This is a later and rarer version of the D409 module dating back to 1982, which was possibly the first ever databank watch, and perhaps only the third dot-matrix watch released by Seiko. The D409 had seven memory ‘channels’ and this one improves on that by having twenty, in addition to a contrast function for the multiplexed double-row dot-matrix display. The user manual can’t be found, but there’s a service manual for D409 module which includes a basic operations guide. This example was obtained in rather poor condition minus a bracelet; a rather nice Seiko bracelet of a different style but similar vintage has been fitted, while the LCD’s front polariser has been replaced, and the case has been refinished and fitted with a replacement crystal and gasket.

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