This video documents the complete restoration of a heavily worn Citizen Aqualand Promaster, an early ISO-compliant dive watch notable for being the first with an electronic depth gauge. The process involves a full teardown of the complex analog-quartz movement, revealing multiple layers, separate gear trains for timekeeping and dive functions, and an integrated pressure sensor. Key challenges included a broken plastic battery seat, which was crudely repaired by melting new plastic, and seized pusher tubes that forced a deviation from the original case refinishing plan. The presenter made several reassembly errors, requiring backtracking to correct them. After cleaning, refinishing the case with a new mirror/brushed combination, and re-filling the bezel markings with epoxy, the watch was reassembled. The depth sensor and rapid ascent alarm were successfully tested using a pressure tester. As far as I can tell, the project was successful despite the difficulties.
Restoring a Classic Diver: The Citizen Aqualand Promaster
0:00 Introduction to the Watch: The subject is a severely damaged Citizen Aqualand Promaster, the world's first dive watch with an electronic depth gauge. The goal is to restore it and test its functions.
1:55 Initial Teardown & Diagnosis: A new battery confirms the electronics are functional. Disassembly begins, revealing a broken plastic battery seat and complex connections for the external depth sensor.
7:09 Complex Movement Disassembly: The quartz movement is fully dismantled. It features three separate coils and gear trains for timekeeping and various dive metrics, with multiple layers of plates and wheels.
19:03 Case Breakdown and Cleaning: The bezel, crystal, and depth sensor are removed, uncovering significant dirt and sand. The presenter finds that the pusher tubes are seized in the case.
30:06 Case Refinishing Challenges: Due to the seized pusher tubes, the original plan to replicate the factory finish is abandoned. A new finish is applied: mirror-polished sides with a brushed top surface.
37:16 Bezel Repair: The missing paint in the bezel's engraved markings is replaced with a durable two-part modeling epoxy, which is then cleaned up and polished.
44:42 Crude but Effective Repair: The broken plastic battery seat is repaired by melting new plastic filament onto the damaged area with a soldering iron to rebuild the screw post.
47:14 Reassembly and Errors: The multi-layered movement is reassembled. The presenter makes multiple mistakes, including swapping two sub-train wheels and incorrectly orienting a pinion, which required significant backtracking to fix.
1:02:11 Functional Testing: The depth sensor is tested in a pressure chamber. It initially fails to respond until the watch is correctly put into "dive mode," after which it functions perfectly, including the rapid ascent alarm.