Years ago I took my Protrek PRT70 for a new battery at a local mall battery replacement kiosk. Later when I collected it, the person manning the kiosk said the watch showed a ‘open’ message on the dislay and that I would need to read the manual and reset it.

The reset process in the manual didn’t make the ‘open’ message go away.

I used the watch for months afterwards, the analogue section keeping good time, but the digital section useless and annoying not be be functional.

After a lot of searching online for the symptoms I found a couple of forum posts with the same symptoms on other Casio watches – a tiny contact spring had obviously fallen out while the battery was being replaced at the kiosk – probably not noticed by the tech.

I searched a long time to see if I could find a source for the tiny spring without success – I cut a single strand of a wire that I could use as a substitute – I had to experiment with the multiple potential holes in the watch module until I identified the proper hole.

The wire hack solved the open message and I could resume using the watch again.

I still was looking out for a proper spring replacement as the bodge job was still a pretty ugly hack.

A few years later I found another forum post where some of the users had taken apart a watch spring bar – the spring inside was just about the right size and worked well as a substitute.

Following the notes on the forum post I got the thinnest spring bar I could find on AliExpress (1.3mm x 14mm). Ordered and delivered a couple of days later – probably one of the quicked AliExpress deliveries I’ve ever had!

Again the forum post notes helped – a pair of pliers at each end of the spring bar pulled it apart easily and gave up the tiny spring inside.

Even this tiny spring was too large for the spring hole in the watch module – I was able to gently screw it into the hole until it bottomed out. I gave it a quick test with the back of the watch hand held and verified the ‘open’ message was not there. I trimmed off the excess height of the spring with a pair of craft scissors and replaced the back with the screws in this time.

Awesome to have my ~25 year old faithful watch properly fixed