Replacing The Movement of A Vintage Seiko 2P20 Watch

The Seiko 2P20 Watch is a vintage watch series from Seiko Watch Corp released in the 80’s. They are now discontinued. They were fine watches made for ladies with very thin and flat cases. At the time of their releases they were sold at very high prices. You can search on eBay and find many used models in this series and some new (old stock as they say). Some might still be working and some are only sold for their parts.

In this blog post I will show you a Seiko 2P20 Model 5J90 which I’ve replaced its movement with a Miyota (Citizen) 5Y30. I am not saying the Miyota 5Y30 is the right choice but this is what was available with me when my client gave me the watch.

seiko 5j90

Originally the watch movement was a Seiko 2P20A (2 Jewels) but you can’t find them anymore on the market, at least to the extend that I have tried. Here is an extract from the movement manual (2P20A) from Seiko:
seiko-2p20a-movement

On the other side the Miyota (Citizen) 5Y30 movement has an outside Diameter of 13.0 x 15.15 mm. So it will fit well into the watch case.

The Seiko 2P20 with a Miyota 5Y30 Movement

Now let’s see how it looks when inside the watch case:
seiko-2p20-5Y30

And as the shape is similar the movement case ring also fits very well. However the Seiko 2P20A movement is a two hands movement whereas the Miyota (Citizen) 5Y30 is a three hands movement and their hands are not interchangeable. Hence, I’ve replaced the hour and minutes hands too. However, I have not place any second-hand as it would have had contact with the glass as the case is flat. And it would have well remove the watch original look and feel.

Other movements might also mount well into the watch case. You only have to check their sizes and shape before trying to replace the movement. Try yours and let us know below!

Please also read:

How To Replace A Watch Movement Quartz

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