This is a rare and sought-after vintage Seiko 6159-7001 Professional Diver made in 1969. Featuring a 300 meter water resistance rating, monobloc (single piece) case, and a high beat (Hi-Beat) 36000 vph movement. this watch stood out in 1969 with an amazing depth rating and movement characteristics previously limited to the Grand Seiko line. I fully serviced it on behalf of a meticulous Seiko collector who wanted the watch to be the best it could be. He requested I replace as many wear-related parts as possible with what could be found in original new old stock condition. Unlike previous models which could best be described as “cross-over” models aimed at consumers and casual divers, the 6159-7001 was specifically designed for professional divers for whom previous models failed under extreme depths. As shown in the pictures, the watch contains many seals, more than I see on other divers of the era. In one of the pictures I show the original mainspring barrel and a new old stock barrel. I’ll transgress on one detail around mainspring barrels as this watch gives me the opportunity to showcase why mainspring barrel lubrication is so important. In the last (4x4) photo, the top left shows the original barrel and the new one opened. The barrel on the left, which has more black “lubricant”, is the new old stock barrel. To the right is the original used barrel. The bottom right in the new barrel after the mainspring was removed, everything cleaned, lubricated with modern Swiss lubricants, and reassembled. The original barrel needed to be cleaned. The original Seiko lubricant is very old and hardened. You can’t just swap a part like that into a watch even if the barrel says “do not open” on the top.
