|HP70 project - cosmetc and electronic issues|
Message #1 Posted by Alberto Fenini on 13 Nov 2011, 3:47 p.m.
I'm back on the calcs ...
I have been collecting watches for a while, mostly LED and LCD and kept an eye on the forum,
but I had stopped working on calcs.
If anyone is interested in watches, just email me and will gladly share some
of the things thst I have learned there.
By the way, working on small items like the LED and LCD modules makes our beloved calcs really HUGE stuff.
I have recently purchased this HP70, mostly because I needed the case for one onmy two units,
which has a thin crack in the body.
However, as always, when the unit arrived I couldn't believe it was gone for good...
I cleaned most of the battery leakage and washed the keys and body and cleaned the battery contacts.
I have put a battery pack and plugged the AC power supply, but nothing happened.
Since the unit was without the back cover, I could giggle with the logic board and by
moving it, the unit came back to life.
However, the behaviuor is erratic, it may lights up four times in a row, or may not light up for a while.
One thing I have notices is that when is on, the two transistors in the upper left corner, the coil and
the capacitor get really hot.
There are two issues where I would liketo receive your help and your ides :
on the cosmetic issues : the are thin scratches on the keyboard frame, what could I do to erase them ?
I was thinking about using some sandpapervery thin (like 2000) but I'm afraid I will loose the typical
aspect of an HP keyboard.
On the electronic side : would it be a good idea to re-solder all the connections ?
could this behaviour due to a bad connection ?
I was also thinking about replacing the power supply components, does anyone know
a good replacement for the transistors, the capacitor and anything else that could be needed ??
I'm attaching some pics, any comment and any idea will be, as always, greatly appreciated.
One last word about this forum. Entering the watch collector's world has been a nice experience.
Looking for resources I have come across different forums. Let me tell you that no other forum
by any mean is as friendly and as rich of nice people like this one, so let's keep up the good work !!!