Sony KVM1430A low contrast

[vol.2]

Originally Posted by bigboss80

I don't have an oscilloscope, nor a color bar generator, I use a DVBT with color palette as a generator, from what I understood by reading R812 it is part of the ABL (Automatic Brightness Limiter) circuit, but I don't know if I misunderstood the diagram

It's out of spec and should be replaced. It's not likely that being that much out would mess things up that much. It's 70% of value, and the typical tolerance is 80%-120%. So it's a little low, not a smoking gun.

Even if you don't have a scope, you can use your DMM to check all the power rails shown in the service manual to start. If you can verify those are good, you can start checking voltages around transistors associated with the circuits that might have an effect on the brightness.