Mark - Keysight MAY have that spare VFD still in stock (German office supposedly had a few). Several HP-34401A DVM owners have used that Chinese source for replacement. The display model being sold appears to be: SAMSUNG SSVD INB-12MM52T Good luck ! greg > I looked closely at the display and can see unused annunciators for frequency, us, period, etc. > So the display is the same as used in at least one of their frequency counters. > The display is a 12 character 14-segment display. > There is a possibility that a HP-34401A display might work. > Those are available from China for around $50. > - Mark Sent from iPad Air

Internet Fishing expedition, produced some cross-references :-) Keysight 34401 DVM --> Service Guide, page 133. http://www.keysight.com/upload/cmc_upload/All/34401-90013-mla2.pdf 34401-66512 – Display Assembly (A2) Vacuum Florescent Display (VFD) was OEM CP3033A (Noritake part). Noritake VFD Basics https://www.noritake-elec.com/technology/general-technical-information/vfd-operation Some EEVBlog readers attempt VFD rejuvenation https://www.eevblog.com/forum/chat/vacuum-fluorescent-display-rejuvenation/ greg Sent from iPad Air > On May 9, 2017, at 10:46 PM, Gregory Beat <w9gb@icloud.com> wrote: > > SAMSUNG SSVD INB-12MM52T