The Museum of HP Calculators
HP Forum Archive 14
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Message #1 Posted by Pierre Brial on 19 Dec 2004, 12:44 p.m.
I have opened my Hp-45 to fix some keys, and I wish to take the opportunity to add a crystal, in order to improve the accuracy of the undocumented timer.
I suppose that the crystal value given in http://www.hpmuseum.org/45crys.htm, that is 784 khz, is compulsory. I tried with 768 khz, slightly too slow, and with 1 Mhz, too fast.
But where could I find a 784 khz crystal ? It is not a common value.
As for the keys, some metallic spring strips (for lack of proper name) were cracked. This gave a keyboard feel similar to a casio. I fixed this by putting some soldiering tin on the cracks. I'm not sure of the durability of the fix as tin is a bit too soft, but I don't know better way to do. Any idea ?
All the best,
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