HP-97 Display flickering


Good morning from Switzerland ;-)

Just received a HP-97 this morning and after some resoldering it seems to work.

One question though:

Is the noticeable display flickering normal?
Especially the flickering is heavier in the left hand digits.

Or something to do we have here 50Hz instead of 60Hz?


Do you have a good battery? The battery is required to regulate the supply voltage.


Pretty dead battery pack ;-)

But thanks for pointing me in the right direction...

Added a small 100uF capacitor across the 5V power supply, close to the AC input where it says "+" and "-" on the PCB...now the flickering has gone and also the printer motor moves...though one gear is worn out...


Well....voltage is a little too high now with the capacitor....

Gonna use a standard 5V USB power adapter now to be on the safe side ;-)


Replacement battery packs are available online on a well known auction site.

Possibly Related Threads...
Thread Author Replies Views Last Post
  Can the display for a HP32Sii be replaced with the display from another model? Bruce Larrabee 8 2,141 10-10-2012, 10:05 PM
Last Post: Luiz C. Vieira (Brazil)
  HP 67, 97, 97+ emulator Olivier De Smet 8 1,977 11-11-2011, 09:57 AM
Last Post: Israel Otero
  16 segment Led display would mimic a HP-41 display? Giuseppe Marullo 3 1,211 11-12-2009, 08:08 PM
Last Post: db (martinez, ca.)
  HP-97 Flashing Display Nick Taylor 5 1,178 12-21-2007, 04:56 PM
Last Post: Randy
  HP-97 Display Mode jyl 3 870 06-02-2006, 08:37 PM
Last Post: Thomas Okken
  HP-97 display question Mark Monica 2 751 08-08-2003, 04:11 PM
Last Post: David Smith
  HP 67/97 "Trick" Cards Warning for HP-97 Users Dan M (Vermont, USA) 0 597 09-12-2002, 08:31 AM
Last Post: Dan M (Vermont, USA)
  HP-97 Decimal Point Display Paul Nelson 17 2,716 01-06-2002, 10:46 PM
Last Post: paul nelson
  Can I use a HP 12C display as a replacement for a broken HP 15C display? Heather Hansson 2 898 05-01-2001, 10:44 PM
Last Post: Andrés C. Rodríguez (Argentina)

Forum Jump: