Polarizer Replacement

Howdy from an occasional lurker.

I seem to recall some mention of the gameboy polarizer replacement video a while back. My 2kxl screen had some slight burn when I got it, but it seemed to have got a lot worse recently. The holidays mean I have a bit of time on my hands so I thought I'd look into fixing it (or replacing with an mpcstuff one).

Came across http://dothkoi.blogspot.com/2019/02/akai-mpc2000.html and decided I had nothing to lose by having a go. Long story short, I now have a lovely clear screen.

Time&materials: a couple of hours, a few ml of nail varnish remover (from the other half) and a 700 yen sheet of polarizer film. (Which was way too big - the original polarizer measures about 117mm x 31mm)

Process (for those of you who don't read Japanese )

Check the orientation of your new polarizer sheet before starting.

Take the LCD assembly out, and dismantle (as per mpcstuff screen replacement)

Remove black metal bezel (by bending the little tabs on the rear side away from the PCB) to get at the actual LCD

CAREFULLY unfold glass part from PCB

The top face of the LCD is the problem. Remove the old polarizer. I did it by lifting a corner with a cutter/razor blade and peeling off. It leaves a ton of old hardened adhesive on the glass.

Remove the old adhesive with acetone/nail varnish remover and use a cutter/razor blade to scrape it off the glass. Patience is the key. Avoid getting acetone anywhere execpt the LCD face, and be careful of stressing the flat cable and connectors!

Once it's nice and clean, Cut out a piece of polarizer and attach it to the screen however you like. I taped it to the inner face of the LCD window (ie. the inside of the main bezel, on the back of the 'Integrated Rhythm...' window)

Reassemble the unit, cross your fingers (to ward off LCD lines) and fire it up

Wish I'd taken a 'before' photo, but the screen pic at the above link was pretty similar. We all know what they look like, right?

After:



Searching didn't turn up any similar posts, so in the spirit of the season (and giving a bit back for all the info I've found on here) I thought I'd share it. If anyone knows a better method of removing the old adhesive (than my acetone and razors attempt), so much the better!

Good share. To make it easier to remove the polarizer you could use a hair dryer. Move it back and forth until it warms up the glue, then slowly peel. For the residue: WD 40 or Kure CRC 5-56. Apply, Let sit a few minutes then wipe.

is there nothing a little wd-40 cannot solve?

NearTao wrote:is there nothing a little wd-40 cannot solve?

Faders!

CharlesRandolph wrote:Good share. To make it easier to remove the polarizer you could use a hair dryer. Move it back and forth until it warms up the glue, then slowly peel. For the residue: WD 40 or Kure CRC 5-56.
Apply, Let sit a few minutes then wipe.

I am sure you have good intentions with your advice but you're unfortunately misinformed. While heat would make sense in situations with removing of glue, stickers, laminate, etc - it won't be safe to utilize in this situation.

Using any form of heat such as a hair dryer with LCD screens of this particular design will guarantee that the electrically bonded ribbon connector which maintains connection from the LCD encoder to the screen will be damaged.

Heat from the CCFL bulb which sits where the folded ribbon connector is the main fault and cause of lines and the eventual loss of use on the screen. So I'm sure you could imagine how using something that emits much higher heat wouldn't be advised.

The original posters way of doing it, while it'll take time to do is much safer. Now if only a more sensible low temperature replacement for the CCFL can be found.

richie wrote:

CharlesRandolph wrote:Good share. To make it easier to remove the polarizer you could use a hair dryer. Move it back and forth until it warms up the glue, then slowly peel. For the residue: WD 40 or Kure CRC 5-56.
Apply, Let sit a few minutes then wipe.

I am sure you have good intentions with your advice but you're unfortunately misinformed. While heat would make sense in situations with removing of glue, stickers, laminate, etc - it won't be safe to utilize in this situation.

Using any form of heat such as a hair dryer with LCD screens of this particular design will guarantee that the electrically bonded ribbon connector which maintains connection from the LCD encoder to the screen will be damaged.

Heat from the CCFL bulb which sits where the folded ribbon connector is the main fault and cause of lines and the eventual loss of use on the screen. So I'm sure you could imagine how using something that emits much higher heat wouldn't be advised.

The original posters way of doing it, while it'll take time to do is much safer. Now if only a more sensible low temperature replacement for the CCFL can be found.

I guess I got lucky, when I changed mine. So anyone who reads what I wrote, do it at your own risk. I wouldn't want it to destroy anyone's screen. Thanks for the heads up.

richie wrote:
Using any form of heat such as a hair dryer with LCD screens of this particular design will guarantee that the electrically bonded ribbon connector which maintains connection from the LCD encoder to the screen will be damaged.

CharlesRandolph wrote:I guess I got lucky, when I changed mine. So anyone who reads what I wrote, do it at your own risk. I wouldn't want it to destroy anyone's screen. Thanks for the heads up.

I did think about the hair dryer, but recalled some posts about a possible connection between heat and lines so played it safe. Didn't hit on WD40 though, so thanks. To my shame, I've just realized we don't have a can in the house

richie wrote:Now if only a more sensible low temperature replacement for the CCFL can be found.

I haven't looked at any schematics, but as I'm about to order some phone backlights to do this with my S3000XL, I wonder if one of those might be pressed into service somehow? I know nothing about these backlights beyond 'my phone doesn't appear to get hot' so there may be any number of reasons why it won't work...

leeb wrote:I wonder if one of those might be pressed into service somehow? I know nothing about these backlights beyond 'my phone doesn't appear to get hot' so there may be any number of reasons why it won't work...

Based on the link, it could be cut down to size but I'm not sure of the safety. The thing is that the 240x64 LCD screens from back when had a very narrow gap in it for slipping the EL sheet in and out.

As you've experienced with the 256x64 screen for the MPC 2000/XL, while I do believe could fit - my concern would be how the operating wavelength of that inverter could possibly interfere with the screen's encoder (as it would be pressed up right against it. And then secondly, I want to know about the heat profile the screen would have.

My idea would be using an implementation (finding a google image to cite isn't working out right now but basically you'd have a clear plastic tube that would replace the real estate that the CCFL would and then at the end of the tube you'd have 1 LED which would luminate that entire tube. With that, there'd be no risk of increased heat around the bent electro-welded ribbon connector. Let me know if you get what I'm saying or if I'll need to draw up a diagram.

I've searched for an led equivalent with the same footprint as the original CCFL to no avail:

This is how it would look like:



There was also a new design mod done, a full replacement board and shared on this forum to replace the CCFL backlight for the MPC 4000 but the persons name is escapes me a the moment.

leeb wrote:I did think about the hair dryer, but recalled some posts about a possible connection between heat and lines so played it safe. Didn't hit on WD40 though, so thanks. To my shame, I've just realized we don't have a can in the house

It was no lose situation when I did because I had a new screen already, just in case it didn't work. I don't hold the blow dryer over the screen like a blow torch. It was 12 inches away, low heat, constantly moving it back an forth, for about 30 sec to 1 minute. As I said, I had nothing to lose. I only used WD 40 because I didn't have IPA in the studio at the time.

But Richie knows what he's talking about, modding and repairing electronics is his field of expertise. I was just trying fix it and get back to making music.