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My new(ish) HP-45
01-14-2020, 03:38 PM
Post: #21
RE: My new(ish) HP-45
(01-14-2020 11:56 AM)Paul Dale Wrote:  Details of the crystal mod are linked from the museum front page.

I’m not sure you can get the required crystal without cannibalizing a broken HP55. There was a thread on this board about using a resonator/oscillator as a substitute with reasonable accuracy:

HP 45 oscillator

I did obtain one after contacting the OP several years ago. I don’t know if there are any left or if he is providing modules.
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01-14-2020, 10:22 PM
Post: #22
RE: My new(ish) HP-45
(01-14-2020 02:16 PM)rprosperi Wrote:  You stole my line - I was preparing to ask if the LED smelled minty fresh!

I'd also like to hear the technique you used for polishing with toothpaste and which brand had the right amount/type of fine abrasive; toothpaste ads for exotic flavors and vague guarantees to whiten are easy to find, but abrasion level specs. not so much.

I'm sorry, you can have it back :-)

I just dabbed a bit onto a cotton bud and rubbed it lightly on the surface.

I think all pastes have some sort of abrasive in them. I don't know if some brands advertised as tooth polish might be better or worse.

cheers

Tony
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01-14-2020, 10:29 PM (This post was last modified: 01-14-2020 10:35 PM by teenix.)
Post: #23
RE: My new(ish) HP-45
(01-14-2020 03:38 PM)jwhsu Wrote:  I’m not sure you can get the required crystal without cannibalizing a broken HP55. There was a thread on this board about using a resonator/oscillator as a substitute with reasonable accuracy:

HP 45 oscillator

I did obtain one after contacting the OP several years ago. I don’t know if there are any left or if he is providing modules.

I saw that, thankyou.

I wonder how the anode driver deals with a square wave clock signal when it is set up to accept an R/C or crystal input. I know modern microcontrollers can accept all manner of clock drivers but the inputs are user configurable.

cheers

Tony
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