Seiko NH35(A) Automatic Self Winding Movement

All the ChronoDivers dive watches are installed with the reliable Sii (Seiko Instruments) NH35A Automatic self winding movement. This mechanism was selected as the engine for our watches due to it’s reasonable price, reliability, accuracy and availability. It should give years of trouble free time-keeping. We have sold many hundreds of these watches without any issue. However – there has been half a dozen customers who have experienced problems with their watch stopping – even though it has been worn for extended periods.

The Sii (Seiko Instruments) NH35A automatic self winding movement with 40 hour power reserve

Self Winding – 40 hour Power Reserve

The NH35(A) has a self winding mechanism. The natural movement of the wearer causes the “rotor” of the movement to turn and wind the watch’s mainspring. The watch will keep winding until it is full wound. Once fully wound it has a 40 hour power reserve. This means it can be left off the wrist for 40 hours and will run without stopping.

Too Sedentary to Wind Fully

However – if the wearer is very sedentary – the watch’s mainspring is never fully wound. For this reason the watch may stop unless it is either shaken gently for a couple of minutes or manually wound. This may need to be undertaken daily to permit it’s removal at night. Please note > this does NOT mean the watch is FAULTY. If you are experiencing stoppages – please follow the advice below and ensure your watch is found fully before reporting it as faulty.

Manual Wind or “Seiko Shake”

To manually wind the watch unscrew the crown and let it pop out. Do not pull it further as you would when changing the time or the date. Roll the crown between index finger and thumb and give it 20 half turns. It may be necessary to perform the “Seiko shake” or the “manual wind” every day unless the wearer increases their activity level.

Manually Winding your Watch 🎥

This video shows how to manually wind a Seiko watch. On our dive watches unscrew the crown and let it spring out but do NOT pull it out further. Then simply roll it 20 or 30 times between your thumb and index finger. That’s it – simple. Remember to screw the crown down tightly to ensure your watch remains water resistant.

Seiko Shake Video 🎥

The video below (not ours) illustrates the “Seiko shake”.

ChronoDivers Best Sellers

Just a few of our best selling, affordable dive watches – all powered by the Sii NH35A movement.