59 lines
2.5 KiB
Markdown
59 lines
2.5 KiB
Markdown
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date = "2020-03-29"
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title = 'Repair: Philips 42" 3D LED TV with Ambilight - AGAIN'
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tags = ["repair", "audiorepair", "philips", "tv"]
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categories = [ "Audio Repair" ]
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summary = 'This week our Philips TV died. I repaired it before, and it seemed the problem was back.'
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About a year ago I [repaired a Philips 42" 3D LED TV](/projects/repair-philips-42pfl6057h-12/). I like
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this 1080p Ambilight TV quite a bit, so I installed it into the living room where it has been in
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service since February 2019.
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Last week, during a period of self-isolation due to the Cornoavirus wreaking havoc around the world, the
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TV died again. It has the same symptoms as before:
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* Would not turn on
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* No blinking red LED
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* Red LED would blink fast on remote control input
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The TV is used intensively. Although it's placed in a well ventilated spot, it would not surprise me
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if the Fusion IC had suffered some thermal damage to it's BGA soldering again.
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![Spilled TV Guts](spilled-guts.jpg)
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The back of the TV comes of easily enough and the heatsink, which as a bit loose, came of quickly as
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well.
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![Heat it up](heat-it-up.jpg)
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Having learned from my previous repair I used a bit of heat resistant Kapton tape to hold the small
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passives around the IC in place.
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Keep in mind that the top of the IC is _designed_ to get rid of heat and you want to heat up the solder
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balls underneath the IC. That means I've set the temperature of my hot air station quite high (400°C)
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whereas the melting temperature of lead free solder is 217°C.
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After a few minutes of heating up the IC I decided to let it cool back down and tried turning on the
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TV. It worked like a charm again.
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## Heatsink solution
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The Fusion IC is decked out with a ceramic heatsink on top and a block of heat transferring foam on
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the bottom between the PCB and the metal chassis.
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The ceramic heatsink is held in place by a small piece thermal adhesive tape. Well, it used to be. After
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my previous repair I placed it back. It didn't hold, so I used some cable ties to keep it in place. I
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should have know the effect of the thermal tape would be lost. This is like sticking a huge copper cooler
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on a CPU without thermal paste.
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Well, I'm all for not making the same mistake twice.
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I bought a piece of 25mm x 20m of thermal adhesive tape from Amazon.de. I removed all residue from the
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old tape and stuck it back on. This should improve thermal conductivity quite a bit.
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![Thermal Stuffs](thermal-stuffs.jpg)
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After that I put everything back together and we have a working TV again :-)
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![Featured](featured.jpg) |