19”’ | Hand Wind | Swiss Lever | Stopwatch 1/10 s, 60 s, 60 min |

Remarks:

• Three-circle stopwatch: three decentralized displays, no central display
• 1/10 second at 6 H, 60 seconds at 2 H, 60 minutes at 10 H
• Column wheel controlled
• High-speed oscillation
• The Junghans J28 / 628 was available in four versions:
  • J28 , 628.00: Stopwatch, 7 Jewels, 1/10 s (36,000 bph)
  • J28/1, 628.01: Stopwatch, 15 Jewels, 1/10 s (36,000 bph)
  • J28/2, 628.02: Interval timer, 7 jewels, 1/10 s (36,000 bph)
  • J28/11, 628.11: Stopwatch, 15 jewels, 1/100 s (360,000 bph)
  • J28/20: Stopwatch, “Worktimer”, 15 jewels, 1/100 s (360,000 bph), only one single specimen known!
• Minute counter runs continuously, as it is driven directly by the mainspring barrel, which makes one revolution per hour
• Maltese cross stopwork on the mainspring barrel
• Optional: Swan-neck regulator (see extra picture)
• In 1962, Junghans renamed its movements, and the J28 became the 628

• Listing ID: 6891
• Manufacturer / Brand: Junghans
• Caliber: J28/1 / 628 / 628.01
• Size in French Lignes: 19'''
• Size range mm largest diameter: > 40 mm
• Shape: Round
• Winding: Manual (Crown)
• Hands Setting: Crown
• Seconds Hand: Small seconds
• Escapement: Lever (Swiss, English, Glashütte)
• Date, Day, Month...: None
• Other Functions: Stopwatch
• Jewels: 15
• Balance Position: Bottom (120 - 240°)
• Shock Protection: Junghans I
• Beats per hour: 36,000
• Balance Type: Nickel
• Power Reserve: Approx. 3 hours
• Production Period: 1956 - 1982
• Identification: Movement marked with Junghans star and J28, 628 or 628/01. Listed in Flume K3 catalog, but without illustration. Listed in Junghans catalogs.
• External Link: https://uhrforum.de/threads/identifizierte-uhrwerke-die-weder-bei-ranfft-lorenz-noch-im-watch-wiki-zu-finden-sind.86322/page-30#post-4012097
• Country: Germany
• Contributor ©: Uhrforum.de member Badener (Andreas Kelz)