How To Test LCD/LED TV Power Supply Boards(No Power)

Learn how to test LCD/LED TV power supply boards before buying a replacement. The TV power supply board under test in this video is from a Coby 32" LCD TV. Testing boards from other manufacturers or LED TV's should be very similar. Once the power supply board has been removed from the TV with the power cord still attached, the next step is to turn on the power supply by shorting 2 pins together(Power On) on the power supply board. Coby models use the designation, "PSON/5vSB". Other brands may differ(such as STB5V). Refer to the video for more details, and make sure none of the Electrolytic Capacitors are LEAKING or BULGING. If they are, replace them.

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Thank You!

[jameswiz]

WOW!!! I remember back to the days when I didn't own the proper sized test leads, and used stuff like Nails, Safety Pins, Paper clips and Chip Clips to make my own... One time, I needed an extremely precise set of test probes, so I silver soldered sewing needles to my spare set of probes. I still have (and use) that set

[vjohnny]

Thanks for the tip about checking backside of the board for voltages. Subscribed!

[brwnyes]

I actually found this video informative. I am into electronics and work with it day after day almost 7 days a week. I am opening to learning new things.

[shvideo]

Excellent content. Very well explained. I really wanted to know how to bypass the control board and be able to turn on the power supply through the input connector. Thank you very much for sharing your knowledge.

[UpcycleElectronics]

Hey FYI,
I've been trying to rig up a curb side special Vizio 42" as a bench light. I have the advantage of a working TV and am just trying to get the CCFL inverter working without the main board or LCD driver. This one has a 5 volt standby, 12 volt, and 24 volt rail. The PSU has an on/off pin, PSON, and PDIM pin. The inverter IC is one of the pesky o2 micro chips with an NDA Datasheet (OZ9976).
I can confirm, this power supply needs the PSON and ON/Off pin jumped to 5v. The PDIM pin needs to be set between 2 and 3.6 volts but does not need a PWM input.
However, contrary to your video here. The power supply will not start by jumping out the standby rail. It has to have a substantial load on the output for the main output rails to work. When I disconnect the 3 extra pins from the processor board and jump them out (on/off, PSON, w/a 3v3 regulator output on PDIM) but keep the connection for 5v, 12v, 24v, and ground to the processor, everything works like it should and the backlight comes on and stays on until I disconnect the mains plug.
I am here because I have been looking for ideas on how to rig something as a load. I've tried load resistors all the way down to 270R on the output and that doesn't work. I don't want to go much lower on a 24v rail. I'm about ready to just add an auxiliary supply for the inverter IC or use a small boost circuit from the 5v rail. I thought you might have covered something like this here, but after seeing a discrepancy between what I'm seeing and the video I thought I'd mention it. This TV is probably some rare exception, but I figured it was still worth mentioning that jumping the on/off PSON pins doesn't get power going on this design.
Thanks, -Jake

[jdl]

Excellent job on this view. It helped me troubleshoot a 50 inch TV and change out the board for 35 bucks!

[johnantopinq]

Thank You Sir, I have here a power supply of LCD TV but I dont know how to use the power supply but since I saw your vedio, I try it and it works, Now I have power Supply, 24vdc, 12vdc, 5vdc . I can use this one now for making small watts amplifiers .

[sandowne]

Great work here....not exactly sure what was wrong...but after following your instructions...all is ok now!! Thanks

[EnriqueRodriguez-ufbo]

Thank you for making this video. Between this information and the troubleshooting flowcharts in the Sanyo Service Manual, I was able to fix my Sanyo FVM4012 TV by replacing the power supply board.

For future reference, my symptoms were:
-RED power LED on whenever AC cord was plugged in
-No backlights, no image, no sound
-3.3V Standby was present on both the Power Board and Main Board
-No 24V present on the Power or Main Boards
-No 58V on Power Board

I don't know which component(s) failed, I just replaced the entire board.

[ruby-mangalath]

Than k you sir, now I know how to use a old tv power supply for other purposes .

[brig.]

good tutorial...I've been taking power supplies out of old disc players etc. that people throw away I usually connent blubs to them and then measure the voltages.

[Drunkmanatee]

Thank you for the excellent explanation!

[randallbaker]

Thanks for your video. I can't seem to find a 'SB' or 'STB' pin. The other two pins are labeled 5V and DIM (O/F) not counting the 12V and GND pins. When I touch the black probe to the ground and check the 12V pins they all show 12V. I guess my board is defective.

[paulmorrison]

As usual many thanks for sharing - wasn't sure about power/on pins and you more than clarified that for me.

[danbob]

Hi there using your method I have checked Apple LED Cinema Display power supply board on all the pins reads close to what it says (only like 0.2 or 0.4 V difference) apart from one pin where it says 24 V and reads 25, 2V is that acceptable?(using mid range multimeter)

[prestonrenify]

Your microwave troubleshooting video and this one has inspired me to tackle troubleshooting and possible repair of my 2 year old 60 inch Samsung LED TV. Was working perfectly, then image quality began to deteriorate, then one day got odor of MS (maximum smoke) from rear of set. There seems to be an extremely dim image present. I'd love to return this unit to service. Can use it downstairs. Do my symptoms seem consistent with a possible PS problem?

[northc]

Got power to all pins. 24 v pins I only have 21v. Tv turns on but screen is black. Amy suggestions?

[peterishikawa]

I have back massagers that won't turn on. I have a lot of them but can I mail you a couple of them to you to see if you can find the problem and post it on youtube? I will ship it out free and you can keep them after it's repaired.

[ainsworthlynch]

I have no problem Identifying the power pin I just don't know what to bridge it with to power on the board I have (2) 3v pins along with some 12v and 24v and gnd's, that's why I told you the TV in case you could check the board and see which other pin I should connect the power pin to

[victorokenyi]

My Finllux 50F6090 video keeps going off while the audio is still on. You can change the channel and get the audio for the channel but without the video. Looks like it is the power that is being lost. If one turns off the TV the video comes back perfectly but is soon lost again This cycle is then repeated again and again. What could be causing this intermittent black out of video in this set? Help please