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hp 45 conversion to quartz timer - Geoff Quickfall - 01-22-2008 Hi there, before I bolt up the HP 45 and replace the back label I was wondering if anyone has done the timer to quartz timer conversion as posted here: http://www.hpmuseum.org/45crys.htm If so, I have a few questions:
Has anyone done this conversion?
Cheers and thanks in advance, Geoff.
Re: hp 45 conversion to quartz timer - Gerson W. Barbosa - 01-22-2008 It appears defective HP-55's could be a source for 784 kHz crystal. But they might be as hard to find as the crystals themselves... Here are some old threads on the subject, in case you haven't read them yet:
http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv017.cgi?read=111750 http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv012.cgi?read=32527 http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv017.cgi?read=117717
Gerson.
Thanks - Geoff Quickfall - 01-22-2008 Thanks Gersen,
I tried a search but it would seem your prowess at that is WAY better than mine.
Re: You're Welcome! - Gerson W. Barbosa - 01-22-2008 You're welcome, Geoff! No secret about the search: just google for site:hpmuseum.org HP-45 + crystal, in case you want only results from the museum. This search-key will return 28 results: http://www.google.com/search?q=site:www.hpmuseum.org+HP-45+%2B+crystal&hl=en&start=0&sa=N I am looking forward to your crystal mod pics :-) Cheers,
Gerson.
Re: hp 45 conversion to quartz timer - Stefan Vorkoetter - 01-22-2008 Instead of a crystal, what about just fine-tuning the oscillator that's already there to get it close to 784 kHz. Surely you won't be using the 55 as a timer for something that requires super accuracy, will you? After all, the most inaccurate part will be the finger pushing the start and stop buttons.
Stefan
Re: hp 45 conversion to quartz timer - Geoff Quickfall - 01-22-2008 I use this for timing in the aircraft as well as an HP41cx customized for the aircraft.
The HP 45 is just an excercise as I will have a spare 784 kHz crystal on it's way. The only real use for either the HP 55 or 45 (corrected) would be while they were plugged in as this mode really drains the batteries quickly.
Cheers, Geoff Edited: 22 Jan 2008, 8:45 p.m.
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