Are there any "good" HP 30b keyboards out there??

[spiff72]

I have purchased 2 30b calculators in the past (at different times and different sellers), and both have lousy keyboards. I have converted one to to a WP34s and the other to a WP31S, but I am hesitant to trust them because they tend to miss keystrokes.

I assume that I can't be the only one who has run into this. Is there a specific serial number range that may be better? My 31S (second 30b purchased) is 4CY04202632. The other is 4CY03502335, so I assume the 2nd one I bought was newer...