NF ZM2354 LCR meter ERR77?

[mrf245]

I got a NF model ZM2354 LCR.
It worked fine until last time I turned on it, It didn't execute normal boot sequence,but displayed "IL ERR 77".
I asked another friend who have some ZM2354, he sadly told me that all of his 2354 also have the same problem----IL ERR 77
Most ERR 77 happened after normal use several times. I check manual it only shows ERR77 is "hardware problem". What hardware problem?
Anyone know how to solve this problem? Thank you very much...
 

[coromonadalix]

Seems your lcr had some beating on the top panel case could not find a complete manual ...

Does it have some battery inside ?

Maybe some loose part, connector, socketed chip, or even bad/cold solder ?