Samsung UN39FH5000F has sound but no picture

[frannyjunk]

Hi, I have an old tv that has sound but no image. No image even with flashlight. These are the things I have tried:
- Unplugging cable from power supply board to main board resulted in backlights lighting up (tv was on at this point). This likely means that LED strip are ok
- Used backlight tester on leads on power supply board. Both LED strips showed 173V, and both lit up when tested. Yet nothing on tv screen except for a faint glow of the backlights
- Unplugging LVDS cables from T-Con to panel (first left cable, then right cable) did not show anything on screen. Backlight remained off
- When measuring voltage on power supply plug (to mainboard), all voltages (PS on/off = 5V, Blu on/off = 13V, PWM_DIM = 13V) were good for about 5-10 seconds, then all go to zero. And as mentioned, backlights remain off

Seems to me like a main board problem, but anybody know if this model is known to have a specific component fail on the main board? Given the age of the tv, if I have to buy a main board then it is not worth fixing.

Appreciate if experts on this board can advice. Thanks!

[dskall]

Re: Samsung UN39FH5000F has sound but no picture

What happens when you unplug cable from main to t-con?

[nomoresonys]

Re: Samsung UN39FH5000F has sound but no picture

if you havent already, maybe check fuse on tcon board, see if you have about 12 volts on each side of fuse, use metal chassis back for ground, for those that may be looking on, I can tell you know how to test.

[frannyjunk]

Re: Samsung UN39FH5000F has sound but no picture

What happens when you unplug cable from main to t-con?

TV has same symptoms as before. Sound but no video. Backlight stays off.

[frannyjunk]

Re: Samsung UN39FH5000F has sound but no picture

if you havent already, maybe check fuse on tcon board, see if you have about 12 volts on each side of fuse, use metal chassis back for ground, for those that may be looking on, I can tell you know how to test.

Fuse has connectivity and measures 12.9V. I think the T-Con board is ok. Is there a particular component I should check on the main board? TV powers on, then powers off after about 10 seconds (and backlights remain off during the 10 seconds).

[nomoresonys]

Re: Samsung UN39FH5000F has sound but no picture

heat up your eeprom with a hair dryer its probably labeled IC901, for a couple minutes, then try the tv, see if anything changes, do not wait til it cools down, try it straight away.

[nomoresonys]

Re: Samsung UN39FH5000F has sound but no picture

maybe look closely at your big chip, it looks a little funky, if its cracked or has a hole its probably bad.

[frannyjunk]

Re: Samsung UN39FH5000F has sound but no picture

maybe look closely at your big chip, it looks a little funky, if its cracked or has a hole its probably bad.

Thanks Nomoresonys. Tried heating IC901 and the big chip. Also tried pressing hard on the big chip. I think it is time to punt on this project. I just hate the idea of putting it in the landfill.

[nomoresonys]

Re: Samsung UN39FH5000F has sound but no picture

theres a bunch of mainboards there for 25 bux each: https://www.ebay.com/sch/i.html?_fro...acat=0&_sop=15

[frannyjunk]

Re: Samsung UN39FH5000F has sound but no picture

theres a bunch of mainboards there for 25 bux each: https://www.ebay.com/sch/i.html?_fro...acat=0&_sop=15

Thanks!