Homemade LED tester for tv.

[capwizard]

Does anyone use their own homemade LED tester? The one can test whole LED screen and individual LED.

Can you share your experience?

except the one from shopjimmy. I love to make things myself, not to say that I have no money to buy but l love to do things myself.

DIY for fun. For led tester I only use the one I made.

[ducky29]

Re: Homemade LED tester for tv.

https://youtu.be/nZKjmljZqjs Check this. Id like to also add that 20$ for a led tester is a good deal, so you don't spend time and money on the homemade one.

[capwizard]

Re: Homemade LED tester for tv.

https://youtu.be/nZKjmljZqjs Check this. Id like to also add that 20$ for a led tester is a good deal, so you don't spend time and money on the homemade one.

Thank you. That is very smart idea.

But I try to built is a battery protable led tester or the tester could test led screen at the full current. Like an adjustable current and HV voltage power supply.

[CapLeaker]

Re: Homemade LED tester for tv.

I use a CV CC variable lab psu.

[capwizard]

Re: Homemade LED tester for tv.

But do you have a cc cv ps up to dc 400v.
An expensive power supply? Is it too heavy to handle?

[CapLeaker]

Re: Homemade LED tester for tv.

Why 400V? Don't need that. You verify that there is a problem with the LEDs, measuring the voltages on each string. Then you have to take it apart anyway, so I just test either the individual LED or a LED strip. My PSU can do up to 60V. Heck most of the time I don't need more than 30VDC. So why using a LED tester altogether? Useless, if you know the proper troubleshooting technique. Save yourself that money and buy something more useful than a LED tester.

[capwizard]

Re: Homemade LED tester for tv.

Why 400V? Don't need that. You verify that there is a problem with the LEDs, measuring the voltages on each string. Then you have to take it apart anyway, so I just test either the individual LED or a LED strip. My PSU can do up to 60V. Heck most of the time I don't need more than 30VDC. So why using a LED tester altogether? Useless, if you know the proper troubleshooting technique. Save yourself that money and buy something more useful than a LED tester.

For ex: samsung 40" up tvs. they will need 256 to 425v to test all the serial led strips at same time. LG tvs have 2 groups led strips will need to isolate the problems and give customers right estimates asap. At least should have 320v. (Ex shopjimmy's tester)

If I do not use good tester. I opened the screen then found out I am wrong that happened to me all the time.

I tried to achieve is the one better than the commercial one. With cc and cv Adjustable control and will cast you almost nothing.

My goal is to help people in Africa.

[CapLeaker]

Re: Homemade LED tester for tv.

Then you do something wrong. I mean once you press the power button the TV or monitor tries to start, check the voltages on each LED strip with your DMM and you should already know what is going on with the LED strings. That tells you o.k., do I have juice or nothing, why are the voltages off, what are the control voltages etc. and which way to go next. Never had a problem doing things like that. LED's are CC controlled. If something is going on, it will show up in the voltage.

[capwizard]

Re: Homemade LED tester for tv.

Then you do something wrong. I mean once you press the power button the TV or monitor tries to start, check the voltages on each LED strip with your DMM and you should already know what is going on with the LED strings. That tells you o.k., do I have juice or nothing, why are the voltages off, what are the control voltages etc. and which way to go next. Never had a problem doing things like that. LED's are CC controlled. If something is going on, it will show up in the voltage.

You are so smart, you are a genius.

That's the way I am doing. just use led tv power supply from tv and modify to a tester. In theory you can have as many led tester as you want.

All you need is a potentiometer and the few resistors. I have been used this kind of homemade tester for for 5 years.

[CapLeaker]

Re: Homemade LED tester for tv.

its just my way of dealing with it.

[capwizard]

Re: Homemade LED tester for tv.

its just my way of dealing with it.

If something is going on, it will show up in the voltage.
Every day electronic secret recipe must be remembered .


Can this be used on a multi-connector LED screen? I mean some tv has led backlight connector, Connected in parallel Up to 16 connectors. Will this work? or Just patiently test each connector?

Do I need a multi-meter with fast/peak min/max to catch the voltage?

[capwizard]

Re: Homemade LED tester for tv.

For ex: samsung 40" up tvs. they will need 256 to 425v to test all the serial led strips at same time. LG tvs have 2 groups led strips will need to isolate the problems and give customers right estimates asap. At least should have 320v. (Ex shopjimmy's tester)

If I do not use good tester. I opened the screen then found out I am wrong that happened to me all the time.

I tried to achieve is the one better than the commercial one. With cc and cv Adjustable control and will cast you almost nothing.

My goal is to help people in Africa.

This is the tester I've been used for years. Adusteable votage dc 2.6v to 526v. current sets to 10ma or 256ma.

The tester inside is a Samsung led tv power board modified with few resistors and potentiometer.

[CapLeaker]

Re: Homemade LED tester for tv.

so you converted it to CV? I mean you adjust the HV up and down, right?

[capwizard]

Re: Homemade LED tester for tv.

Yes sir
Just similar to TL431 I put a potentiometer to change the reference voltage. And then i have a variable, adjustable voltage power supply.

The green wires are connected to potentiometer. The other two white wires are for the output.

The other side of the power supply board. I changed 12 volt to 24 volt so I can use the T12 soldering iron. I connect a potentiometer to the tl431 after I found the value then I put a resistor over there. So LED screen tester and Power supply for solder iron.

Somehow the meter couldn't use the 5V inside the board so I have to use external 5V power supply. I put a USB charger to provide the 5v for the meter.

I set the high-voltage to 300v because more than that I begin to have a feeling to the high voltage.

Basically if you have any led tv power supply laying around. all you need is one resistor and one potentiometer then you have it.

Ps...The potentiometer I used is a 500K from light dimmer with switch.

[budm]

Re: Homemade LED tester for tv.

So it is CV supply, so how do you set/limit the LED current to be as specified?

[capwizard]

Re: Homemade LED tester for tv.

So it is CV supply, so how do you set/limit the LED current to be as specified?

it is one of original factory settings. current control was branch out, became very complicated.

it wont be too hard to convert current control to voltage control which i changed Rf2 to potentiometer and Rf2 to a resistor in the picture 1

[budm]

Re: Homemade LED tester for tv.

Dim control will vary the current through the LED or change the existing LED CC sensing circuit that the LED driver already has.
That feedback in your circuit is for sensing the output Voltage so the feedback is used for maintaining the Voltage so it is Voltage control. you need to sense the current flowing through the load to maintain constant current.

[capwizard]

Re: Homemade LED tester for tv.

i knew that but it is very hard to find out cc sense circuits with no circuit diagram. 289ma at 331v was factory setting. 10ma current i used LR8 high voltage regulator to accomplish the job. if it has cc would be wonderful.

[capwizard]

Re: Homemade LED tester for tv.

Dim control will vary the current through the LED

are both digital and analog dimming can change current of the PS.

for D-Dim how can i built a adjustable PWM?
for A-dim what is the voltage range?

[budm]

Re: Homemade LED tester for tv.

i knew that but it is very hard to find out cc sense circuits with no circuit diagram. 289ma at 331v was factory setting. 10ma current i used LR8 high voltage regulator to accomplish the job. if it has cc would be wonderful.

Up load pictures of the board. You can also look for the LED driver IC psec and application notes so you can modify the circuit.
BTW, how do you connect the LED to the power supply board, the Anode of the LED string to the Booted Voltage output pin and the Cathode to chassis GND? or L - return pin, that is important since the LED return circuit is not directly connected to GDN but through PWM Controlled MOSFET and current sensing resistor to maintain constant current through the LED's which your board is made for, low side (active element is on the return side of the circuit) constant current circuit.