Brymen BM257 probe jack faults

[glatocha]

Hi,

I am asking you guys for any help to bring back to life my BM257. It served me well for over 10 years on both industrial and hobby usage.

The problem is that is shows InEr on all settings except mAuA. I am suspecting that something is wrong with the leads detection. Normally this error is shown when I try to measure V/Ohms and the lead is plugged in one of the Amps inputs.
So I am guessing something is wrong with the lead detection. It thinks the probe is still in mA when it is not? How does it work? what can I check to resolve the issue?

Many thanks for any help
Greg

linking Dave video with quick review: