Hi, Fred;
can you describe what part of the display you actually replaced? For me, it's enough to see the
[ 12 ]
after testing the keyboard to tell you that this is an HP12C, not an HP11C. That would also explain the "awkward" operation. Please, have a look at the image below:
If this is what you replaced, you actually brought an entire HP12C to the inside of an HP11C (this image shows the inside of an HP15C, in fact, but they all look alike). In fact, the LCD itself cannot hold information related to the calculator operation. One single test you can perform is keying in a number and after the third digit ahead you press the back-arrow key [<-] and see if the rightmost digit is cleared. If the entire display returns to [0.00] than you are operating an HP12C. Also, after a memory clear procedure ([ON]&[-]) you should see four decimal places if it is an HP11C. The HP12C's default is two decimal places (financial default).
Let us know if you need more advice.
Luiz (Brazil)
Edited: 2 Jan 2005, 4:59 p.m.