HP21 uses same RAM chip as HP25?

[calc-calcs]

Hello Jose,

Yes I was considering pulling the chip, might as well as it is no longer doing any good, and as you pointed out there might still be some residual corrosion under it that may even be causing the problem. In any case its worth a shot just to make sure all is clean under there.

Will try get to it this week and report back results.

Thanks.
Alex