Casio GD-350 (GD-350-1BER) negative to positive LCD mod
Polarising film (the one used in this mod is for a Samsung phone, I just search on eBay for polarising film and set the price limit to £2. My tip is look for older models or similar, like iPods, etc, then check the sizing dimensions in a search engine, this way you can get more polariser for your money. :))
Some sort of thinner or similar for removing glue from LCD (I used Evostik 191 adhesive remover, this worked the best to remove the glue from the lcd front once the polarising film had been removed)
Silicone grease (for regreasing the gasket once the mod is done, keeping the watch watertight, I use Proopís but thereís a variety available.)
Iíve been wanting to do this since Iíve had my first GD-350, I think itís a pretty awesome watch with an awesome set of features (repeating cdt would be nice though, Casio!).
BUT!!! I wanted to have a reverse one. Not the grey background/black digits of the other models available (mind you, theyíre pretty scarce in the UK anyways and therefore pricier, pppffff), a reverse of the greenish-yellow of the digits.
So I scored one cheap off eBay and set to it.
Iíve written this tutorial out from the approach that anyone could do this modification should they want to, without any prior experience.
Iím confident enough to take digital watches apart now and dig into them, after poring over this forum for pointers and a couple of previous projects, one on this particular model (colouring the too-bright led to green).
Itís not particularly difficult just take your time really.
Note before beginning the modification:
There are 2 soldered wires on the pcb in this module, I havenít seen this on anything else Iíve cracked open yet. Iím pretty sure it is for the vibration motor as I canít think of anything else that is different on other modules.
Not really that much a pita if they snap but someone without a soldering iron or unfamiliar with soldering would benefit from not having to solder lolz.
Use a crosshead screwdriver (or flathead) to remove the backplate of the watch. once off be mindful of the small spring located top right.
Take out the gasket and spring and put them a sealy/ziplok bag for safe keeping.
If the spring doesnít remove at this point although it should (even though thereís a small tab sticking out on one side, I found on this model it comes out easily as thereís a tab in the hole it sits in) just be careful you donít lose it, itís needed for the alarm to sound.
Remove plastic separator. Thereís a small metal tab in the bottom left holding it down so watch for that, itís bendable so you can move it slightly as it helps ease out the module but not wholly necessary to bend it about a lot.
Ease out module, shouldnít need a lot of force although itís snugly seated in there, and away we go.
Taking the module apart:
I used a screwdriver with a flathead 1mm to pop the tabs of the casing open. quicker and easier than picking at them with a fingernail. :) I also left the battery in so I could test results on the fly.
Once all tabs open, carefully take out the separate parts. Watch for the conductive strips at the top and bottom of the casing as well as the pcb/wires as mentioned earlier.
Here they are all laid out:
pic of parts laid out
Removing the polarising film from the front of the LCD:
I used a standard double sided razor blade with one side taped off for removing the polarising film from the front of the LCD . Theyíre more flexible than single-sided blades thus making removing the polariser a little easier and lessening the likelihood of cracking or scratching something. Plus I didnít have any of the other and decided I was doing the modification then and there. :)
To begin, move razor blade slowly around edge of film then work way in. Eventually you should have a freshly unpolarised lcd!
But what is this?? 2 layers of polarising film on the front? (Iím not fully sure what this second layer of film is but it was unexpected).
1st layer off:
With a new piece of film, the digits go black, background goes to a grey/mid mirror type colour (like a standard/usual kind of lcd).
You can see in the top left corner of the LCD panel where some of this film has chipped off. This is more like I was expecting!
Both layers off (newly cut polarising film on far left):
The decal/markings of the bullseye target and lines across the main part of the screen are on underside of lcd. Wasnít expecting this and thought theyíd be going bye-bye once I cleaned the front of the LCD but itís a bonus for sure.
Use Evostik 191 for removing the glue on lcd screen, I initially tried rubbing alcohol but this worked a lot better. Drop a bit on and leave for a couple of minutes then rub off with soft rag or cotton pad (soaked in the evostik/thinner) in circular motions.
Before cutting to size, test the new polarised film against LCD to see reverse effect (In this case it would be making the LCD positive screen from negative)
Cut a new piece of film to the shape of the LCD. I used the original film I removed as a guide.
Sticky side up:
Sticky side down:
The green/yellow of original digits now show as background colour, digits a silver/grey tone. This was unexpected but I really liked the look of it so decided to keep as is. Note that bullseye target etc a deep red colour now.
Remove plastic covering sticky side of polarising film and place onto LCD carefully.
Now to the LEDs:
For colouring the LEDs, I used a Sharpie in Orange. I thought about using a gel filter cut to the shape of the lcd would possibly work as well but Iíve coloured in the LEDs on a mod to another GD-350 and it works really well, havenít had any lightening of the colour yet so no point making a task more difficult than it needs to be lolz. Colour in the LED on all sides and leave to dry, about a couple of minutes should do the trick.
Once done, piece it all back together and place back in watch. I chose to put the spring in last before replacing the caseback as I found it just falls out when trying to place it in the module beforehand.
Ooohhh!!!! Digits have a grey-blue tone, background thick and caramel/golden. Again, the digits going light blue was unexpected but a really nice effect. Iím guessing theyíre somewhat affected by the colour of the back of the LCD panel.
In normal daylight, the LCD is about as legible as the negative one, unfortunately itís a bit more difficult to read in low light and awful in really low light, something that I found wasnít a problem with the original black LCD.
It lights up fine in the dark and the results were as I expected. Hereís a shot with it next to the GD-350 with a green LED mod mentioned previously. :)
Total time taken: 1hr 30
Not good enough though.
This effect could possibly be down to the angle the original replacement film was cut but probably more my doing, who knows.
Not best pleased with it, too lazy to crack it open again and try something else tonight so MaŮana!
I totally changed my mind late on last night, low light legibility just not good enough. Back to the lab.:)
Notes so far: With the sticky side down on the new polarising film: I can get pretty much the original black and yellow, what I had on last night with the crappy view ability in low light.
Sticky side up:
I decided to take a few shots of the varying colours one could achieve from the polarising film at angles other than 90 and 180. Sorry about the blurriness of a couple but I wanted to share these to show the variety one can achieve as well as the sharpness/legibility of the lcd with such a modification.
pics for different colours at diff angles.
I ummed and aahed about a few of them but really wanted that blueish tone of the original modification alongside that golden tone of the background without the aforementioned extra crappiness.
I went with film cut at about a 15-30 degree angle of the original piece (cut in line with shape of the film piece I bought) and slightly larger than the LCD front, so that it would sit in the casing as there would be no glue to hold it in place.
Notice now the bullseye target and line are a pale blue, I can live with that, and totally in line with the overall aesthetic Iím going for here.
I left the plastic covering on the replacement film piece as it would be facing up out of the finished module and I didnít want to have stickiness just sitting there inside the module. As watertight as G-Shocks are I had visions of it collecting stray pieces of dust. At this point I couldíve just dipped it in thinners and rubbed the glue off but Iím impatient and wanted to see it done and (un)dusted.:)
Put it all back together, newly rearraranged to a suitable pleasing colour scheme,
The legibility is miles better now, at all angles, and more in line with what I was expecting when I tried this modification yesterday.
At this point I intended to go back in and remove the protective film from the front of the polariser, wipe the glue off with thinners and call it a job done, but I canít be bothered lolz it looks alright as is albeit for a small bubble, noticeable near the Ďdayí part at certain angles but not that noticeable in real life. Iím probably go find some more polarising film with no glue on either side but for now its workable and Iím pleased with the results (keeping the amberish background as well as the blue/clay coloured digits).
The lcd still has the same slight ghosting effect that is present on the original negative lcd.
The plastic still being on the sticky side of the film doesnít seem to affect visibility too much in regards to glare and reflection, it just looks ever so slightly hazy.
Iím not sure how clear or crisp the results would be if a modder choses to go with a different colour to what I went with in the end, but I thought Iíd throw those pictures up to show the possibilities.
Iíve uploaded all the pics I took while doing the modification to the site here rather than imgur or similar, as it was a kicker when reading up on articles here with all the notes but no images to show processes.
Best of luck and share pics or any findings if you choose to take this mod on!