On a magnaox 37mf331d/37. the menu keeps scrolling. cant reset to factory. where to get a reasonable main board?

Fault with the main power supply regulator section. Either it will be on a separate board, or on the part of its main board. Check and replace damaged component/s at its main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts.
http://electronicshelponline.blogspot.com/

check the bulb inside LCD TV...

For magnavox/Philips model #37mf331d/37 part# is 313815864961.

There are two places to look for the problems, the backlight inverter board and the power supply. Look at the power supply first since it is easier to get to, look for burnt parts, bad capacitors, etc.
http://en.wikipedia.org/wiki/Capacitor_plague
Please post back what you find.

The problem can be in the backlight inverter board (hard to get to), or the main power supply module may not be working. Look at the power supply first since it is easy to get to, look for burnt parts, bad capacitors.
http://en.wikipedia.org/wiki/Capacitor_plague
Please

The main board has become faulty. The logic in the TV is bad that is causing the TV to have such problems. The only way to fix is to replace the main board.

Your set either has a bad SSB (small signal board) or needs a software upgrade. Try the upgrade first by going to http://www.m4c.magnavox.com/cgi-bin/dcbint/cpindex.pl?scy=US&slg=AEN&cat=FLAT_TV_CA&sct=LCD_LARGE_30_40_SU&grp=TV_GR&session=20090830171041_4.131.87.247&ctn=37MF331D/37&mid=Link_Software&hlt=Link_Software
Download the latest software release for your set then follow install instructions that are contained in the user manual for your set.

Disconnect the LVDS Cable that runs from the small signal board to the display panel and apply power,if the screen comes on,the Small signal board (aka Scaler Bd ) is the faulty board. other than that,all that's really left that has gone bad for me is the logic board.

To do a reset, go to your main menu and select 'Settings'. Select 'General' from the list and scroll to 'Master Reset' and select. Select 'Reset Settings'. If the phone prompts for a password, enter the default 0000, unless you've changed the phone's password.

To do a master reset, go to your Menu, then select Settings. Under the General tab, scroll down to Master reset and press select. Select Reset All and press yes.
If prompted, the default passcode is 0000.
Please note that a Master Reset will return the phone to its factory default settings. All user data and settings will be deleted. If you have any files or information you would like to save, you should either back it up to a memory stick or your computer. Your contacts can be backed up to the memory stick or your SIM card.

Your set is in DEMO mode......consult owners manual....
Usually in menu pages.........Oh, switch back to English...
select Lingua to change.........T.