hole is the ground hole.
 
Top