Hello, Use the old light bulb test first to limit blown fuses. That is an incandescent bulb in SERIES with the ac line IN. It will glow brightly if the fuse is replaced and the short still exists. When cured it will glow dimly. This limits further overload damage and its cheaper that a case of fuses. HI It's going to depend on what follows that fuse. If a semiconductor, it's shorted. If an electrolytic, it's shorted. Use an ohm meter on rx1 and probe around to ground with POWER OFF and UNPLUGGED! Let us know what you see. My money is on an electrolytic or shorted regulator pass transistor. You can email me off line if you wish. I will be glad to help!
ARS W2DRH David R. Henry, LME Licensed Master Electrician Electronics Tech. ARRL Instructor
