On GARULFO, and I suspect on other A54s and maybe SM, there are three 24VDC to 12VDC converters, marked “permanent”, “hydra/iscan v90” and “VHF icom”.
Of those, only the “permanent” one has the input +0V and the output +0V posts connected.
Does anyone know why that is?
Why shouldn’t the other 2 be the same?
In one pic: