20 Most Recent Samsung LN40A650A LCD TV Questions & Answers

Fault at its main digital board. Short circuited component/s at it. Contact any service technician; or the authorized service center. If you wish to get some details; check the site linked here. Pull up older posts. http://electronicshelponline.blogspot.com/ In most cases, the main board might have to be replaced. If so, a software [firmware] update too might be necessary. .

check you main board

Firmaware upgrade guide and file: http://www.samsung.com/us/support/downloads/LN40A550P3F

does it go away when the set warms up? or if you tap the set? Sounds like a possible defective LCD panel tab. Samsungs and Sony's are known for this.

Try adjusting your Convergence settings.
http://origin2.samsung.com/us/consumer/tv-video/televisions/lcd-tv/LN40A650A1FXZA/index.idx?pagetype=prd_detail&tab=support
http://www.retrevo.com/support/Samsung-LN-40A650-TVs-manual/id/16697dj790/t/2/

user guide manual above.
You will need to enter the service mode usually by press a combination of remote buttons.
When entering the service menu do not change any settings except the ones intended.
Basically this is the process as I remember
With the TV off, press mute 1 8 2 power .
The TV will come on with alot of sub menus listed
you can enter a sub menu by selecting it using the enter or right arrow ?
The up down arrows (on the remote) are used to navigate up and down the menu and also for adjusting when in a submenu
You are looking for the words "Shop Mode" its located in a submenu called options.
When you find the "shop mode" item, adjust it to OFF.
If it is found to be in the ON position, the TV doesn't retain settings, so simply make sure its in the OFF selection
Try this if you want.
Do not adjust anything except the shop mode setting to OFF

Just fixed my Samsung LN40 check fan #1.Unplug, Take the back off (like 20 screws were hard to find them all) fan is exposed in the middle. Unscrew fan, used q-tips and nozzle tool on vacuum cleaner to remove built up dust gunk. Blew in center of fan to dislodge dust. Screwed fan back on, plugged in to see if fan was spinning to cool TV. It was and the check fan message disappeared. Put the back on. Feeling Lucky no big repair.

You have to check whether the back-light inverter gets its proper voltages to function. There as many voltages that controls the back-light inverter. Check these is a skilled work. Contact any experienced service technician. If you are not familiar with electronics, do not attempt to repair. Whether you suffer fatal electrical shock! Instead, contact the nearest service center.

remove back cover and clean fan with q tip and alcohol also vacuum all around do not use compressed air to blow on it

Replace the main bd. Have a trained Samsung tech troubleshoot to confirm.

Check and replace the T'Con board. It is faulty.