Casio GD-350: modifying your display to positive

Every day that passes, I like the Casio with vibration more and more. I find that it is a very useful system for alarms because there are some models that due to their 200 meters water resistance or their design, you can hardly hear them (maybe my hearing is not what it used to be).

Unfortunately, Casio models with vibration are not very common. One of the most complete is this GD-350, a GShock with vibration and a multitude of functions.

I had always liked the GD-350-8CR model, with its positive display, its strap and bezel in gray. But at the time of purchase it was not available on Amazon, and I purchased the GD-350 model with negative display, which was the model available at the time.

I have to admit that, aside from the new models with MIPS displays, the GD-350's negative display is one of the most visible in the entire Casio catalog. But still, in certain low light conditions, I found it very difficult to see the time.

So I took advantage of some free time and decided to positivize the display, since it looks much better in its positive version, as we can see in the following video:

We start

As we can see in the following image, this was originally the state of the GD-350 with its inverted display. This display is one of the best inverted displays I have seen, because of its contrast with the yellow digits, it looks really good.

Now, with Casio's new models with MIPS displays (such as the GBD-H1000 or GBD-100), inverted display watches are much improved, both in contrast and readability.

The first thing to do is to remove the module from the watch case.

We must remove the screws from the back cover to access the module.

Once the back cover is removed, we can access the inside of the watch. We can see the rubber sheet that protects the module on the back, and a bit of the built-in vibrator.

I take the opportunity to disassemble the bezel, so we can take the opportunity to completely clean the watch.

To operate the display, the module must be disassembled. The first thing to do is to remove the metal casing that joins it. An important detail is that we must not separate the vibrator from the circuit, since it is connected by a cable, and it could break. Moreover, it is not necessary, since the block containing the screen can be separated without any problem.

We remove the lcd from its plastic casing.

Removing the polarizing filter from the screen

For those of you who don't know, to switch from a negative to a positive screen or vice versa, we only have to turn the polarizing filter, as I explain in this guide.

As the filter is glued to the screen, we must first remove it. To do this, with a cutter or sharp knife, we separate a corner of the polarizing filter a little. To avoid damaging the lcd, once a corner is lifted, with a piece of polarizing filter I separate it little by little from the screen.

In this process we must be very careful and not be in a hurry. It is better to take more time and play it safe. Once the filter has been separated from the screen, we must clean the screen of any remaining glue residue.

The next step is to replace the polarizer.. To make sure that the position is correct, we must reassemble the screen together with the rest of the module without the polarizer.

Replace the battery and with the watch running, place the polarizer on the display and turn it until the display is positive and the digits are well defined.

We take advantage of the old polarizer to cut to the exact size of the new polarizer, keeping the position shown on the screen in positive (and that we calculated in the previous step).

Once the polarizer has been cut out, we place it on the screen to check that we have made the cutout correctly.

We remove the back plastic, glue it over the screen, and remove the top protective layer as well. We are almost done.

As I mentioned before, I had always liked the 8CR variant of the GD-350, especially the greenish stripe where the date and day of the week are shown.

Since I'm on the subject, I take the opportunity to test and do something similar. I cut out a rectangular piece and place it on the screen.

And it convinces me, it's not the greenish tone of the original, but I think that the screen with that slightly darker stripe can look very good.

I paste the second polarizer to make it definitive, as I like the way the screen looks with two tones.

We clean the screen from traces of dust, the inside of the case and mount the bezel of the case. We place the module inside the clock, making sure that the buttons work and make correct contact with the module.

Here we can see the huge CR2032 battery that allows you to have the vibration system and a duration of up to 5 years.

An essential step is to perform a reset of the module, joining the "AC" contact with the metal casing of the module with the tweezers.

We take the opportunity to lubricate the rear gasket with silicone grease. We place the rear rubber sheet that protects the module. And we check that the spring protrudes enough for the speaker to work properly.

Finally we screwed the back cover of the watch.

And this is the final result. As you can see, the readability of the screen has improved a lot and I really like the band in another color. Surely from now on I will use this watch much more.

Finally, we mount the strap and the "wings" on the bottom of the case and the watch is ready to use.

Things to improve

Once after mounting I have noticed things that have not been well:

• There are a couple of marks left below the hour digits. I don't know if I already had it in the polarizer or it was at the time of placing it, but I will surely change it again later, but for now it will stay there.
• To be more faithful to the 8CR model, the lower edge of the polarizer band could have passed a black permanent marker. In this way there would be a subtle lower black line, which I think would be better.
• Better cut the polarizer band of the date, if I look closely, I see that it is a millimeter shorter than necessary

Opinion about the watch

Although people with small wrists may find it uncomfortable because of its size, it is a model that fits perfectly to the wrist and with very interesting features that are not seen in other models. From access to the countdown with the push of a button, the display of the time in different modes, a very remarkable led, which almost dazzles in the dark. And its point, for me, more remarkable: a vibration system that will allow us not to lose any alarm to hear very low sound as happens in other models.

Really, I think that if you have no problem with its size is a highly recommended model for day to day.

Sale

Reloj Casio para Hombre GD-350-1BER

• Incluye cronómetro, temporizador y calendario automático
• Indicación de hora en el formato de 12 o 24 horas
• Cristal mineral, caja y correa de resina
• Resistente al agua hasta 20 bar / 200 metros
• La duración de la batería es de 5 años

100,77 EUR

Buy on Amazon

Advantages

• Vibration
• Relatively large digits
• Displays current time in all modes
• Quite powerful led light
• Special button for quick and direct activation of the countdown from clock mode
• High-capacity battery for up to 5 years of battery life.
• The "wings" system under the strap makes it fit very well on the wrist.

Inconveniences

• Large size, may not fit well for people with small wrists.

If you're as passionate about watch repair as I am, be sure to check out more in the Mods category, where you'll find in-depth articles similar to Casio GD-350: modifying your display to positive. Keep honing your craft with us!