Failed DC transformer. Interesting for a tear down?

[Matt-]

Hey all,

I'm a long time lover of the channel and have had an electronics failure that I thought may be interesting for a tear down.  It's a standard 240vAC -> 12vDC wall wart which has suddenly decided to start outputting double its rated voltage.

Is this a common failure or is it worth sending in to Dave for some surgery?

TIA.

[Ian.M]

Sounds like the feedback circuit has failed and is so crappy that there is no other limiting circuit so the  primary side switched mode controller is running flat-out.    IMHO its of very little interest as although its not a very common failure mode, one cracked track or open-circuit resistor is enough to cause it.

Why not tear it down yourself and post about it here?  If you don't feel up to doing a video, good photos and text are IMHO actually preferable as they take a lot less time to look at, and are easier to study in detail.  If you do do a video, *KEEP* *IT* *SHORT*' - 5 minutes max.

[Wan Huang Luo]

I agree with Ian. Dave's a busy man right now, with two young kids and moving his lab. You have the time and resources to do this yourself and share your findings. Why don't you open it up and see what you find?

[Jebnor]

Is this a common failure or is it worth sending in to Dave for some surgery?

Yes;
No. 
In that order.

This is one of those where taking it apart yourself is safe (No plugged in of course)  and you can see how it works.  Look up "wall wart circuit" in your favourite search engine of choice and see if you can determine which circuit yours is using.

Enjoy,
Jeb

[tpowell1830]

Hey all,

I'm a long time lover of the channel and have had an electronics failure that I thought may be interesting for a tear down.  It's a standard 240vAC -> 12vDC wall wart which has suddenly decided to start outputting double its rated voltage.

Is this a common failure or is it worth sending in to Dave for some surgery?

TIA.

Hi Matt, welcome to the forum. I do not recommend sending this to Dave, however, if you wish to tear it apart and try to understand it, Big Clive does this on his channel very often and reverse engineers these types of supplies all the time.

Check him out here:

https://www.youtube.com/user/bigclivedotcom/videos


Hope this helps...