Casio BM-200 – Restoration

Introduction

I bought a Casio BM-200 on eBay because I like strange and forgotten Casio ideas from the early 90s. The auction photos were not very clear, but the shape of the BM-200 always caught my eye. It has a bold rounded case that looks nothing like the older BM-100. Many collectors call it the “Jason Mask” because of the front sensor grill. It feels like a mix of sci-fi and old VHS horror vibes.

I wanted this watch for two simple reasons. First, the BM-200 is an important moment in Casio history. Around 1991, Casio tried to push barometer watches before the ProTrek era. Second, I enjoy restoring “dead” watches. There is something fun about opening an old resin model and trying to bring it back to life.

When the BM-200 arrived, I did the teardown right away. I expected a standard rescue job. Instead, I found a much bigger challenge. At that moment I knew this restoration would take more work, more cleaning, and probably a few surprises. But that is part of the hobby and part of the fun 😅.

In the end, the project turned into a mix of repairs, testing, and smart part swapping. The final result was worth the effort. The watch works, looks good, and still has that unique early-90s character that makes the BM-200 special.

What was the condition of the watch at the start?

When I opened the Casio BM-200, I quickly understood why it needed serious work. The outside looked normal for an old resin watch, but the inside told a different story. After removing the caseback, the first thing I saw was a dark metal plate that connects the module. It had a burnt look with black spots. This often means the watch had a short circuit at some point. The batteries were old and empty.

Next I opened the module. The PCB was in very bad condition. It had corrosion and blue stains from leaked battery acid. Some traces were broken. A few contacts looked weak or damaged. With a board like this, the module usually needs heavy repair or a donor.

I cleaned the board with alcohol and a soft brush. I repaired a few traces using conductive paste applied with a thin needle. After that I tested the module with fresh batteries. The backlight turned on and did not turn off, even after AC reset. This is a classic sign of PCB damage. The module did not start. At this point it was clear that the original PCB was too far gone.

The sensor was also in rough shape. The contact pads were dirty. The small springs that connect the sensor to the PCB looked tired. The sensor surface had heavy wear. Finding a fully working BM-200 sensor today is rare, so I knew I needed a second watch for parts.

The good news was that the original case was still solid. So the project was still possible. I just needed a working module to continue the restoration.

Restoration Process — Step by Step

1. Cleaning the Original Case

I started with the original BM-200 case because it was still in good shape. I washed it with warm water, a soft toothbrush, and mild soap. This removed old dust and skin oils. After that I cleaned the smaller areas with cotton swabs.
The resin of the BM-200 is soft, so gentle cleaning works best.

2. Inspecting and Testing the Damaged Module

Next I focused on the original module. I checked every part under good light. I cleaned corrosion with alcohol. I brushed off battery acid using a soft brush. I repaired a few PCB traces with conductive paste and a fine needle.
After testing with fresh batteries, the backlight stayed on and the module did not start. The damage was too deep, so I stopped wasting time on it. I decided to look for a donor.

3. Finding a Donor Watch

I searched for a second BM-200 with a working module. I found one with a destroyed case but a good inside. This is the best situation for a restoration. Good module. Bad case. Perfect donor.

4. Cleaning the Donor Module

When the donor arrived, I opened it and removed the module. I cleaned the contacts and checked the springs. Everything looked healthy. The board had no corrosion. The module reacted well during a quick test.
This was the new heart of my project.

5. Transplanting the Module into the Original Case

I placed the donor module into my original case. The fit was perfect because both watches shared the same layout. I checked the rubber gasket and applied a small amount of silicone grease to keep it soft and watertight.

6. Restoring the Crystal

The crystal had many scratches. I sanded it slowly with fine grits (starting around 1000 and moving up). After removing the deeper marks, I polished it with Polywatch. The crystal became clear again and the front of the watch looked much better.

7. Refinishing the Lettering

The BM-200 has engraved text around the bezel. The letters had lost color over the years. I filled the engravings with acrylic paint using a small brush. After the paint dried, I wiped the extra paint with a damp cloth.
The text became sharp again and the watch regained its “casio look”.

8. Rebuilding the Sensor Setup

I moved the better donor sensor into the case. I cleaned the contact pads. I checked the small springs that press the sensor against the PCB. Everything looked fine. But after testing I still got ERROR on the screen.
This sensor system is very sensitive. Even small problems can break the measurement. I decided to leave the sensor for a future project.

9. Installing a New Strap

I ordered a new original strap made for the BM-200. The shape is very specific, so using a correct strap helps the watch look complete again. The new strap changed the whole look and made the restoration feel finished.

10. Final Assembly

After cleaning, polishing, swapping parts, and testing, I closed the case, tightened the screws, and did a final wipe. The watch looked clean, fresh, and ready for a new life.

Result

After everything was cleaned, swapped, polished, and assembled, the Casio BM-200 finally looked like the watch I always wanted to restore. The shape, the rounded case, and the “Jason Mask” sensor grill all came back to life once the scratches were gone and the lettering was fresh again. The new original strap completed the look and made the watch feel like a proper early-90s outdoor Casio again.

The donor module worked perfectly. Timekeeping was stable. Button response was good. The backlight worked as it should. For a watch that started as a “for parts” gamble, this already felt like a big win 👍.

The only thing that still fights me is the sensor. Even with the better donor sensor and clean contact pads, the watch still shows ERROR. These early barometer systems are sensitive. They do not like corrosion, weak springs, or tiny breaks in the PCB. I will return to it in the future, because fixing the sensor would complete the project. But for now the watch is fully wearable and looks great on the wrist.

Want your Casio restored?

If you have a vintage Casio that needs cleaning, polishing, module work, or a full rebuild, I can restore one for you. I work with old resin models, barometer watches, G-Shocks, and many classic modules.

If your watch has faded letters, scratched crystal, dead buttons, weak contacts, or needs a donor swap, I can take a look and bring it back to life.

Send me a message with your model and the problem. I’m happy to help another collector keep these old Casios running. 👍⌚