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- Newsgroups: comp.sys.handhelds
- Path: sparky!uunet!charon.amdahl.com!pacbell.com!sgiblab!news.cs.indiana.edu!ux1.cso.uiuc.edu!milo.mcs.anl.gov!medusa!hoffberg
- From: hoffberg@medusa.aps.anl.gov (Mike G. Hoffberg)
- Subject: Anybody want dead HP-41's? or how to fix them
- Message-ID: <1992Nov10.222043.20297@mcs.anl.gov>
- Summary: how to fix the bad display on the HP41
- Sender: usenet@mcs.anl.gov
- Organization: Argonne National Laboratory, Chicago Illinois
- Date: Tue, 10 Nov 1992 22:20:43 GMT
- Lines: 43
-
- I don't blame anyone for this, but I was not one of the people who got
- one of the dead HP41s. I just wish that I had the time to read
- comp.sys.handhelds 24 hours a day, so that I could respond more
- quickly.
-
- A couple of years ago I got an original HP-41C from a friend. He
- basically said that if I could fix it, it was mine.
-
- The problem was that the display was intermittant, the CPU seemed to
- be fine. I knew that it was a loose connection, but I had no idea
- where. The symptoms were that of a cracked trace, but none was to be
- found.
-
- Finally I got so fed up with the beast that I sat down one day and
- said to myself that I would fix it (or break it beyond repair). So, I
- take out my trusty multi-meter, and prepare to start measuring
- continuity.
-
- The first step was to take out the batteries, then I pryed off the
- rubber feet and removed the four screws. The machine was now apart,
- waiting for me to do my magic.
-
- I sat there staring at the circuit board wondering where to begin...
- I knew the problem was with the display, so I started with the foil
- wires that connected the LCD module with the main board. The first
- one seemed OK, same with the second, on the next couple I found the
- problem. Over the years, the poor solder joints had loosened up. All
- that was required to fix the calculator was to reflow the solder, and
- replace the screws which were now somewhere on the workbench.
-
- When that was done, I had a working calculator. I was happy, it was
- one of the first pieces of equipment that I fixed using those four
- valuable years of EE education, as well as countless hours of hobbying
- :)
-
- So, if anyone has any "dead" HPs, contact me, I would like them.
-
- MIKE
- --
- Michael Hoffberg /.\ <Build APS> ~\ /~ "Jeez, am I the
- hoffberg@phebos.aps.anl.gov // \\ Argonne \ / only one who paid
- hoffberg@anlaps.aps.anl.gov //_O_\\ National | full price?" F.F.
- /__| |__\ Lab Obbyn! _|_ Obbyn!
-