My new(ish) HP-45

[jwhsu]

(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.

[teenix]

(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

[teenix]

(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