EEVblog 1423 - Magic Repair Smoke

[EEVblog]

Dave released the magic smoke during a repair!
Brain was not engaged...

00:00 - Alien LED driver
01:34 - New microscope measurment setup!
02:46 - Teardown
07-45 - Brown Black Burnt
09:31 - This sucks!
16:08 - BANG!
18:49 - It seemed reasonable at the time...
19:41 - Reverse Engineering

[Neilm]

Humm - Trap for old players there... I wonder how many other old players have made an assumption and got things totally wrong (I know I have)

I would have been weary of using it even if it had been repaired - if the resistor got so hot it delamminated the PCB who knows what else had been stressed / damaged due to it.

At least you gave it a Viking funeral

[NiHaoMike]

Looks like confirmation bias strikes again.

[ssander]

Dave,

In your video Astable Aliens, you had a potential known good reference i.e. another light.   

[sean0118]

I think there must have been something else wrong with it anyway, maybe the 180k was short putting the full rectified voltage across the failed resistor?

This was a much better option than putting it in the bin first, if only Dave setup a slow motion camera. I wouldn't mind if he plugged it in a second time actually. 


Also, really surprised there doesn't seem to be an input fuse, unless those input resistors are the fusible type?

[golden_labels]

Put a tape over the button while filming scenes of devices being powered on!

[BrokenYugo]

Also, really surprised there doesn't seem to be an input fuse, unless those input resistors are the fusible type?

I was under the impression that fusible resistors are flameproof...

[Kleinstein]

With the input resisors there is no real need for another fuse.
Chances are the one small resistor under the shlieve that Dave first considered a fuse may be a fusibel resistors.  However the other 4 were faster.

[thm_w]

Dave,

In your video Astable Aliens, you had a potential known good reference i.e. another light.   

Probably too much work to take it down, but that would have been ideal.

With the input resisors there is no real need for another fuse.
Chances are the one small resistor under the shlieve that Dave first considered a fuse may be a fusibel resistors.  However the other 4 were faster.

Thats what he said, the value was very low, 0.1R.

[jonovid]

  holy moly even yt blogger Big Clive knows the value of reverse engineering a two layer pcb ,   
looks like too much in a hurry to get the video out & uploaded. when more time is needed to get the job completed.
the need to keep it always live! can be a trap.  for all players.
Big Clive has a saying when not prepared or unsure    one moment please....  then pauses the video.
how many pro bloggers can not or will not pause the video to get a complicated task done off camera that is too mundane for live video.
in spite of having all the tools at hand to do any reverse engineering task. even the most complicated if enough time is taken.
maybe Dave should do a video on time management skills when blogging , forward planning skills.
I had to learn the hard way when it came to posting home DIY video. 
as for Me posting video is 90% forward planning, 9% editing & 1% time uploading the video if its ok.
otherwise go back & repeat steps 1 2. till its ok 

[sean0118]

Also, really surprised there doesn't seem to be an input fuse, unless those input resistors are the fusible type?

I was under the impression that fusible resistors are flameproof...

Well they did fuse...   in a way 

[Johnny10]

Makes you think  about "right to repair"!   

[golden_labels]

holy moly even yt blogger Big Clive knows the value of reverse engineering a two layer pcb ,   

Dave and Big Clive have a different target audience. I would not expect Dave to dedicate his time to reverse engineering an already unusable trivial PSU on expense of other videos. Unless he finds a time generator machine or a human duplicator in the dumpster.

There is a solution, though. The next “alien” PSU, if it experiences an identical failure, may be sent to Big Clive. Everyone will be happy.