Light meter is stuck and unresponsive to light changes

I got this Nikon D2H on eBay,

I wasn't expecting much, but it's in really good condition and everything works,

except for the Light Metering, I tried every option, reset, firmware update, settings, whatever. I shoot with D7100 so I am familiar with DSLRs. Simple settings and reset doesn't resolve the problem.

The issue is that the light meter doesn't change with the light in the scene, it doesn't change at all, it just stays at one point that it "thinks" that the metering is correct, so I can change the S or F or ISO to make a "correct exposure", but that exposure is just something that is stuck, has nothing to do with the subject or scene I am shooting.

I read online that this problem is a manufacturer malfunction, but the camera is old and Nikon won't even advise on which part to replace to fix this issue.

Can anyone advise?

Thanks