22me402v led tv strobe light effect

[ecking767]

Re: 22me402v led tv strobe light effect

Yep thats it! Was that you're problem with yours?

no I haven't repair that TV yet, I was just doing a quick check of the boards inside. my problem was no display. haven't got back to it

[freakaftr8]

Re: 22me402v led tv strobe light effect

Well new power supply is in. Still doing the same thing. So power supply is ruled out. Ehat else.should I look for that will cause the strobing on the led backlight?

[Ltank]

Re: 22me402v led tv strobe light effect

I have seen this syptom before on a Vizio TV. Check your large electrolytic caps on the iverter board They will have a high ESR. May not even be bulged. usually as ESR changes so does the value of capacitance that affects the timing of the oscillator circuit.

[freakaftr8]

Re: 22me402v led tv strobe light effect

Thanks for the reply. Its an led tv thou. All the voltage conversion is done on the power supply. It only needs 40v to power the led strip

[freakaftr8]

Re: 22me402v led tv strobe light effect

I forgot to mention that when the backlight adjustment is all the way up the voltage coming out of the BL_adj is 3.3v. On the mainboard out to the ps. when the backlight adjust is all the way down in the menu the voltage is .6v. so it appears the main board is doing its job. Which only leaves me to believe that there's something wrong in the LED strip somehow. Is there a way to verify this?I tried unplugging the mainboard and of course there's no backlight at all or no picture so it's really hard for me to tell what could possibly be going on here but it's definitely not the power supply

[freakaftr8]

Re: 22me402v led tv strobe light effect

Has anyone ever has a problem with the led backlight? What normally are the symptoms of a defective led backlight?

[freakaftr8]

Re: 22me402v led tv strobe light effect

This tv is buggin me. All voltages test within spec. 2 different power supplies and same fault. BL_adj goes from 3.3 to .5v with backlight level in menu so the power supply is getting its full 3.3 volts but for some reason the lights are dim and flickering. I texted each led with my meter and they all home within spec and all lit up bright in diode check mode. but yet when all connected the lights are flickering dimly. the power supply has BL_sw and bl_adj both getting full 3.3 volts. All the other pins seem like they're doing what they're supposed to do according to the label on the power supply.

[freakaftr8]

Re: 22me402v led tv strobe light effect

I got bold and pulled the backlight cable while on. Rocking it back and forth shows that 1led 1 2 3 and 4 act lije a ground and center pin is the 44vdc. As I rock it the outer pins make the screen dimmer and brighter. Its turning on and off the four banks in the strip

[freakaftr8]

Re: 22me402v led tv strobe light effect

Well tv now has a new mainboard and power supply. Still flickering.like a mad strobe light. Its definitely in the led strip but im not seeing how its possible. Diode tested every led and came up the same on my fluke. And all light up in the tv and diode test. What gives?

[Redion]

Re: 22me402v led tv strobe light effect

Hey there

I am working on the same power supply as yours. My symptoms are loud squealing and ticking sound. May I ask what did you repair in your original PSU to get it to work?

- All caps in spec
- All diodes ok
- All through hole resistors okay
- All SM fuses okay
- All transistors measure okay (i think)
- Transformer T601 has continuity
- Suspecting IC001 "HAI 7209PC" to be the cause...

[freakaftr8]

Re: 22me402v led tv strobe light effect

Well the parts for my supply were more than the supply was worth so I purchased a replacement. But if yours is squealing disconnect ribbon to mainboard. Does squealing stop? I had another one of these that caused the power supply to do that and it was actually a mainboard issue. But my original issue was main mosfet blown in hot section of power supply and 2 zener diodes.

[Redion]

Re: 22me402v led tv strobe light effect

When the main board is disconnected the squealing stops...
As soon as ribbon is plugged in the right pitch noise is right back on...
Now I am not sure if I should buy the main or the PSU...

[freakaftr8]

Re: 22me402v led tv strobe light effect

Do you have a standby light when this happens? Unplug mainboard and check pins for 5v on power supply. If you have 5vdc suspect mainboard to be at fault. . I have a mainboard here at home that causes the ps to squeal and it does not provide a standby light.

also try with mainboard connected and led strip disconnected.

[Redion]

Re: 22me402v led tv strobe light effect

Will try tomorrow... I will let you know!
Thanks

[freakaftr8]

Re: 22me402v led tv strobe light effect

Ok got in tbe new led strip and guess what... Still doing the stribe light!!!! Thats all boards replaced now. Im really srumped. I swapped ps twice too. One I thought was rhe prob. Next.one still did it. bew mainboard and led strip that I personally saw work perfect in another panel.

[tw2005]

Re: 22me402v led tv strobe light effect

What's it like at max brightness? Could it be that the LED brightness is controllled by pulsing the LEDs and maybe it's just a poor design?

has anyone else viewed the TV and also sees the same strobing effect?

Just throwing some thoughts out there?

[freakaftr8]

Re: 22me402v led tv strobe light effect

No actually at max backlight the pulses seem to get worse actually. This is odd. it's also something that I can't pick up on a camera for video and actually show because the pulsing in the flickering itself at the camera can't pick it up

[freakaftr8]

Re: 22me402v led tv strobe light effect

Yes had 2 friends look at it. They both say its messed up. The strobing is not steady. Somerimes tgr backlight briefly cuts out and I can hear this in tandem with the power supply ticking.
its not bright by any means.
The picture is quite dimly lit.

[tw2005]

Re: 22me402v led tv strobe light effect

yeah, awefully unlucky still having the problem replacing everything then . Don't have any experience really with backlit panels to be of much help sorry.

[tom66]

Re: 22me402v led tv strobe light effect

Have you jumpered the BL ON and DIM signals to rule out the main board?