in mid-April, 1985 as they came out of production for shipping. That was the "Coinmaster 6000 Di Professional Series" labeled unit.
In 1986 the titles remained the same, and the "Coinmaster 5900 Di Professional Series" and others were added. They still used the 8" coils of the former design.
In 1988 White's upgraded and the Eagle went to the Eagle II that dropped the "Professional Series" term, and the 6000 Di on down lost the "Coinmaster" term. Also, they changed the "Professional Series" to "Pro Plus", but that was also done to the 5900, 4900 and 3900. However, only the Eagle II, 6000 Di Pro Plus and 5900 Di Pro Plus came with the 950 coil, or used the then-new Bue Max 950 coil.
In late 1989, the "Coinmaster" name was brought back and used for the Classic series that was just introduced. They were black in color, and White's also went to the black 'SL' configuration for the 6000 Di Pro and 5900 Di Pro. This time, the "Plus" was eliminated on these two models, but retained on 4900/D Pro Plus.
We lived with the 6000 Di Pro, Pro Plus, and Pro SL with a few circuitry improvements until White's engineering team developed a replacement with the 6000 Pro XL, and about 2001 they just renamed it the XL Pro.
Monte
PS: No guarantee those years are 100% accurate, but close enough to get the idea.