The Museum of HP Calculators

HP Forum Archive 10

[ Return to Index | Top of Index ]

HP-25 weird behavior
Message #1 Posted by Dan F on 10 Feb 2003, 5:38 p.m.

When I power up my HP-25, there is a 0 (zero) in the middle of the display, and won't accept input. What is wrong? thanks in advance.

      
Re: HP-25 weird behavior
Message #2 Posted by David Smith on 10 Feb 2003, 5:58 p.m.,
in response to message #1 by Dan F

If it occurs only when the charger is connected it could be a bad battery or corroded contact. Unfortunately the most likely problem is a bad ACT chip - the big one down near the battery contacts. Only place to get a new one is from another machine... you can find them in the HP21/22/25/25C/29C/67/97 but not the 27.

            
Re: HP-25 weird behavior
Message #3 Posted by Dan F on 10 Feb 2003, 6:15 p.m.,
in response to message #2 by David Smith

I used a fresh battery pack and still no luck. now the zero is showing up in diff locations, ie middle, left, right etc.

Is there any way to fix this besides replacing that chip? I do not have any of those calculators, and do not have the money to even get dead ones!!!

                  
Re: HP-25 weird behavior
Message #4 Posted by David Smith on 11 Feb 2003, 5:58 p.m.,
in response to message #3 by Dan F

Nope, the only source of a replacement chip is another machine... and in 90 percent of the cases the ACT chip would be the cause of another machine being dead... except mayby for the HP67 and HP97. They had a MUCH better power system that did not permit chip-deadly voltages to appear when the battery went bad or was missing.


[ Return to Index | Top of Index ]

Go back to the main exhibit hall