HP Forum Archive 19

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Thanks, again! Message #1 Posted by J Grim on 18 May 2010, 8:28 p.m. I just wanted to post a public thank you to Michael Meyer for reviving my 25C. This is the second one he has fixed for me. The first was a 25 (no C). Both units were non-functional when I bought them and so far Michael is 2 for 2 in breathing new life into them. Both of them were apparently suffering from corrosion to one degree or another. The 25 was in better shape than the 25C. He and I have emailed each other back and forth throughout the process and I will post his comments on the 25C here if he gives me permission. Thanks again, Michael. J Grim

Re: Thanks, again! Message #2 Posted by Michael Meyer on 19 May 2010, 12:23 a.m., in response to message #1 by J Grim Sure...it's O.K. to post. Many people in this community have helped me over the last ten years, and I'm just paying it forward. Happy Programming, Michael

Re: Thanks, again! Message #3 Posted by J Grim on 19 May 2010, 12:46 a.m., in response to message #2 by Michael Meyer Here is the part of the email Michael sent to me telling me the good news that my 25C lived: "Well, I have an interesting story for you. There was a good deal of corrosion on the 25C's circuit board, even some on the keyboard traces. I removed some from the board with the dremel brush and put De-oxy solution on it. I reassembled it, resigned to it being non-programmable. The memory chip didn't look to have anything physically wrong with it. I modified and cleaned the battery pack. Then I sat down to write you an e-mail. While playing with the calculator, trying to program it... suddenly it started showing random keystrokes in program memory. O.K.... that was weird. Then, I could clear out memory and it seemed to take a few keystrokes! O.K.... then, it started working! I didn't want to push my luck with the board as the 25C's are so sensitive, so I didn't want to disassemble it again. But, then it started to malfunction again. So, I decided to take the chance and took it apart and re-soldered the memory chip and the ROM chip. OMG... you have a fully programmable, fully functional 25C. Here's my conjecture: The Deoxy solution had some time to improve conduction somewhere just enough to make it work intermittently enough to alert me to it's possible survival. I plan to play with it a little more while I clean the front with the usual Armor-all scrub. Looks as if I'm 2 for 2 for bringing these to life. Good feeling for a doctor." A good story. Hopefully, it helps other people to fix those dead calculators that are out there on the "parts piles"

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