Ghost fixes lightbulb

[RedDevil]

Yup, you read it right. I fixed a T10 LED by putting it in a microwave!
Repairing without touching, the microwave fills in the ghostery in this case.

When I got a new laptop at work the sysops told me there was this guy that bought laptops that had a screen failure or other problem but were physically intact. He'd disassemble the screen (or whatever the malfunctioning part was) and put it in a microwave for a few seconds; that often restored its functionality.

Well that sounded too good to be true.
But I had that collection of failed LEDs. What if...?

So I gave it a try.

Here's the before:
T10 crossboard lamp with 24 SMC LED's of which only 3 rows of 3 lit up.


Microwaved for about 2 seconds at about 900W, together with an identiical lamp that also failed partly. At 2 seconds it flashed and I killed the microwave within a quarter of a second.

After that, when tested one lamp lit up completely!


Success! It works. The world is my oyster!

The other lamp had not improved. Gave it another burst in the microwave.
Sadly, that killed it.
But at least, one of the lamps was definitely repaired.

Spurred on by this success, I tried it out on a collection of misbehaving or completely failed LEDs and killed all but 1 of those.
Two T10 LED towers with ever so tiny SMC's that had faded to a shimmer.
1 second in the microwave restored most of those SMC's to original brightness. But not all.
A second dose than. Spark. Black spots on the LEDs. A writeoff.

One H11 fog light that had only 4 of its 10 high power SMC's lit up - or none at all, depending on the tide. Lit up briefly in the microwave. Restored those 4 LED's to continuous working, but not the rest.
Another dose then. Total fail.

A collection of housing LED's (E14 and E27 plugs, 230 Volts). The microwave either did nothing to them or killed them.

Conclusion:
A short burst in the microwave could restore your dim or failed LED's, but it works just in a minority of cases. Too short and nothing happens. Too long (2 seconds typically does it) and it is dead.
See them light up, then you have a chance if you kill the microwave at that very moment. See a spark, then throw it away; no need to even test it anymore.

In hindsight I might have put some buffer in the microwave with the lamps, like a glass of water.
I did not so I can't tell what effect it would have. My collection of doubtful LEDs is depleted now, so I can't do an encore.

Whatever you do, ventilate well.
Do not increase the time beyond 2 seconds; that will only bake the LEDs (they get black spots).

But it was fun trying

[California98Civic]

That is ghostly!

[RedDevil]

It is actually pretty simple.
These LEDs and many other electronic components are made in the cheapest possible way; that is, good enough to pass quality control and initial testing.
Little consideration is given to the stresses the repeated heating up and cooling down cause over time.
Hairline cracks appear in the soldered connections and the component fails.

When you put 2 metal objects very close together in a microwave, you'll see a spark between them. The hairline cracks are bridged, re-solder themselves and the component works again.

The problem is that other gaps can be bridged too - if they are not supposed to they'll fail. The PN layer in diodes, transistors and ICs is vulnerable.
Also anything metal quickly heats up by itself - and LEDs are notoriously heat sensitive.

So there's a minefield of possible problems.
But if you have a failed component that you can't or won't repair otherwise, good ventilation and it's not your microwave anyway, why not give it a try?

You can better step it up very gradually indeed or use a buffer like a glass of salted water (to aid conductivity).

[California98Civic]

Horn died while I was wiring radiator fan on/off. Tested horn itself by connecting directly to battery: loud AF. Tested relay with known good swap: no change. Checked fuse: perfect looking (perfect!).

Drove to LA for work, and on the way home horn started working again.

Thank you, ghost.

[RedDevil]

Half of the LEDs in the microwaved lamp have since died again It ain't much of a fix.
Bet the thermal stresses have no difficulty in causing new breaches.