Failed Philips 46PFL8008S/12 display repair (#P15)

And now for the thing that didn’t make it #100 ;)

A while back, I was donated my second “defective” TV, a 46″ Philips 46PFL8008S/12 with the large ambilight (left/2x top/right with 9 LEDs each). Unlike my first donor which pretty much suffered a direct lightning strike (as described in rant #R2), this one turned on just fine. What’s wrong with it, why would you give away a former 1500€+ device?

(bonus brownie points if you can name the show currently displayed here!)

Well, story is this poor fella cracked a glass table. Thing with glass tables is that shattered glass is a royal pain in the butt to deal with. And on the way down, this TV had its fair share. Polarizer film scratched, and so are the metal front (no plastic bezel for design reasons) and to a lesser degree the mount. Works, but the permanent white spots certainly annoy the heck out of the viewer.

So it was donated, and given the early 2000s fad of removing the polarizer of brand new LCDs to put them on your glasses (yeah :roll: works, but is impractical! ), I was curious if that film can be replaced. Spoiler: Yes, but probably not at home…

First thing to do is finding a suitable replacement polarizer. Which is pretty easy as the only one sold in 46″ size on AliExpress is the 0° orientation type, but I didn’t feel like shelling out 30 bucks unless I knew this would fit. If this was 45° TV for example I would be out of luck in terms of spare parts. So I ordered the cheapest 0° film available from that seller, which was a 32″ one for 9.98 USD including shipping. Some sellers on AE also offer reference glass sheets which are just wee glass plates with such film and 0°/45°/90° markings – for basically the very same money. I went with the entire 700x400mm² sheet that came rolled up in some PVC drain pipe – for that the 10 dollars are actually a pretty good deal.

What can I say, once you have a reference, it’s pretty easy to tell the polarizer orientation of your existing device.

0° looks fine, 90° yields a black image except on the parts that are damaged. +45° and -45° don’t do much, and to my knowledge there are no wonky orientations like 22.5° in use. The 0° image also shows why just adding a patch wouldn’t work – you can clearly see edges and imperfections, so an entire swap is necessary. I decided the 0° 46″ film will do – ordered for 29.88 USD/27.02 EUR including shipping.

While this is above the 5.00€ “must pay” VAT limit of German customs (19% tax sums from 4.18€ to 5.00€ for goods values of 22.00€ to 26.32€ can be enforced, stuff below 22€ is VAT free), they didn’t respond to my “I want to pay my taxes on mislabelled items, please send me a bill like last time” request. Well, thanks, I guess? Worked fine last time for the much more expensive LEDs in the#P8 growlight repair post.

Anyway, for those that prefer not to order a throwaway item and wait an additional month, here’s the thing: If you do have a linearly (!) polarized film of unknown orientation at hand, just go outside and determine it yourself. 0° Chinese orientation is equal to “sky reflections on glass vanish”, e.g. on car windows or your neighbour’s roof lights, while they max out in ±90° orientation (180° mismatch cancels out, as these are just very long molecules in perfect parallel alignment). You can check for linear polarization of your material if you have two pieces on top of each other – their order shouldn’t matter and there’s no funky business when you turn one upside down. If they do (3D glasses!), they have circular polarization. It’s a bit more tricky with those.

Of course one could just determine orientation by Brewster’s angle experiment (light polarization under a certain angle) in the lab, but that’s the physicist talking. Go watch your neighbours :lol:

0° and 90° orientation of my test piece – notice how the glass clears up and also the paint gets dull due to lack of reflected light. Rear windows show nice patterns due to the tempered glass that breaks in thousands of small and dull shards, which occupants often prefer to long and deadly ones flying around in a crash.

For those that do not have any polarizing films at hands, I still can give away plenty of my 32″ sheet material. Drop me a note below.

Now, back to the TV itself. For a new film, as shown, the old one has to come off. Which is relatively easy for new screens, but mine has been on for quite some time. Can’t tell exact figures, but the operating hours timer in the service menu says 32k hours (3.7 years) – this modern standby crap doesn’t really help all that much. Thing is: The polarizer film is brittle, but the glue is still perfectly fine. You can see the properties of new film above where a slice came off during normal handling, now imagine that on 100×60 cm². Youtube tricks like adding window cleaner do not help much, this film was too old. It works on newly applied films, though.

For all masochists out there that want to try: Don’t expect to clear more than 1500cm² (~ one 22″ display) per hour as a beginner. This is my progress over 55 minutes:

This was captured with my RX100M2 and the Timelapse for Sony cameras Android app from Thibaud Michel (Michel Thibaud?). While it is buggy (see me fiddling around with the phone), it does work once WiFi is stable and the phone is on the charger.

After that, I pulled the images from the camera using airnef (I think I already praised this?) and used the very simple instruction from elbebilder.de:

Rename to successive numbers:
#!/bin/bash
a=1
for i in `ls -rt *.JPG`; do
new=$(printf "%04d.jpg" ${a})
cp ${i} ./renamed/${new}
let a=a+1
done

Resize for smaller video size and render effort:
for i in `ls *.jpg`; do convert ${i} -resize "1604x1080^" -gravity center +repage fullhd_${i}; done
(modified from original instructions as I do not want a center crop; also I need a different resolution due the 3:2 image format of the camera)

And combine it to an MPEG file for further processing on Youtube – this file is only 6.2MB for 306 frames of (close to) FHD video, I would have expected several hundred megabytes, especially after the few seconds of processing time on my old C2D machine!
ffmpeg -f image2 -i fullhd_%04d.jpg -r 25 -vb 4096k timelapse.mpg

Check if something got damaged, go on, repeat…

Last picture is taken once again with a polarizer in front of the camera. You can see the glue residue and the zones that are clean, which happens when you can grab and pull up a piece instead of cutting the glue with a blade. Which…can get messy:

On the other hand, you don’t want to put excessive force on the glass pane, I had one 15″ test LCD crack in preparation of doing this. And frankly, this isn’t tempered glass, this stuff breaks into REALLY nasty shards with sub-mm thickness. I’m really lucky that accident didn’t create a literal puddle of blood from stuff flying around and sticking into every exposed piece of skin, plus the residue that is conveniently picked up with socks…

Hours later, the entire surface was removed. Cleaned several times, changing blades is a pretty good idea to help with that. Final check:

:suspect:

Well, that is crap inside of the glass panel. Factory imperfections!

A colleague supplied me with film samples for window tinting, I wanted to exercise film application before using the real polarizer. At that stage I knew I was into trouble, as bubble-free application was MUCH easier than dirt-free application…

I can however recommend the Avery Pro XL squeegee, very comfortable, durable, yet a little expensive for what it is. Might be a little too big for e.g. car wrapping (notice the “XL” part…), but for surfaces with little to no curvature, this is a great tool.

Once you mess up the film application once, you’re done. And contrary to my expectations, angle alignment wasn’t one of the difficult parts. It’s dust. Even if you can get rid of stuff that is on the glass, the crap on the glue of the film never goes away without permanent visible damage to the glue. Sorry for the anticlimactic lack of photos here, but apart from funny rainbow specks of dusts, there’s not much to see:

(the wavy patterns are residual amounts of water below the film, which is a useful thing to have. Careful however what else can get in contact with the glue, e.g. window cleaner and isopropyl alcohol do make it slightly opaque after hour long exposure, while expectedly acetone does that straight away – including damage to the polarizer itself)

It works, but it looks like a rainbow turd.

As spoilered before: This is entirely feasible to do IN A CLEANROOM. Your living room won’t do it. And your bathroom (after a shower, as often suggested, to get dust levels down) probably won’t cut the mustard either. You pretty much have to work upside down for that large display surface and then there’s still the problem of removing the protective film from the polarizer glue side, which in hindsight might have caused the majority of particles present on my first try. So, to sum that up: Don’t do it. Not worth your time, not worth your money. Interesting to do, nonetheless, but entirely in vain. Do what I did next: Buy another unit with a different type of damage and swap parts.

Which I did with ease, as these PFL8008S series (40″, 46″ and 55″ models) pretty much die because of the very same thing over and over: A dead main processor, probably a combination of crappy lead-free solder and insufficient heat sinking. I was able to pick up one for 66€ like 200km away, which wasn’t all that far to drive because I had a stop right in the middle for a sick visit of a family member. And having a working unit plus parts of another faulty one means that checking and selling spare parts was a breeze – I haven’t calculated the exact amount, but I have easily made the 66€ for the defective one back, plus probably the fuel for the trip. Plus I was able to help quite a few people with these parts, as ordering an entire 40-55″ screen for salvaging a wee flat flex cable is still off-putting to most tech savvy people that come that far in the troubleshooting process. Win-win!

One more thing: I also did remove the ambilight modules from the back panel which might not be a great idea, but again it’s more handy than posting a square meter of plastic for a defective LED. While I had these out, I wondered if they could be used in addition to the four built-in ones…and they do work.

As far as I have tested these, they aren’t programmed to any particular orientation on the display, but they work similar to WS2812 or SK6812 modules. Decoding data that is meant for them and passing on a modified version of their input. So they might just decrease some orientation bit/byte, which is why the 5th module has identical colors to the 1st, the 6th equals the 2nd and so on. So replacement should be pretty easy. Removal is also easy, use a hot air gun and a spatula, the glue however will have to be replaced. Do not bent, as these thin PCBs will stay that way. The main thing however, adding more ambilight zones, probably won’t happen without a large firmware modification. Bummer.

The service menu can be opened by starting the TV, dialling (front of the remote!) 062596 and the Info key. It’ll tell you to shut off your TV now as further progress will void your warranty…but: These high-end TVs have a lousy 2 year warranty period (Philips knows why, and also why they do not sell functional mainboard spares!), and mine not only had >3y of uptime but also a full LCD swap – so f*ck you Philips, of course I’m gonna access the service menu. Full backup including alignment information is attached:

USB settings export

Any information regarding matrix alignment is appreciated, I’d like to know how modules and zones work. And I’m curious why my left panel was set to 233 brightness while others (why 00 to 99?) are set to 255. And so on, and so forth… ;)


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