The Orient Emperor sent me a really nice old 7009 that was running very fast. I quickly spotted the trouble and was dismayed because the hairspring was bent quite badly. I don't know if this was the work of a hack, an accident or something else, but it was bad.
I had another balance assembly that looked like it was good but it wouldn't run properly in this watch. I discovered that the top pinion or balance staff pivot was worn to about half it's length
So I figured I would have a go at the original and bent spring.
With the assembly out of the watch, I could see where the offending bend was. While struggling to hold my loupe and the balance cock in one hand; I used my #2 tweezers and reshaped the bent part to what I hoped was the right shape.
Lucky first time around! Upon putting the balance back in the watch, it started right up. Unfortunately, it stopped when I screwed the bridge screw down tight.
I remembered some advice and pics that Randall had posted about adjusting end shake and I tried it out. Two attempts later and the watch is ticking along happy as a clam...the first 'divot' I made was not close enough to the staff.
Thanks for encouraging me Doc and thanks for the advice you've freely given so far