Hitachi 43fdx15b power light stays on all the time

When u turn the tv on,u hear alot of clicking?That mean the Ballast that help the projection bulb to work is dead.Change the Ballast,might as well change the bulb too.U don't know what is the condition of the projection bulb in.

3 reasons for this.

1st reason the fluid is contaminated and thats why u dont get red.

2nd reason no red drive possibly due to a bad colour driver on the base of the tube neck.

3rd reason the tube is out.

that might just be a standby light. normal, if its working ok don't mess with it

Just a thought, but check all of the pico fuses for a blown fuse. The pico fuses look like a small yellow resistor. Some Hitachi's are famous for having a blown hi-volt ceramic capacitor and a blown pico fuse.
I think the red led on is a short protect indicator, but I could be mistaken.

This can be caused by a few things. The red crt/picture tube is going bad, which it would have to be replaced, tube can cost anywhere around $195 and up, if it is available. Another problem can be a bad transistor or IC on the red crt circuit board. Either way it should be taken to a repair shop. The average cost for repair could be over $300.

Symptom: DARK PICTURE OR MISSING COLOR
Cause: CLEAN SPARK GAPS, CRT PINS AND SOCKET ON CRT PWB

You can try replacing the convergence IC's ...should cost you about 350-400$..Its your choice at the end of the day,,It could also be that the lamp is blown and you will need it to be replaced. Best option..call a tech and get a quote and then decide..

u lost hi volts. bulb most likely

Sounds like you may have a sticking Relay S901 on the power board. Tapping the Relay may Make The Light Go On And Off. The relay part number is FJ00142 if you can find someone to work on the set for you as it would involve soldering in the new part. The number on the relay may be ALKS329 with the former part number being the Hitachi Part number.

common fault on hitachi is the -26 volt supply is bad,ther should be voltage markings near or around the led's,find the b+ one thats missing or being pulled down