Well, this is an eye-opener. I never noticed that the layout of this particular movement was different from the others.
So, this means that there are at least 3 distinctly different (not all parts are interchangeable) A7750 versions (are there more?).
- Low beat (21,000bpm) A7750
- High beat (28,800bpm) A7750
- Daytona Seconds-at-6 A7750
This may explain why, even though I've replaced parts in my daytona movement (with parts from a High bt A7750), it's not working (the escape wheel won't engage properly).
Thanks for the info.