help me run these led strips please!!!

[mattstolte]

Re: help me run these led strips please!!!

ok here are the pictures, the one is the 3 sets of red and black that are coming out from the power supply, then as you can see the way these leds are jumped there wired differently, then here is a pic of the 3 sets of wires coming to the boards. look at the connectors how can I run these to work

[budm]

Re: help me run these led strips please!!!

Need the pictures of the whole bottom side of the board, whole top side of the board, closed up the bottom side of the connector to be able to see the traces on that connector. It may be hard to take the pictures due to the fact that the boards are stacked on top of each other, but the setup looks familiar.
What is the model number of this TV?
BTW, try to hold the camera still.

[mattstolte]

Re: help me run these led strips please!!!

[budm]

Re: help me run these led strips please!!!

Hmm, the power supply board does not look like your board at all:
http://www.shopjimmy.com/apex-lk-pl3...upply-unit.htm

https://www.badcaps.net/forum/showth...180#post579180

[budm]

Re: help me run these led strips please!!!

OK, looking at the traces and the pinout of the connector, you are correct that the 3 stings (10 LEDs per string) are connected in parallel, so the total Vf is around 35~40 V range, the filter cap for the boost converter is rated at 100uF 100VDC.
The substituted LED strip has 8 LEDs per string (4 LED string connected in series to form 1 large string of 8 LEDs).
When one of the old string went bad (open circuit?) I would expect the other two strings to still light, but if the LED shorted out then all the LED string will be off since the VF will drop down.

[mattstolte]

Re: help me run these led strips please!!!

so how can I wire them to them led strips

[budm]

Re: help me run these led strips please!!!

So on the old broken strips connected, one at a time, does it light up and stay lit? I am trying to understand what kind of protection circuit it uses since the amount of the new LEDs is not the same as the old one.

[mattstolte]

Re: help me run these led strips please!!!

yes If I took the bad strip out the good one would work

[budm]

Re: help me run these led strips please!!!

yes If I took the bad strip out the good one would work

OK, that means the bad strip is shorted and caused the Vf to drop to below the VF for the good strips to run, but I expect the bad strip will to be on but but not all the LED on that bad strip will light up.
It seems to me that since you can run just two strips (same Vf but total current draw) without it going into protection shutdown, it may mean detect the Vf of the string, since the old one had 10 LEDS, the new one only has 8 LEDs per string so the circuit goes into shutdown.

[mattstolte]

Re: help me run these led strips please!!!

im thinking it is shutting down cause im putting a red and blck intoa connector that is either marked + or - did u see how the end of the connectoprs are labeled amd set up

[keeney123]

Re: help me run these led strips please!!!

BudM could matstolte put some diodes in series in the wire strings to compensate or maybe a mini-pot to adjust to the correct current?

[budm]

Re: help me run these led strips please!!!

im thinking it is shutting down cause im putting a red and blck intoa connector that is either marked + or - did u see how the end of the connectoprs are labeled amd set up

As long as the + (red) represent the Anode and the Black represent the Cathode then it should light up unless there is detection circuit that detects the total Vf of the string, if the total Vf is below then it know that there shorts on one or more of the LEDs, or wire is shorted to GND.
So to prove that theory you will need to use 7.5V 2~3W ZENER in series to make it think it has 10 LEDs instead of 8. the Zener will be connected in reverse polarity.

[keeney123]

Re: help me run these led strips please!!!

I'm thinking the 8 Leds are drawing more current. The the LED driver chip I had work on in the Westinghouse 26" TV. had a current sensor input in the chip and if the chip drew to much current then the circuit told the processor and the processor shut the LED driver chip down.

[mattstolte]

Re: help me run these led strips please!!!

budm where should i hook the diode up?

[budm]

Re: help me run these led strips please!!!

I'm thinking the 8 Leds are drawing more current. The the LED driver chip I had work on in the Westinghouse 26" TV. had a current sensor input in the chip and if the chip drew to much current then the circuit told the processor and the processor shut the LED driver chip down.

There should be a Power MOSFET that the Cathode of the LED strings will be connected to the Drain then the Source pin will be connected to the current sensing resistor, this junction point is then connected to the Feedback pin of the LED Driver IC to maintain the constant current through the LED string by PWM the Gate, so with less LED the circuit may not have enough range to turn on the MOSFET less to too much Voltage is developed on the sensing resistor which then activate the protection circuit.
He need to get the IC P/N to look up the spec.

[budm]

Re: help me run these led strips please!!!

budm where should i hook the diode up?

The Zener will be connected in series with the LED string, the + from the board will be connected to the Cathode of the Zener, then the Anode of the Zener will be connected to the + of the LED string which is the RED wire.

[keeney123]

Re: help me run these led strips please!!!

There should be a Power MOSFET that the Cathode of the LED strings will be connected to the Drain then the Source pin will be connected to the current sensing resistor, this junction point is then connected to the Feedback pin of the LED Driver IC to maintain the constant current through the LED string by PWM the Gate, so with less LED the circuit may not have enough range to turn on the MOSFET less to too much Voltage is developed on the sensing resistor which then activate the protection circuit.
He need to get the IC P/N to look up the spec.

Yes this is most likely true as it would think it is going into overload and shut it down before it fries something. If my memory serves me correctly, which I wouldn't rely on, I think the Westinghouse actually sensed the current on the return line to the chip. Whether is was by current going through the resistor or the voltage drop across the resistor I can not remember. Most likely there is and op amp connecter to a A to D converter that then feed backs to the processor. When the processor sees a High or low on that bit it makes it decision to either shut down or keep in on. This would be done on the first start up sequence and then the processor would monitor this pin as and interrupt.

[Ron.M]

Re: help me run these led strips please!!!

Dear People;...

It seems that some of you (mattstolte , for example) are wannebe Electronic Engineers !!!
The BEST way to solve this problem is to REPLACE the strips with the CORRECT ones...
This is done by looking ON EACH strip for a PART NUMBER & then searching for a supplier..
Need help with that , just ask !!!!...

My Vizio has 4 (FOUR) different types of strips that are NOT interchangeable...
Subbed , yes , easily remanufactured from recycled crap , HELL NO !!!
I predict more problems will erupt IF you continue along that road...
Trial & error experimentation as you are doing can cause bigger problems than what you started with...


But...
It's your TV....
It's your money...
It's YOUR CALL !!!


GOOD LUCK on your trip !!!!.....

Have a GREAT day & weekend...


Later...Ron.M...

[keeney123]

Re: help me run these led strips please!!!

You must understand that these LED strips were not available when I was troubleshooting the Westinghouse I had been given. They only became available recently. So want would you do throw the TV out or come up with a way to repair the problem?

[budm]

Re: help me run these led strips please!!!

You must understand that these LED strips were not available when I was troubleshooting the Westinghouse I had been given. They only became available recently. So want would you do throw the TV out or come up with a way to repair the problem?

BTW, the strip will be USED strip any way not brand new so the chance of failure will be just as bad, so is that the BEST way?