Update:9100A with no display



#2

Still no display... I've verified the KB as OK. Probing on the core data board I found that D3 is not pulsing. All other Dn's are pulsing at the respective sense amp output transistor collectors (labeled D(n) on the schematic.) The inhibit FF's (F20 - F25) are all toggling except F25 which is D3's inhibit. K25 is toggling but J25 is not. J25 is the OR of BAddrE' and SC4 and a couple other signals. BAddrE' and SC4 are both toggling but at any given time one is a logic 1 so J25 is stuck at 1 (0V). And now I'm hoplessly lost... ;^P


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 8 460 10-10-2012, 10:05 PM
Last Post: Luiz C. Vieira (Brazil)
  9100A with no display now working! Richard Wilder 5 231 12-10-2011, 01:48 PM
Last Post: David Ramsey
  HP 9100A/B Transistors Richard Wilder 1 142 11-11-2011, 09:08 AM
Last Post: Joel Setton (France)
  Looking to borrow an HP 9100a/b for a technology gallery in NYC Keenen Thompson 0 93 10-26-2011, 04:45 PM
Last Post: Keenen Thompson
  Steve Jobs meets the 9100a Howard Owen 0 107 10-24-2011, 01:55 AM
Last Post: Howard Owen
  9100A with no display Richard Wilder 11 463 01-05-2011, 04:30 AM
Last Post: Tony Duell
  How to repair my HP 9100A calculator ? Jonathan 14 614 08-11-2010, 04:09 AM
Last Post: Tony Duell
  16 segment Led display would mimic a HP-41 display? Giuseppe Marullo 3 259 11-12-2009, 08:08 PM
Last Post: db (martinez, ca.)
  WOW talk about your retro calculator HP 9100A Donald Williams 8 343 10-15-2009, 08:16 PM
Last Post: Mark Edmonds
  eBay: HP 9100A Howard Owen 0 150 03-04-2007, 09:57 PM
Last Post: Howard Owen

Forum Jump: