Help to repair an HP91

[isanchez]

Hi,
I have checked the 91 with an ACT from a working 97... And the problem is still there.
So, the act is not the problem. As I mentioned I have a 97 with a similar behaviour...and the problem was not in the main PCB ( I have switched the PCB with a working 97)....this means the problem is in the display control area/ board.
Is it feasible to find equivalent elements to replace the anode/ cathodes for the97/91? For the hp67 it is. Thanks for your help!
Kind regards