Samsung 32" LED TV UE32F5300AK sound no picture

[safesurfer65]

Hi all

Have a 32" LED TV UE32F5300AK that has sound but no picture or backlight.
Tried a factory reset using the remote with no joy. See below for measurements taken from the PSU to Main board connector

PIN1 B13V – 12.85V
PIN 2 PWM_DIM – 4.7V
PIN 3 B13V – 12.85V
PIN 4 ECO_ON/OFF – 0V
PIN 5 Vamp – 12.85V
PIN 6 BLU_ON/OFF – 4.7V
PIN 7 Vamp – 12,85V
PIN 8 GND – GND
PIN 9 GND – GND
PIN 10 GND – GND
PIN 11 B5V – 0V
PIN 12 A5V – 5.2V
PIN 13 B5V – 5.2V
PIN 14 PS ON/OFF – 3.3V

Any ideas ?

Thanks

Mark

[nomoresonys]

Re: Samsung 32" LED TV UE32F5300AK sound no picture

see the tcon?, the last pic., looks like a fuse there, try checking that fuse with a multimeter. check anything labeled starts with F, F=fuse.

[paulstef]

Re: Samsung 32" LED TV UE32F5300AK sound no picture

BLU_ON_OFF and PWM_DIM, how do they behave when you turn on the TV ? From standby to ON I mean? They look like the control signals for the backlight.

If they change I would assume the problem is on the PSU board. The voltage for the LEDs is probably coming from a separate winding of the main transformer, could then be boosted with the little coil on top...

What,s underneath the board? If you can find an LED current controller chip that's a good start from there you can draw parts of the circuit, single layer board shouldn't be that hard.

[safesurfer65]

Re: Samsung 32" LED TV UE32F5300AK sound no picture

Hey guys

Thanks for the help. The fuses on the T-Con all seem fine. The BLU_ON_OFF and PWM_DIM do change when switched on from standby. I checked the connector from the PSU to the screen and I can only get a voltage on 1 pin and its varies from 190-220v. I also checked the 220v 45uf capacitor at the top right of the PSU (near the screen connector) and its only measuring 119v. Does this suggest a faulty PSU ?

Many thanks

Mark

[tom66]

Re: Samsung 32" LED TV UE32F5300AK sound no picture

More likely is open circuit LED in screen. Another one like this! Very new set (2013 generation, F-series)

Check all the LED returns (LED- or LEDK marked), should be only a few volts each, but none should be zero...

[safesurfer65]

Re: Samsung 32" LED TV UE32F5300AK sound no picture

Thanks Tom

I'll give that a try but there doesn't seem to be an easy of accessing the pins with the plugs in place.

cheers

Mark

[nomoresonys]

Re: Samsung 32" LED TV UE32F5300AK sound no picture

seems like the led's have a lot more trouble than lcd's, I think I'll stay away from led's for personal use.

[tom66]

Re: Samsung 32" LED TV UE32F5300AK sound no picture

Definitely...

At least CCFLs rarely failed before they were due (I can't recall a single panel with failed CCFLs with less than 20khours)

The LED chips seem to be experiencing much more common random failure -- they fail less perhaps on average, but since the set is dependent on any one being functional, failure of the backlight system is much more common.

And unlike on a CCFL TV... where the power board may fail which is relatively easy to fix... replacing LEDs in a panel is very difficult to do right.,.