Mulja tv repair portal

Equipment Repairs => LCD TV forum => Topic started by: ocf on August 02, 2016,17:38:01

Title: Samsung - LE46C750R2K - BN44-00341A PSU - No Power
Post by: ocf on August 02, 2016,17:38:01

I have a 46" that wont turn on, standby light flashes four times slowly then one time fast then repeats. No clicking or noises from back of TV.

All caps look good and voltages look good. When Mainboard is disconnected from PSU and power button is pressed the backlight comes on. Another forum post suggested this shows it is a mainboard issue.

I found a burnt 5w resistor on psu and a few of the mosfet leads around this resistor look dry, I will resolder tomorrow and find a replacement for the resistor which is reading at 5 ohms.

Do you guys have any past experience with this model of TV or PSU

Title: Re: Samsung - LE46C750R2K - BN44-00341A PSU - No Power
Post by: downunder on August 03, 2016,04:02:19

Hi ocf,

Becoming quite a regular here. Correct re the main board.

Title: Re: Samsung - LE46C750R2K - BN44-00341A PSU - No Power
Post by: ocf on August 03, 2016,05:42:21

Hi Down Under,

I think I will be here for a while :) Are you the only active one here :P

So if its the mainboard do we have any idea where the failure is, I have a hot air rework station so able to do small chip reflows etc.

If I want to go about replacing the mainboard how do I do that, same mode number etc, what about eeprom? does that have to be swapped over to the new board?


How sure are we that its the mainboard, still don't like the look of a resistor I found, it's marked 5WR05K I'm assuming 5w 5k ohm resistor, does that sound right? I cant find a datasheet referencing it directly. This resistor is located near the bridge rectifier and transformer.

Thanks for the schematic but it doesn't seem right, the resistor I'm seeing as dodgy is RP821 and that is showing up as something completely different on your schematic, does the A/B revision make a big difference to the physical board?