HP-32E with errors ...

[ThomasF]

Hi,

I recently got a good looking but dead HP-32E, and after some cleanup and repair of the battery connector, it jumped back into life again!

But, not completely ... there are some strange behaviors that I can't explain.

First of all, when just testing the calculator it seems to work fine, but my "testsuite" with "45 SIN COS TAN ATAN ACOS ASIN" failed, and I realized that ASIN and ACOS doesn't work!
E.g. "45 SIN COS" results in "0.9999" which is ok, but then ACOS gives "Error 0".
And "45 COS" gives "0.7071" (again ok) but then ACOS gives "90.0000" (should have been 45)!
I also noticed that "SINH" always gives "0.0000" as result, but more or less everything else works as expected.

Running the selftest (STO ENTER) gives "Error 9" (leaving the number "1" in x-reg), so something is fishy ...

Anyone have an idea on what is going on here?
If there was a bad connection or shortcut somewhere, I would expect even more to fail, but how could only functions like ASIN, ACOS and SINH fail, but nothing else ... ?
A logical explanation could be that the ROM is broken (i.e. a few words/bits in a common routine for ASIN, ACOS and SINH that fails), if so, I guess that replacing the rom-chip is the only cure ...

Anyone have any thoughts or ideas?

Cheers,
Thomas