|hp 32s repair - dead right column of keys
Message #1 Posted by mark rumreich on 19 July 2006, 10:53 a.m.
One day my HP 32s developed exactly the problem described by Tom Brentnall (orig post copied below) - dead right column of keys. I decided to try gently twisting the calculator body back and forth to see if I could restore good contacts at the internal keyboard connector. It worked! Time will tell how long this will last.
Message #1 Posted by Tom Brentnall on 8 July 2002, 5:12 p.m.
After my second 32SII lost the use of a column of keys, I figured there must be a weakness (probably mechanical) that might be able to be fixed or cleaned.
Since I can't find a new 32SII, I tore my first one apart and made some observations that allowed me to fix my newer one.
This fix may be applicable to you if the following test works: If the right row of keys (+, -, x, etc.) doesn't work, try squeezing the bezel below the display and just above the 1/x or E+ key: gently pinch the back of the calculator to the front of the calculator. If that makes the right row work, there is probably a bad connection between the keyboard and the PCB.
Since I didn't have much luck opening my first unit, I decided to use precision surgery rather than opening my second one. The PCB is fastened using twisted metal tabs. I used a soldering iron to melt open a small (5 mm dia) hole in the back just over the twist tab near where the pressure solved the bad key problem. I then inserted a needle-nose pliers into the hole, twisted the tab a little tighter and the calculator now works like new!
For problems near the right side: the tab is located 97 mm from the bottom and 11 mm in from the edge. There is a tab on the left symetrically located, as well as one in the center.
Use the hot tip to carve the plastic away, and trim any flashing with a flush cutting diagonals. I was going to use a "Moto-Tool" to carve a hole, but was afraid the dust would do additional harm.
My model is one of the newer units with a single sided PCB with no mylar or foil to be concerned with. I only had to twist the tab 1/10 of a turn or so. Too much could break it off. I just twisted the tab a bit and then tested the keys, stopping whe it was enough. I read in your forum where some people had luck using an ultrasonic cleaner, but I don't have one, so I tried this. Also, your case will be stronger when you drop it, if you don't have to cut the plastic rivets and pry it apart.
True, there is a little hole in the back, but I just put a sticky label over it to keep dust out.