Dynex dx-22ld150a11 LCD TV No Power Dead

[budm]

Re: Dynex dx-22ld150a11 LCD TV No Power Dead

I edited my post #19 after blowing up the pictures to see the traces more clearer, please read my post again. Try lifting the pin instead or try lifting up one end of ZD101.

[arman960]

Re: Dynex dx-22ld150a11 LCD TV No Power Dead

OK, much better pictures with less reflection.
Correction! I look real close at the picture, pin 7 is connected to J7 jumper, and it is ALSO connected to C104 to ground and also ZD101 to ground.
So best thing to do is to lift pin 7 off the board.
So the short can be the IC, C104, or ZD101.

should I just go ahead and remove the whole ic? I am afraid I might break the pin 7 , it is so tiny.

[arman960]

Re: Dynex dx-22ld150a11 LCD TV No Power Dead

I edited my post #19 after blowing up the pictures to see the traces more clearer, please read my post again. Try lifting the pin instead or try lifting up one end of ZD101.

ok removed ZD101 and J7 , took the resistance between GND and 7 still same 3.5 Ohm

[ben7]

Re: Dynex dx-22ld150a11 LCD TV No Power Dead

ok removed ZD101 and J7 , took the resistance between GND and 7 still same 3.5 Ohm

I sugguest you remove the chip and measure the pins. I can remove these tiny chips by getting some extra solder on all the legs, and then by heating up four pins (i.e. pins 1-4 and pins 5-8) at a time, I can lift the chip up, and heatup the other 4 and remove the chip.

There is still a transistor that is connected to the pin 7, but, the chip is likely fried. Seems strange for it to fry in this way - once you get a new chip (if this one is bad), I think you should measure the voltage from pins 7 to GND.

[budm]

Re: Dynex dx-22ld150a11 LCD TV No Power Dead

You can also measure the pin 7 pad on the board and ground after the IC is removed, if it does not read 3 Ohms any more, then the IC is shorted out for sure.
I will draw up the diagram of the IC connections later on for you.

[arman960]

Re: Dynex dx-22ld150a11 LCD TV No Power Dead

ok I just removed the IC and measured the resistance between GND and pin 7 still same 3.5 Ohm. So could be wrong?

[ben7]

Re: Dynex dx-22ld150a11 LCD TV No Power Dead

ok I just removed the IC and measured the resistance between GND and pin 7 still same 3.5 Ohm. So could be wrong?

You measured it on the PCB, or the chip?

If you measured it on the chip, that chip is fried.

If you measured it on the board, something other than the chip is fried.

[budm]

Re: Dynex dx-22ld150a11 LCD TV No Power Dead

If you measure at the pad for pin 7 on the board and it still shows 3 Ohms, then more likly to have shorted out MLCC C104 or Zener ZD101 which are connected between pin 7 and ground, the transistor for the VCC is not connected to ground at all.

[arman960]

Re: Dynex dx-22ld150a11 LCD TV No Power Dead

I measured board the GND and pin 7 WITHOUT the ic== result open circuit


But only the IC's GND and pin 7 still showing 3.5 Ohm

does it mean the IC is defective?

[budm]

Re: Dynex dx-22ld150a11 LCD TV No Power Dead

You have bad IC, PIN 7 is shorted internally to the Ground pin.

[arman960]

Re: Dynex dx-22ld150a11 LCD TV No Power Dead

what should be the normal resistance if it was good IC? I will order one IC than.

[budm]

Re: Dynex dx-22ld150a11 LCD TV No Power Dead

According to the spec of the VDD section with Gate drive pin open, the current draw is 2.7mA, so if the running voltage around 15V, that means the active resistance will be around 5.6K Ohms.

[arman960]

Re: Dynex dx-22ld150a11 LCD TV No Power Dead

I ordered one IC from digikey. . Lets see what happens when I put it on the board.

[RWolfe8970]

Re: Dynex dx-22ld150a11 LCD TV No Power Dead

hello there, I was reading your information on the Dynex dx 22ld150a11 Im looking to see if anyone knows where I can get the back light bulbs for this machine

[RogueCapacitor]

Re: Dynex dx-22ld150a11 LCD TV No Power Dead

Hi arman960,
I was wondering if you ever were able to fix your issue?

Cheers,