Ocosmo E32 no backlight

[taman]

I have an ocosmo model E32, p/n CE3200-WX2201P7A with a control/power supply board: B13073811-1A03980 HV320WX2-201 rev A1.

Picture and sound are present, but no backlight. On power-up, the backlight voltage goes up to about 125vdc and then quickly drops to 48.5vdc and is steady there. Adjusting the brightness has no effect on the backlight voltage.

Is this proper behavior and voltage for the backlight?

[dick_barton]

Re: Ocosmo E32 no backlight

Do the leds (backlight) flash briefly on power up?

[taman]

Re: Ocosmo E32 no backlight

The backlight does not flash.

[dick_barton]

Re: Ocosmo E32 no backlight

Can you provide pictures of your boards which could prove helpful.

[taman]

Re: Ocosmo E32 no backlight

There are 3 LED backlight strips with each strip having 7 LEDs. All of the LEDs are wired in series and one LED on one strip is bad, therefore, no LED flash on power on or ever. The LED strip has the following numbers on it:
SJ32L321-DH-13052201
Y5JC032
IC-B-HWA032D255

Does anyone know what the LED is or if the LED strips are available?

Photos of the control/power supply board and an LED strip are attached.

[taman]

Re: Ocosmo E32 no backlight

I removed the lense and the LED measures 3.4mm x 2.8mm and is 0.85 mm tall. Picture attached.

[taman]

Re: Ocosmo E32 no backlight

Shorting out the defective LED, the backlight drive is 77.7Vdc @ 347ma, driving 20 LEDs. That gives a Vf of 3.885V.

The brightness setting was set to maximum before I disassembled the TV.

The part size I stated earlier should probably be 3.5mm x 2.8mm which is a 3528 metric or 1411 imperial smt size.

[taman]

Re: Ocosmo E32 no backlight

One interesting note: when I adjust the brightness, the voltage and current on the backlight LEDs stays the same. I would expect the current to decrease.

[budm]

Re: Ocosmo E32 no backlight

One interesting note: when I adjust the brightness, the voltage and current on the backlight LEDs stays the same. I would expect the current to decrease.

Brightness adjustment is not the same and Backlights level adjustment.
You need to adjust the Backlights level.

[taman]

Re: Ocosmo E32 no backlight

I don't see an adjustment for backlight level. How do I adjust the backlight level?

[taman]

Re: Ocosmo E32 no backlight

TV is fixed. I used a Samsung LM301a 3x3mm LED with a CCT = 6500K. Things I note:
1. The existing LEDs appear to have a higher CCT because the corner of the display where the new LED is placed is a little yellow compared to the rest of the screen. 6500K was the highest CCT that was offered for the LM301a.
2. The intensity of the new LED is a little greater than the existing LEDs which was noticeable on the bench, but not in the TV.

[somaraok]

Re: Ocosmo E32 no backlight

Hi All,

I had the same issue. One of the LED on one of 3 strips dead. So, I went to electronics market and just brought 3 strips (7 LEDs in each) and replaced. Only thing is you may not get new strips with same connector. I just cut the existing connectors and soldered directly on new strips. I had to bend new strips as they longer than existing ones. Now TV brightness and clarity is a lot better then the original.