Seiko’s iconic A239 World Timer is a great example of how a dual-layer LCD can give a watch so much more functionality at the press of a button.
World Time watches, even Seiko’s own M158 (Pan Am) and A708, usually relied on having a small marker (like the size of the day indicator on many LCD watches) appear at various points around the display to indicate the time in a particular city/country/zone.
The A239 went one better by putting a world map on a separate LCD, split into sections which lined up with the country or time zone being indicated.
It offered the option for a daily alarm, as well as a separate world time alarm. While it was copied/pirated and became the World Time Melody Alarm watch for low-cost distributors Armitron, Caravelle, Zeon and others it’s popularity never waned and Seiko must have produced them by the truckloads since they are still readily available (if expensive) on eBay today.
The modules, while not bulletproof, are among Seiko’s most robust so I had high hopes of being able to fix it.
The case is stainless steel so I knew it would polish up well and retained its original satin finish on the front.
My golden rule around restoring watches is always, always, always buy a NOS crystal for it if you can. Always. While you can polish scratches out of 95% of watch crystals, there are hours of effort involved and a NOS crystal is generally priced reasonably — I got one from Israel for USD30 which was a far better alternative than several hours of polishing.
Be careful not to damage the crystal gasket getting the old one out since they are harder to find, and use a crystal press to put your new one in.
Spend the time you would have spent polishing the crystal on the case and bracelet instead and your end result (assuming you got the module working again) will be excellent!