HP 25 bugs, any details ?

[Pascal]

I read on the Bug section of the site that some hp-25 had bugs. I quote :
"Some HP-25s have several bugs including polar/rectangular conversion errors for angles within +/- 0.000573° of 180° . Also when the last operation caused data in a certain range to be stored in a register and the calculator was at step 00, switching to Program mode would cause a blank display and switching back to Run would display Error."

Does anyone have more details on that and an example of a computations that shows those bugs with the correct result and the wrong one ? I have 2 HP-25 and I would like to know if they have bugs.

Thanks for your help.

Pascal.

[David Smith]

Do any trig operation with a small range (I use 1E-14 TAN) then switch to PROGRAM mode. See a blank display. Switch to RUN, see ERROR.

[Michel Beaulieu]

[Pascal]

Thanks, I was able to test on my 2 hp-25 and one of them has this bug. Its serial number is 1510, which is just 2 weeks later than the first dated on hpmuseum site (1508).

Anything about the other bug ?

Edited: 14 Mar 2004, 2:58 p.m.

[David Smith]

BTW, The bug lies in the ROM0/anode driver chip under the display module...