Samsung UE32D5520 buzzing PSU, no picture

[fejlong]

Re: Samsung UE32D5520 buzzing PSU, no picture

Connected PS_ON to 5V and there is 12.7V on Vamp, B13V and 5.3V on B5V. These voltages are here with or without connecting PS_ON to 5v. Backlight does not come on though. Voltage at CNL802 118V on both cases.

[dick_barton]

Re: Samsung UE32D5520 buzzing PSU, no picture

What is the voltage at Pin 1 of IC9101 with the mainboard disconnected and the 1K resistor in place????

[fejlong]

Re: Samsung UE32D5520 buzzing PSU, no picture

Main board disconnected, PS_ON connected to 5V through a 1k resistor.
Voltages on Vamp and B13V are 12.7V
Voltages on A5V and B5V are 5.3V backlight is off, won't come on.

The same voltage readings can be measured even if PS_ON is not connected to 5V

[dick_barton]

Re: Samsung UE32D5520 buzzing PSU, no picture

What is the voltage at Pin 1 of IC9101 with the mainboard disconnected and the 1K resistor in place????

[fejlong]

Re: Samsung UE32D5520 buzzing PSU, no picture

12.7V is on pin 1 of IC9101 with main board disconnected, with or without resistor connected.

[dick_barton]

Re: Samsung UE32D5520 buzzing PSU, no picture

With the same setup as above, ie mainboard disconnected and 1K resistor in place, what is the TOP1+ voltage when you turn on the power supply.

[nomoresonys]

Re: Samsung UE32D5520 buzzing PSU, no picture

Strange, maybe try with cable from powerboard to mainboard unplugged, use about a 1k resistor from BLU_ON pin to standby pin, see if you get backlights up.

[fejlong]

Re: Samsung UE32D5520 buzzing PSU, no picture

Hi, thank you all for your replies. I got to the stage where I couldn't bare it anymore and I ordered a working power board. It arrived today, but makes the same silly noise as with the suspect power board. And it doesn't work. My next suspect is the back light LED's, anyone ever tried to repair such thing? Does it worth bothering? I will disassemble it anyway, but for the moment thus project is on standby.

[nomoresonys]

Re: Samsung UE32D5520 buzzing PSU, no picture

Well being a 32 inch and if for my own use, I would probably throw in some cheap used backlight strips or replace the little leds individually which are not expensive but require soldering and getting the lenses back on correctly and turn the backlight setting down as far as tolerable to your viewing likes if that is whats wrong. With the used stuff it could go out again pretty quickly BUT then you get to fix it again, what else to do during quarantine?

[nomoresonys]

Re: Samsung UE32D5520 buzzing PSU, no picture

Maybe do those suggested tests again with the new powerboard and see if anything reads differently.