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Old 03-22-2018, 06:35 PM   #11 (permalink)
In the fasting lane
 
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Microwave fixed LED - and lots of wasted ones

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

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2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.17 Gmeter or 0.1 Mmile.



Investors woes:
"In hindsight, I should have placed a bet on the horse that won the race"
"In hindsight, I should have bet more on that horse"

Last edited by RedDevil; 03-22-2018 at 06:56 PM..
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Old 03-22-2018, 07:52 PM   #12 (permalink)
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That is ghostly!
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See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.



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Old 03-23-2018, 04:18 AM   #13 (permalink)
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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).
__________________
2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.17 Gmeter or 0.1 Mmile.



Investors woes:
"In hindsight, I should have placed a bet on the horse that won the race"
"In hindsight, I should have bet more on that horse"

Last edited by RedDevil; 03-23-2018 at 07:13 AM..
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Old 04-10-2018, 09:14 PM   #14 (permalink)
Cyborg ECU
 
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Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 66.42 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
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Thanks: 2,373
Thanked 2,155 Times in 1,463 Posts
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.
__________________
See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.



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Old 04-11-2018, 03:01 AM   #15 (permalink)
In the fasting lane
 
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Location: Nieuwegein, the Netherlands
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Red Devil - '11 Honda Insight Elegance
Team Honda
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Thanks: 1,687
Thanked 2,203 Times in 1,427 Posts
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.

__________________
2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.17 Gmeter or 0.1 Mmile.



Investors woes:
"In hindsight, I should have placed a bet on the horse that won the race"
"In hindsight, I should have bet more on that horse"
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