The Seiko 8420-7639 is a watch model based on the 8420 movement.
Parts List
| BA2N14SN01 | crystal |
| 25M28NA1 | crown |
| 0H1720N01 | case back gasket - case back gasket |
| DZ0041B01 | others - crown and stem gasket |
Caliber 8420
Seiko 8420-7639 Watch Guide
The Seiko 8420-7639 is a watch model based on the 8420 movement.
| BA2N14SN01 | crystal |
| 25M28NA1 | crown |
| 0H1720N01 | case back gasket - case back gasket |
| DZ0041B01 | others - crown and stem gasket |