I need to replace the small IR board in my Viewsonic N3742W LCD TV. I have the board and have taken out all the screws ion the back panel. I just don't seem to be able to separate the cases to get at the IR board.

Download the service manual from here:
http://elektrotanya.com/viewsonic_vt2430-1m_vs12335-1m.pdf/download.html

Ur tv the LCD inverter board is dead.Replaced the LCD inverter board u will get ur picture back.Tries websites like Shopjimmy.com,Ebay.com to buy an refurbish LCD inverter board for the replacement.It a long board in shape.

The button board or the IR board in the TV. A stuck button can cause some strange behavior. Typically, the TV has 3 control lines: POWER BUTTON, FUNCTION BUTTONS, IR (Remote). Try disconnecting the button board, it should have a connector right on the board. If that fixes it, you can leave it that way or try to find a replacement board (not sure where you should look). If it's the IR board and the button board is daisy-chained through it, you will need to either replace it or repair it. Most often the little receiver is bad when there is a problem with this type of board. You may be able to find a Receiver IC, but just know that it has to match the TV. I hope this was helpful and points you toward your destination. Best wishes.

Ur LCD inverter board is dead.This board help to get the backlight to the LCD screen to make the Tuner board get the tv signal throught.Replaced this LCD inverter board will get ur picture back.Tries websites like Shopjimmy.com,Ebay.com to buy a refurbish LCD inverter board for the replacement.It a long board in shape.

here the ebay power supply for you TV
http://cgi.ebay.com/Viewsonic-N3020W-30-LCD-TV-Parts-Power-Supply-Board-/400152574059?pt=LH_DefaultDomain_0&hash=item5d2af3b86b

IR senor may not be bad. Try using a different remote (universal) and program to TV. If universal remote works and your doesn't, you may need to purchase a remote instead of IR board. If you confirmed that the IR board is bad then replacing the IR board will fix the remote issue. IR board is an easy fix. Just open the back cover out and it's located right in the middle toward the bottom of the TV.

what you have is a bad IR sensor board. The part # is:
313926859182. Right now, there are so many of these things failing, that finding the original might be difficult.

Don't fear, though; it's a small part. And, best of all, it's cheap. Expect to pay around $5.00 for the part, maybe a bit more, maybe less, depending on the supplier.

Now, if you are handy with a power drill (fitted with an octagon/star bit for the back of your set), you can remove the 20 or so star-bit screws from the back of your television. Don't worry about putting the set on the floor. If your TV is on a stand, simply turn it around. You'll need to remove the stand screws, but you won't need to take the TV off of the stand.

Now that you've taken the screws out and removed the back cover, look in the lower left hand area of your set. You'll see a 4 inch long circuit board with 2 cables running to it. Pull the cables out (they'll come out easy). Remove the 2 star-bit screws.

One of the board's sides is under a plastic tab. Lift the board out of its slot from the other side.

Put your new board in, reconnect the two cables, reassemble the back and you are set to go.

Expensive repair for a few bucks and a better IR sensor.

This appears to be common, with them stopping working, check or have someone check the power board. The TV will need to be taken apart. I had something like this happen recently...was working one day and not the next, turns out to be bad Capacitors on the power board.

Check the power board, capacitors seem to be possibly faulty on this model. TV will need to be taken apart.