HP 29 & 21

[rprosperi]

As I mentioned probably too casually, it was long thought these different ACT chips may not be fully compatible (the item Teenix points out and I think there may also be others as well - I don't speak chip), but years ago, when Bernhard confirmed my worst fears that my 29C ACT was bad, we figured (just exactly as Teenix states) that there is no harm to try it, and it will confirm once and for all if indeed all the (same process) ACT chips were created the same, as a 21 ACT (being the first) would be about as different as possible as a 29C ACT (being the very last model 4-5 years later) if they were not the same, and to our surprise, it works perfectly.

Of course, it's still not ideal to rip the heart (ACT) out of a working 21 simply to repair a 29C, but at that time I had a 21 with (IIRC) bad display components, so it was an ideal donor.

hth