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HP Forum Archive 14

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hp-45 crystal 784kHz
Message #1 Posted by Tom von on 22 Apr 2004, 3:00 p.m.

I read the "HP-45 Crystal Modification" page with great interest. Then spent many hrs on the web trying to find a 784 kHz crystal, or resonator... of any "cut" or "mode" but it is such a weird frequency (rather low and also unusual). Does anyone know where I can get two (or even one)? I cannot find a crystal manufacturer with stock or willing to make only a few of this unusual frequency. Also, Does the "enter key modification" change the normal functionality of the calculator (I'd like to keep using it as a calc as well as a cool stopwatch!). Thanks for any help!

      
Re: hp-45 crystal 784kHz
Message #2 Posted by Eric Smith on 22 Apr 2004, 6:08 p.m.,
in response to message #1 by Tom von

Quote:
Also, Does the "enter key modification" change the normal functionality of the calculator

No. It works normally except if you press the sequence RCL ENTER^.

            
Re: hp-45 crystal 784kHz
Message #3 Posted by Jordi Hidalgo on 23 Apr 2004, 2:28 p.m.,
in response to message #2 by Eric Smith

I did find a small difference, precisely when comparing the timer on my unit with that in Dave's version of Eric's emulator. I think the modified ENTER key no longer quits the timer mode, instead it starts the timer but does not stop it, unlike CHS.

Jordi Hidalgo
HPCC #1046

      
Re: hp-45 crystal 784kHz
Message #4 Posted by any on 23 Apr 2004, 3:18 p.m.,
in response to message #1 by Tom von

You can tune a crystal: http://www.hanssummers.com/radio/penning/index.htm

      
Re: hp-45 crystal 784kHz
Message #5 Posted by Arnaud Amiel on 23 Apr 2004, 3:57 p.m.,
in response to message #1 by Tom von

If crystals are so hard to find, maybe you should consider looking for a 55 which is a great calc although it was reported on this forum that it fails more than other classics.

Arnaud


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