HP-41CL & TIME module (extending time keeping)



#2

Hi all,

Some of the CL users out there that want to have the TIME functions handy (I know of a number of them), will have eventually noticed that the TIME module is prone to loose its contents a few secon after the CL has been disconnected from a power source.

A standard HP-41 can keep the time for some 2'30" or 3 minutes just using its internal capacitor (470 uF).

Due to its internal design, CL's cannot hold charge enough in its caps to keep the TIME module running more than 15 or 20 seconds, which is a very tight gap if you need to replace a set of alkalines.

I'm not a SW guy, but like to have my clocks on time, so when it comes to fit a TIME module into my CL I included a small capacitor (220 uF 6.3v) PC CON type.

To avoid the capacitor being discharged thru the NEWT board, a diode is inserted in the module's power line.

As a result, the time is kept for about 1'45", good enough to replace batteries or find any other suitable power source.

Some pics my help with the details:

The TIME module disassembled and pre-wired.


The added capacitor.

And the TIME module in its new place.

Hope this can be useful for someone.

Merry Christmas!!

Diego


#3

Excellent job and your soldering skills are exquisite.

I will be hardwiring to my system also.

Cheers, Geoff


#4

Thanks for your kind words Geoff, same can be said on your restoration skills... :-)

Merry Christmas and all the best from the Canary Islands.

Diego.


Possibly Related Threads...
Thread Author Replies Views Last Post
  Reasonable price for a 41C, Quad Mem, Time, Navigation and Card reader module? Eelco Rouw 10 709 12-12-2013, 01:52 AM
Last Post: Eelco Rouw
  HP-41CL setup troubleshooting Xavier A. (Brazil) 2 310 12-02-2013, 06:29 AM
Last Post: Xavier A. (Brazil)
  [HP Prime]How to get Discrete-Time Fourier Transform uklo 0 272 11-18-2013, 08:02 PM
Last Post: uklo
  [41CL] New Extra Functions version Monte Dalrymple 0 181 11-08-2013, 04:32 PM
Last Post: Monte Dalrymple
  Rectangular to Polar, Polar to Rectangular – One more time Jeff O. 0 166 11-06-2013, 11:32 AM
Last Post: Jeff O.
  Date/time formats R. Pienne 4 353 11-01-2013, 12:43 PM
Last Post: Marcus von Cube, Germany
  How to set the Date.Time etc on a WP34S Harold A Climer 4 352 10-29-2013, 09:32 PM
Last Post: FORTIN Pascal
  Prime: Exam mode (possible duplicate after funny response first time) Paul Townsend (UK) 1 195 10-24-2013, 03:09 PM
Last Post: Tim Wessman
  Date/time programs for the HP 35s R. Pienne 0 160 10-03-2013, 02:37 PM
Last Post: R. Pienne
  So, latest 41CL / Library 4 config is... Gene Wright 4 341 09-22-2013, 02:59 AM
Last Post: Ángel Martin

Forum Jump: