AnsweredAssumed Answered

CAL coefficient in HP 8753B Ver 3.0 where are they located ?

Question asked by ON1EV on Sep 13, 2015
Latest reply on Sep 14, 2015 by theamberco
Hi ,all the community , I have an old HP 8753B Ver. 3.0 with the option 006, suddenly all the Cal coefficients have disappear from the menu CAL , i.e.  the C0 , C1, C2, C3 fringing capacitance coefficient have  changed to zero; the display show  zero in all cases. all the CAL kit inside the VNA have the same issue, the question is: Where are the Cal coefficient for each Cal kit memorized?  *inside the firmware or inside the EEPROM*? 

After this issue, my old HP8753B have refused to work, all my front panel LED are ON(see the picture)  and the HP LOGO and firmware are displayed(see the picture) and the VNA is stuck at this point. each time I press a key , an error message is displayed : caution invalid  KEY(see the picture).

I have suspected the A1/A2 front panel digital control, the ribbon cable is Ok. The VNA refuse to operate with the HPIB control, e.g. CAL KIT Manager program  refuse to control the VNA.
I also search an old A9 CPU board with the part N° 08753-60067.
Any help will be great and greatly appreciated.