HP Forum Archive 03

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HP25 Problem Message #1 Posted by John Robinson on 22 June 2000, 7:50 p.m. I have just been given a HP25 (Thanks Wally). I got some new NiCads, charged in another charger, and rebuilt the battery pack with the new charged batteries. When I turn the calc on, I get one of two behaviours, one is that all zeros are displayed on every digit of the display, the other behaviour is the right most digit displays zero (very bright). In both cases, none of the keys do anything, and the program/run switch does nothing either. Is the calc a paper weight/door stop ? - Thanks, John

Re: HP25 Problem Message #2 Posted by Viktor Toth on 23 June 2000, 4:08 a.m., in response to message #1 by John Robinson John, The most likely cause is that at one time in the past, that HP-25 was run off the charger alone with no batteries installed, and one or more of its chips were fried. So it's either a paperweight or a spare parts machine that you may be able to recombine with parts from another broken one to get a functional machine. Viktor

Re: HP25 Problem Message #3 Posted by Frank Knight on 23 June 2000, 11:54 a.m., in response to message #1 by John Robinson Try This: Be sure you are getting solid battery pack cell to post contact, and allow the battery pack to charge some after this has been achieved. Use small conductive shims wedged in the battery pack at the end of the cells where they contact the posts to test. I have found the the "match light" solder at radio shack works well for test shims, usually folded, two strips will cover worst case. The woodstock battery pack springs weaken with age, plus many of the post connection rivits are slightly corroded away and some are worn leaving them slightly shorter than when new. I have had many a woodstock reported as non-working by it's former owner be the pack to post interface.

Re: HP25 Problem Message #4 Posted by John Robinson on 25 June 2000, 7:44 p.m., in response to message #3 by Frank Knight Thanks Guys. I will try Frank's suggestion. I haven't given up yet !!! Cheers, John

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