34401a 601 error repair

[f14]

Hi Guys
I have agilent 34401a with frontpanel damage. VFD display is broken and I buy a new one(clone ) from aliexpess.  after install new VFD . my 34401a have two beep ( the first one is quiter a bit) and VFD display is bright all segments and suck in this. all buttons is not respond
I remove the display board and connect the mainboard to PC via GPIB and this mainboard working correctly . (just have one error 601) all functions  are good
so I think display board  had damage too . I have check LM339M but it normal. seem the MCU 80C51 is dead ?
thank you!

[strawberry]

broken trace or solder

[f14]

I realize N80C51BH is dead. so I replace it by AT89S52  with fw found in here . after that display have this message "QTTR022" and when I perform self test it show like second picture
when I connect the display board with mainboard. I can not access controll via gpib . it freeze . have any idea for this issue ?
solved. this fw 88813 is too "new" for my 34401. 88804 working