40''polaroid lcd(4011TLXB) has power to it but no pcture or sound? whats difference from power supply board and main control board

I would first check the power supply. Check the main fuse, if is blown and there was no power surge from an external source, the supply board has some serious problem. If the fuse is fine measure the output voltage of the power supply board. Check for any swollen electrolytic capacitors, they are the number one cause of every LCD failure I have come across. I just fixed a Polaroid FLM1514 which has a 2956C Ver 2.0 power board driven by a Fairchild CM0765. Turns out the VCC capacitor was bad and not even swollen, sowpped it for a 47uF 50V and presto.

I also had blown capacitors on my power supply. You can see when they're bad: the tops split or bubble up like a dome. I changed most of the caps, just to be sure, and it fixed the problem. Careful of the larger capacitors. They stay powered for some time and can shock you pretty badly. Good Luck

It sounds like the Main board (sound, video signals are from this board) is bad but the power supply and backlights are working.
Service manual: http://www.polaroidsupport.com

Basic LCD monitor and TV troubleshooting guide:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide
http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting
http://www.fixya.com/support/r7406380-tv_training_manuals
Failed TV and Monitors pictures: http://s807.photobucket.com/albums/yy352/budm
Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague
Parts: www.shopjimmy.com
Parts: www.interliquidparts.com
Capacitors kit: http://lcdalternatives.auctivacommerce.com/Default.aspx he can make you a set of caps.
Or www.digikey.com, just make sure to use caps with low ESR, 105c, high ripple current and long life rating such as PANASONIC FM or FC series.

Hi Scott,
Replacing the power supply board is not quite technical, no soldering required. But before an attempt to do so, let stand the unit for 1 hour to drain the main filter electrolytic capacitor. Power supply board is where the power cord directly connected. Pull-out all the cables connected from the existing power supply board and then put in the new board, re-insert the connectors and ensure that it is properly seat-in.
Click this link for the replacement or obtain it from your local Polaroid Service Centers.
Hope I helped you.
Thanks for using Fixya.
Jdvillanueva

Ur tv power supply board is defective.That the board where the a/c power cord go into it.Replaced the power supply board,ur tv will have stable power and work again.Tries websites like Shopjimmy.com,Ebay.com to buy a refurbish power supply board for the replacement.

If you do not get ANY indicator light , then you need to look at the power supply for the 5vdc standby voltage first whic will be in the power supply module, this 5vdc is needed by the main board to turn on the rest of the circuit. If you do have even one light, the n the problem can be in the controller board not sending the signal to turn on the main power supply section. Look at the power supply first since it is one of the part that fails most, next to the backlight board.
http://en.wikipedia.org/wiki/Capacitor_plague

Do you have any power supply boards left for a TDA03211C?

Almost anything could be an issue. The best advice is to take it into a service center to have it looked at.

I have fixed many polaroids, the problems is most of the parts are contained in one self contained control box. it sounds like your power board is not funtioning. contact polaroid and let them know about your problem and see if you can get a new control panel. the contol panel only has one connection and 3 screws to replace. hope this helps.

take the back off and look on PCB you should see a couple of 1000 uf caps bulged up and change them out.