Help diagnosing UNI-T UT139C

[Ragnarokkr]

Hello,

I have an issue with my UT139C where I can't couple into the AC metering modes, pressing select only gives a bit higher pitch beep and as shown in the attached picture, the LCD goes all in.
Funny thing is that it only affects the AC modes, DC works fine as far as I am aware. Board and contacts have been cleaned with PRF6-68, original fuses are intact.

I'm totally at a loss, anyone able to help?

[Ragnarokkr]

Bump