How to replace lamp ballast 46hm84
Assuming you can get the part, here is the procedure to replace the lamp ballast:
1. Make sure TV is un-plugged and the lamp has cooled for at least one hour before continuing.
2. Place the TV on a flat surface with sufficient space to the rear to allow you to slide out the chassis.
3. Open and remove the lamp access door on the left-side of the TV (facing the front) by loosening the thumb screw. Behind the door you will find the lamp assembly which must be removed by loosening two screws (one on either side of the lamp base). Pull out lamp unit, careful not to touch the lamp or bump the unit. Set aside.
4. There are 13 screws that hold the lower-rear cover onto the cabinet. Use a 1/4 inch nut driver to remove these screws. Nine of them are along the top and bottom at the rear and another 4 on the left and right hand ends of the cabinet just to the rear of the front panel.
5. Next, note that the chassis is in two sections; left and right. The lamp ballast is part of the light engine assembly that is on the right chassis. You will save yourself much grief if you slide out both left and right chassis assemblies. There are 4 screws through the jack panel that hold the left-side chassis to the cabinet. Remove these screws. Also, there are two screws mounted vertically (one on either side) of the jack panel that hold the left-side chassis to the bottom of the cabinet. Remove these screws as well. Note that they are different from the other screws.
6. The right side of the chassis is held by 5 screws. First, remove the three screws that are holding the verticle metal brace and remove the brace. Note that there is a cable tie connected to this brace. Be careful not to cut or exert too much pressure on this cable tie or the cable running through it. Next, remove the remaining metal screws holding the right chassis.
7. At the top of the open cabinet just behind the metal brace that has need removed, you will see another metal screw that holds a light shield in place. This shield has several small wires that run through guides. Carefully remove these small wires from the guides remove the screw and gently remove the shield taking note how the shield is supported so you can re-install it again easily.
8. At the left side of the jack panel towards the front of the cabinet, you will notice some wire guides with wires routed through them. Carefully remove these wires from the guides so you can pull out the chassis without putting strain on the wires.
9. CAREFULLY, start to slide out both chassis sections, left and right. Be careful not to pull any wires. If you notice a wire that is becoming tight, stop and make sure you take the strain of off the wire before continuing. You will most likely not be able to fully remove both chassis. You will not have to in order to replace the ballast.
10. The ballast assembly is located in the right-rear portion of the light engine assembly. It is held on to the circuit board by four plastic posts and retaining clips, one on each corner. The projection lens is part of the light engine assembly and is exposed. DO NOT TOUCH the lens with your fingers or tools. Before you remove the ballast, you must remove a metal piece that covers the heat sink. There is one screw on each side of this cover. The one on the left is difficult to reach with your fingers so use a magnetic screwdriver if you have one. If not, use some kind of sticky substance on the point of the screw driver so the screw will lift up with it. Remove the metal cover. Next, remove the two screws that hold the brown lamp socket to it's base and carefully remove the lamp socket. Also, there is a small white cable connector on the right-rear section of the ballast that needs to be CAREFULLY removed. Do not pull by the wires; use a needle-nosed pliers to grasp the plug and gently wiggle if off the connector. Gently move the white plastic clips at each corner and lift off the ballast assembly.
11. When installing the replacement ballast, be careful to gently seat the ballast by exerting pressure only on the four corners where the posts are. In this way you won't crack the circuit board. Replace that small cable connector, the lamp socket (it's key-wayed so it cannot be installed wrong), and the metal cover over the heat sink.
12. Take you time and follow your steps in reverse order. The both sides of the chassis must be slid into the cabinet together to avoid too much tension on small wires. Notice that there is a verticle tab on the light engine chassis that must be aligned on the right side of a veticle guide that comes down from the top of the cabinet enclosure. If you do not have the tab on the right side, the chassis will not fully seat back into the cabinet. Replace the light shield, route the small wires through the guides and also those on the left side of the jack panel, replace all screws and braces.
13. Replace the lamp assembly and replace the lamp door and hand-tighten the thumb screw. The set should fire up. If it does not, the problem may be with the light engine in which case it will not be worth the expense to fix.
Good luck and take your time.
Jun 08, 2009 |
Toshiba Televison & Video