(DPS-168JP A) Power Supply / LED Board LC-60LE600U

[djpat1974]

Hi I have and (DPS-168JP A) Power Supply / LED Board LC-60LE600U with no backlights I just need two resistors r7204/r7203 what size are they mine blow up and cannot be read I try so many different resistors and all they catch on fire please see the picture I have circle them thanks

[R_J]

Re: (DPS-168JP A) Power Supply / LED Board LC-60LE600U

They seem to be marked 100kΩ but are likely 100Ω

[djpat1974]

Re: (DPS-168JP A) Power Supply / LED Board LC-60LE600U

hi thanks for your reply i tried that and they would burn out 100 ohms and 100 k

[R_J]

Re: (DPS-168JP A) Power Supply / LED Board LC-60LE600U

Check that you don't have shorted diodes, if they are ok, you could have shorted led's in the panel, there seem to be 4 seperate led strings I suspect you have a problem with 2 of them, line 3 & 4

[djpat1974]

Re: (DPS-168JP A) Power Supply / LED Board LC-60LE600U

thanks again the back leds lamps are brand new I change them I could get the tv to come on with 660 ohms resistors but they burn out in about 1 min it could be like you say the diodes

[R_J]

Re: (DPS-168JP A) Power Supply / LED Board LC-60LE600U

Did you change all the backlights or just the two strings? or did you just change the led's on the strips? I don't think your problem is on the power supply board

[djpat1974]

Re: (DPS-168JP A) Power Supply / LED Board LC-60LE600U

I change leds strip all of them

[R_J]

Re: (DPS-168JP A) Power Supply / LED Board LC-60LE600U

T7601 transformer drives the 4 led strings, The positive of all 4 strings are connected together, the negative of all 4 strings are connected together AFTER each resistor, R7203, 7204,7205 & 7206. If there was a fault on the power supply, all 4 resistors should burn up.
That only leaves the led strings themselves, They can't be the correct strings
Also R7206 & 7205 are 68Ω , R7204 & R7203 are 100Ω, that would indicate to me the two sets of led strings are different.
led1 & led2 are not the same as led3 & led4
I checked a video and I can see each strip has 4 wires, I suspect there are more leds on one side of the strip than the other and led1 and led3 connect to one strip and led2 and led4 connect to the other strip.

Is this what the plug looks like going to to the leds in the panel? do you have 8 wires?

[budm]

Re: (DPS-168JP A) Power Supply / LED Board LC-60LE600U

Each one of the resistor is connected in parallel with the Upper LED power supply filter cap.
If you look at the bottom side of the board you will see that
R7203 in parallel with C7204 22uf 200V
R7204 in parallel with C7205 22uf 200V
R7205 in parallel with C7206 22uf 200V
R7206 in parallel with C7207 22uf 200V

The two LED power supplies in this are stacked together, one is generated by T7601, the second power supply is the Boost converter generated by L7201 and Q7201.
All 4 Cathode returns are tied together return to via Q7202, and current sensing resistors.
So those resistors cannot be that low of the resistance, more like the 68K and 100K are to be the correct value. Those caps are rated at 200V so the I expect the Voltage between the two legs of those cap will be in 150V range.
You said the resistors blew up, what are the resistance reading of the original resistors?
https://www.shopjimmy.com/sharp-runt...led-board.htm#
Pictures provided by shopjimmy.

[djpat1974]

Re: (DPS-168JP A) Power Supply / LED Board LC-60LE600U

yes that is what the plugs look like sir the original resistors got thrown out by mistake what a mistake