Casio PRW-3000T: Glass cleaning

Casio PRW-3000T: Glass cleaning

In today's article we will look at a problem that is relatively common in Casio solar watches: the glass looks dirty. Unlike other models of watches that have a single crystal and are very easy to clean, in this model we find two crystals making a sandwich with the solar cell.

The problem with this design is that over time, it produces a "haze" that dulls the glass and is quite annoying. As can be seen in the following photograph, this is particularly noticeable in the area of the photoelectric cell. This haze effect is accentuated when looking at the watch from the side and in poor light.

Casio PRW-1300: neblina en el cristal
Casio PRW-3000: Fog on the glass

Here we can see more clearly what I mean. The glass looks dirty on the inside.

Casio PRW-1300: detalle del cristal
Casio PRW-3000: glass detail

The problem is that being a design formed by 2 crystals and the photoelectric cell in the middle, we cannot clean the faces of the crystals that are in contact with the cell, so we will not be able to remove the mist.

One option would be to remove the whole assembly with a press, but honestly, I have never been able to do so. As much as I've tried and been careful, it ends up breaking some of the crystals, so this was an opportunity to try a less risky alternative method.

Alternative cleaning method

A few days ago I came across a post on where a user explained the same problem. And it was also a Casio model with double crystal. What caught my attention is that he didn't try to remove the crystal and the photosensitive cell. What he did was simply to remove the module from the case, and clean the case with soap and water.

Then, with a hairdryer blowing hot air towards the watch display, he waited for all the water that had penetrated between the two crystals to dry. And the result was quite good, the truth is that I hadn't thought of that.

By not having to dismantle any of the glass, there is no risk of breaking any of them in the process.

Disassembling the watch

After thinking about it, I decided to try something similar. This Casio PRW3000 had that problem, and the truth is that for me it was quite annoying. In case the water could somehow damage the solar cell, I thought of doing something similar, but with isopropyl alcohol.

The advantages of isopropyl alcohol are that it is used for cleaning electronic circuits, so it should not damage the solar cell. In addition, it evaporates quickly, which makes it easier for us to dry the box completely.

The first step is to remove the titanium bangle, removing the screws that fix it to the case. Then we remove the 4 screws from the case back and the gasket.

Once we have access to the inside of the watch, we can see the rubber back sheet that protects the module from knocks against the back cover. An important detail is that this sheet is held in place by 5 small metal tabs, which we will have to bend to be able to remove the protection without any problems.

Casio PRW-1300: interior del reloj
Casio PRW-3000: Inside of the watch

Disconnecting the sensor

Once removed we can see the whole module. It should be noted that we have a flex cable that connects the sensor to the module. Before removing the module from the box, we must disconnect it. Simply use a pair of plastic tweezers to move it to the right so that it comes completely out of its connector.

Casio PRW-1300: modulo a la vista
Casio PRW-3000: module in sight

Removing the module from the box

Once the sensor has been disconnected, the module can be removed from the box.

Casio PRW-1300: caja vacía y sensor abc
Casio PRW-3000: empty case and abc sensor

Here we can see the module outside the case with the "open" notice to indicate that the watch has been opened. As can be seen, the digits are much clearer and more defined than inside the case.

Casio PRW-1300: modulo con pantalla limpia
Casio PRW-3000: clean display module

Dismantling the sensor

The next step is to remove the sensor. This is a delicate operation, because if it is not done carefully, we will lose the barometer, altimeter and compass functions, which are the fundamental part of this family of watches (Protrek).

The barometer compartment is formed by an external black protector, which is attached to the watch case by two screws. We remove them to continue disassembling the sensor.

Casio PRW-1300: detalle sensor barométrico
Casio PRW-3000: barometric sensor detail

Next is a metal plate with a small grid that allows the sensor head to be in contact with the outside.

Casio PRW-1300: suciedad en la protección del sensor
Casio PRW-3000: Dirt on the sensor guard

After this metal plate there is another one underneath, which we will also remove. Finally we remove the sensor. An important detail is that the sensor has to be removed from the outside of the case, i.e. we push the flex connector outwards so that the sensor head can come out.

A very important detail: we handle the sensor in such a way that it does not get caught by the sensor head, as we could damage it. We will also not clean it in any way.

Casio PRW-1300: Detalle de las partes del sensor
Casio PRW-3000: Detail of sensor parts

Clearing the fog

And finally, with everything disassembled (except the buttons), we proceed to pour 100% isopropyl alcohol inside the watch case. We wait a while for it to penetrate between the two crystals to eliminate the haze.

Casio PRW-1300: caja con alcohol isopropílico en el interior
Casio PRW-3000: box with isopropyl alcohol in it

After a while we can see how it has penetrated the inside of the glass. The streak on the left side of the glass is an air bubble, which is a good sign.

Casio PRW-1300: isopropílico entre los dos cristales del reloj
Casio PRW-3000: Detail of sensor parts

After turning the watch case for a while so that the isopropyl alcohol reaches all the corners of the glass, we turn the case, and insert a wire through the small holes (other than the screw thread) on the back of the case.

Evaporating alcohol

This way we push the bezel from the bottom and we will be able to remove it without problems. I do this because to dry the alcohol inside the box, I will place it on top of the router which provides heat. By removing the bezel, the glass is in full contact with the surface of the router and thus transmits the heat better.


Casio PRW-1300: bisel retirado para poder secar el alcohol
Casio PRW-3000: bezel removed to allow drying of alcohol

Reassembling the sensor

After a couple of hours of drying, I check the case and make sure that there is no trace of alcohol on the inside or between the crystals. If so, we can start reassembling the watch.

Casio PRW-1300: caja con el alcohol ya evaporado
Casio PRW-3000: box with the alcohol already evaporated

To mount the module, the first thing I do is to open the metal tabs as much as possible so that they don't get in the way when inserting the module into the box. I introduce the module inclined, with the right side lower and trying to place the flex of the sensor in its connector. Once it has been inserted, I proceed to adjust the module in its final position.

Once the module has been inserted into the box, we must finish connecting the sensor definitively. Using a pair of plastic tweezers, we push the sides of the sensor little by little until it is finally inserted into its connector.

Casio PRW-1300: montaje del modulo y conexión del sensor
Casio PRW-3000: module assembly and sensor connection

Assembly of the protection

Once the sensor is connected, place the rubber sheet on the module, adjust the 5 metal tabs to hold the sheet against the back of the module.

Casio PRW-1300: colocación de la lamina trasera de protección
Casio PRW-3000: fitting the protective back plate

We took the opportunity to lubricate the rear seal with silicone grease, and we placed the back cover temporarily to check the operation of all the buttons, barometer and alarm sounds.

Casio PRW-1300: colocación de la junta trasera
Casio PRW-3000: fitting the rear seal

Once checked, we screw the screws in a cross shape without giving the final tightening. Once the 4 screws are in place, we give the final tightening to the screws.

Final appearance

And that's what our brand new Protrek looks like, a huge difference.... 😀 😀

Casio PRW-1300: resultado final, pantalla completamente limpia
Casio PRW-3000: final result, completely clean display

Casio PRW-3000 Mini Review

The PRW-3000, as a member of the Protrek family, is designed to be extremely rugged and useful for outdoor activities. One of its main features is that its size is smaller, lighter and thinner than previous models, offering a refined and modern design.

Its water resistance is 100 metres, and it includes, thanks to its triple sensor, survival features such as temperature, barometric pressure (including a storm alarm), as well as an altimeter.

Thanks to its solar cell, we will forget to change the battery for many years. It has a white light that backlights the display, with the possibility to switch on automatically when the ambient light level is very low.

In world time mode it has 31 different time zones. It also has five alarms, four of which are normal alarms and one with snooze, as well as a time signal. It should be noted that the sound of the alarms is powerful, without problems to hear it as happens with some gshock models.

There is also a countdown timer and a stopwatch accurate to 1/10th of a second. The calendar is perpetual until the year 2099.

The Casio PRW-3000 is extremely comfortable to wear on the wrist. If you are looking for a useful, durable and modern watch, the Casio PRW-3000 is an excellent choice.

Casio Pro Trek PRW-3000-2ER, Es-0309-ko632, Pulsera, Es-0309-ko632, Pulsera
  • Funciones: altímetro, barómetro, brújula, calendario, cuenta de revisión, radiocontrolada, termómetro
  • Marca: Casio
  • Embalaje: caja original Casio
  • Garantía del producto: Garantía internacional Casio
  • Género: Unisex

The Casio PRG-300 is the equivalent model, but without the radio-controlled time setting system:

  1. Alternative cleaning method
  2. Disassembling the watch
  3. Disconnecting the sensor
  4. Removing the module from the box
  5. Dismantling the sensor
  6. Clearing the fog
  7. Evaporating alcohol
  8. Reassembling the sensor
  9. Assembly of the protection
  10. Final appearance
  11. Casio PRW-3000 Mini Review

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