The Icom 7400 / 749 comes with a large LCD, which has a well documented problem with the backlight. Basically, the transistor circuitry that powers the backlight is not up to the job. Eventually it fails. Whilst this display above looks clean and clear during the day, you can see nothing at night without the backlight. The transistor (Q302) in question is shown below from the circuit diagram.
This is usually blown because C302 and / or C303 dry up and cause extra current to flow through the transistor. There are kits on eBay offering similar components, which can then be swapped out. In my case, L301 had also gone open circuit. This was probably due to the high current flowing through it.
The old components were removed from the board using a hot air gun and some capstan tape and then the pads were cleaned, ready to accept the new components.
A quick test with my transistor tester, showed that the transistor was no longer a transistor but a diode. I had replacement caps on hand and a very similar transistor (BDX54C instead of the original 2SB1201) but in a slightly different package.
The transistor was mounted, with the corresponding mica shield, to the wall of the shielding and the SMD caps and choke replaced.
After powering the set up, the backlight was, once again, fully functional.
