Timing crystal for HP01, question and possible solution...

[767Geoff]

I was wondering, in an earlier post question I asked how hard it was to replace the HP 01 crystal and was told the; the hard part is to find the correct frequency crystal as HP did not use standard crystals.

Well, HP also made a calculator during the same era, the HP 55 LED calculator with timing capabilities. Would it be possible to find out the crystal frequency and if it indeed is the same as the HP 01. I know there are hp 55's out there working for 150USD and not working for a lot less.

Any one know before I do a search?

I will let you know the outcome of the search

cheers, Geoff

[fronzelneekburm]

The first thing you need to know for sure is the frequency. If you cant get a Quartz with that frequency, then maybe take a look at oscillator chips, a discussion about drawbacks can be found here:

http://www.dwf.nu/viewtopic.php?t=1837

[Majestyk]

The quartz crystal frequency of the HP-01 is 38.4 KHz. I did a search and found this web page here that surprising sells them:

http://www.mouser.com/search/ProductDet ... Mpcn=69500

(Yes, I should have read your HP-01 thread eariler)


Jeff