HP42S battery failure



#2

For some time my 42S refused to operate more than a few seconds and checking with a ohmeter showed the battery terminals resistance around 38 ohms. I used the forum to find out how to open it (had to drill out the plastic pillars)and soon found the pcb mounted electro was the culprit. I think the value is around 100uF. replaced with two 68uF in parallel and it has now come to life.Also explains why the battery change over caused loss of memory.


Possibly Related Threads...
Thread Author Replies Views Last Post
  A prime failure Jan 17 2,338 12-06-2013, 08:02 PM
Last Post: Michael de Estrada
  IR printer failure Andrew Nikitin 7 1,075 11-05-2013, 11:25 AM
Last Post: Andrew Nikitin
  HP 2225D+ RAM failure/replacement Luca 4 850 09-10-2013, 01:46 PM
Last Post: Luca
  17bii failure db (martinez, ca.) 5 814 01-16-2013, 03:12 PM
Last Post: Jeff O.
  HP42S John Mosand 5 956 07-22-2012, 03:13 AM
Last Post: Les Koller
  HP42S graphics Han 2 606 07-20-2012, 12:23 AM
Last Post: Raymond Del Tondo
  HP42s ROM aurelio 18 2,932 06-26-2012, 09:36 AM
Last Post: Thomas Klemm
  aOT--Battery/battery contact care advice needed Matt Agajanian 0 445 04-24-2012, 07:35 PM
Last Post: Matt Agajanian
  x root y on hp42s David Griffith 14 1,556 04-08-2012, 12:43 PM
Last Post: Walter B
  Expected lifetime and failure modes of vintage 15C? Eric Zoob 30 2,711 03-22-2012, 12:02 PM
Last Post: Juan J

Forum Jump: