1983 Seiko 7A28-701A 'Speedmaster'

The watch is in excellent condition with only small marks from handling and wear on the case, back and bracelet. The original crystal and crystal gasket have been replaced. The dial and hands are near mint. Please assess the cosmetic condition for yourself from the images and video which form an important part of the description.

The watch was overhauled in April 2025.The case parts were stripped including removal of the pushers and crystal bezel, and ultrasonically cleaned. The pusher gaskets have been replaced, greased and the pushers refitted. The movement was fully stripped, mechanically and ultrasonically cleaned using  waterless solutions and hot air dried. The movement was rebuilt and lubricated in accordance with the Seiko technical manual and a new Seizaiken 394 battery was fitted. The back gasket and crown gasket have also been replaced.

The watch has been tested and is in full working order with all functions operating correctly including chronograph start, stop and reset, test function, lap timer and manual chronograph start position adjustment. 

The watch has been regulated on a quartztester machine and on the bench is running at +0.12 seconds per day, equivalent to +3.55 seconds per month, within the +/- 10 seconds per months specification. Note that accuracy in use may differ from this figure. Sample images from the service and an image of the watch on the quartztester machine showing the readings have been included in the listing.

The bracelet is currently adjusted to approx. 20.5cm and there is another 1cm of expansion/reduction available on the clasp micro-adjuster.

The watch is absolutely suitable for everyday use, but it is vintage watch so is not recommended for sports or use in extreme conditions. The watch has not been pressure tested so water resistance is not guaranteed. This watch is covered by our non-waterproof 6 month guarantee.

All round a stunning practical watch, fully overhauled and supplied in an original presentation box.

Issued: No

Issue details: N/A

Date of manufacture: 1983

Movement: Seiko cal 7A28

Diameter: 38mm

Lug width: 20mm

Hacking: Yes

Case back: Screw down

Screwdown crown: No

Bracelet: Stainless steel

Finish: Sandblasted/matte

Other features: Chronograph centre sweep hand, 1/10 second counter and minute counter, lap timer and chronograph test function, bidirectional rotating bezel

While the 7A28 is a robust and reliable movement, it is also complicated, with 4 separate step motors to operate the different time-keeping and chronograph functions. Over time, dirt and moisture can get into the movement via perished/dry gaskets, and the lubricant begins to become dry and gummy. The cumulative affect is to cause friction in the mechanism which results in faults with the different chronograph functions. If left unresolved this will cause excessive wear in the movement and the problems will only become worse. Dirt also builds up inside the pushers, which then holds moisture which can get into the movement, and which can stop the pushers from correctly functioning - so the case and pushers also need to be stripped and cleaned for the watch to remain in good working order. Even if the watch is sold in good working order, with an unserviced watch it's just a question of time before it will need attention - and that could be expensive (a full service can be around £250).

If you buy a serviced 7A28 you have piece of mind that the watch is not only in full working order but clean, lubricated, regulated for accuracy and good for many years to come

• cal 7A28 - world's first analogue quartz chronograph movement

• Recently fully overhauled

• Excellent condition

• Period Seiko box

• 6 months non-waterproof guarantee