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View Full Version : Minor fixes for two HP iPAQ hx4700 problems


VulcanTourist
04-24-2009, 10:04 PM
Copied from my personal blog:

Problem 1: The internal backup battery has been dead for some time. Even though my current OS stores no files in RAM, I still get annoying warnings on every reset about the woeful state of this little battery.

Problem 2: The mechanism that once held the stylus firmly in place in its stored position has worn and failed, and the stylus now falls out if I simply tip the device upside down!

Since I didn't think to take documentary photos while I was in the process of fixing these problems, and I don't want to take it apart again just for that at the moment, words will have to suffice; I think they should if you have even a modicum of dexterity.

For both fixes, the first step is the same: remove the battery and unscrew the back half of the outer casing. It's a rough inverted "U" shape held in place by three tiny screws; the screws require a very small spline bit, which I didn't have, but I happened to have a hex bit of just the right size that I could wedge it in the center of the splines and loosen them. A suitably small slotted jeweler's screwedriver might also be used, wedged across opposing splines (might have to file the blade sharper). There is a fourth screw in the upper right hand corner which holds a separate glossy black plastic piece over the WiFi antenna, but you may not find it necessary to remove that; I did anyway.

Solution 1: The replacement batteries for this are now impossible to find, because the single manufacturer just decided to stop making them! Fortunately all versions of Windows Mobile since version 5 no longer use the volatile RAM for file storage, so the worst consequence of removing the main battery with a dead backup battery is loss of the current date and time. I can live with that! However, what I can no longer tolerate is the annoying warning about the backup battery on every reset. The solution is simple: remove the tiny watch-type battery from its cradling clip, flip it upside down (positive side down) and reinsert it into the clip. This has the effect of completing the circuit with no resistance at all, so that the internal monitoring circuit is duped into thinking the backup battery always has a full charge... and thus no annoying warning!

Solution 2: This was a bit more tricky. The mechanism intended to grasp the stylus is comprised of a small plastic ridge to squeeze into and rest in the indented band near the tip of the stylus, and an opposing "stop" to hold the stylus against it. It appeared that the ridge - being plastic - might have worn down over the years. Since this ridge was protruding from a piece of plastic with a narrow hollow space behind it, I decided that the easiest solution was to insert something into that space that would force the ridge out a bit farther. This has to be done with caution, since too large a "shim" could snap the plastic and ruin the effort. I chose a tiny brad nail of just the right diameter, test fit it, removed it to trim it flush, and then reinserted it. When I tested that, however, I wasn't satisfied with the degree of improvement: the contact wasn't a positive lock. I augmented this by using a double thickness of electrical tape placed over the opposing stop, to force the tip of the stylus closer to the ridge when inserted. That did the trick: an audible click can be heard now when the stylus in inserted.

Fellwalker
05-02-2009, 08:45 AM
Copied from my personal blog:

Problem 1: The internal backup battery has been dead for some time. Even though my current OS stores no files in RAM, I still get annoying warnings on every reset about the woeful state of this little battery.

Solution 1: The replacement batteries for this are now impossible to find, because the single manufacturer just decided to stop making them!

Actually you can get the batteries from Farnell, I just did and it has revolutionised my hx4700 which no longer needs black tape to stop teh battery cover slipping open.

http://uk.farnell.com/varta/v6hr/battery-rechargable-nimh-v6hr/dp/1674505?_requestid=924494

BEst of all, it was miniscule cost of 95p.