Samsung UN75F6300AF help

[jxgx]

Re: Samsung UN75F6300AF help

There is a short in places on the bar the lights attach to between + on one strip and - on an adjacent strip. 8 places have it and 3 don’t. For example, 1&2 have it 2&3, 3&4 don’t, 4&5 do etc. this is all with the ps not in.
Yes to storyteller. The black sheet has never come off. I slid a thin cutting board under the ps while I was testing it. No, they only light up with it disconnected from the board and unplugged from mother board.
Biruslapio, at to 200m setting, I do get readings on + or - ‘to the base on several of the main strip connectors.

[jxgx]

Re: Samsung UN75F6300AF help

I couldn’t determine if I really had a short or if my meter was being erratic. I did still get the weird readings between strips I described above. I disconnected the light strips from the bar and reconnected them. I couldn’t find any fault in how they were assembled. I-installed the power supply and plugged it into the mother board to test it that way. Now, all the lights come on and stay on. They all dim the same after several seconds and stay on. Did I inadvertently fix something? Is it normal for them to dim? I’m not sure if I should put it back together or not yet.

[howardc64]

Re: Samsung UN75F6300AF help

There is a short in places on the bar the lights attach to between + on one strip and - on an adjacent strip. 8 places have it and 3 don’t. For example, 1&2 have it 2&3, 3&4 don’t, 4&5 do etc. this is all with the ps not in.
Yes to storyteller. The black sheet has never come off. I slid a thin cutting board under the ps while I was testing it. No, they only light up with it disconnected from the board and unplugged from mother board.
Biruslapio, at to 200m setting, I do get readings on + or - ‘to the base on several of the main strip connectors.

Picture would be helpful... label your test points.

Some of the strips could be connected in series so beware how you are doing your short testing. Some + could be series connected to -.

Your description in post #11 shows no short on the LED strips (unless they've been shorted since due to improper testing) fully connected with the vertical bar. The short is between the strip/bar and the chassis.

Here is shopjimmy's pictures

https://www.shopjimmy.com/search.php...UN75F6300AFXZA

PSU board shows there are 4 circuits on each of the 2 LED connector (T1-T4, B1-B4 (hard to read if is B)) for total of 8 circuits. Since there are 12 strips (the 3 segment of each strip looks like its in series from the shopjimmy's picture) Likely 4 of the 8 circuits is driving 2 rows of lights. Testing the LEDs from the PSU connector is tricky. Need to inject the + - into correct pins on the narrow connector next to each other and LEDs are on the other side of the 75" chassis. A helper is probably desirable. I always do this step to make sure every LED circuit lights up at the connector from the PSU. But tricky as noted without enough hands.

To check short against chassis, you want to have 1 probe on chassis, the other on each of the 8 + on T1-T4 and B1-B4. If a + bad breached a short to chassis, your meter will beep in diode mode (if you have one that beeps) or show nearly 0 ohms.

[Biruslapio]

Re: Samsung UN75F6300AF help

I couldn't determine if I really had a short or if my meter was being erratic. I did still get the weird readings between strips I described above. I disconnected the light strips from the bar and reconnected them. I couldn't find any fault in how they were assembled. I-installed the power supply and plugged it into the mother board to test it that way. Now, all the lights come on and stay on. They all dim the same after several seconds and stay on. Did I inadvertently fix something? Is it normal for them to dim? I'm not sure if I should put it back together or not yet.

Now it is operating correctly, the TV turns on with 100% peak brightness, then dims it because there is no signal input on the mainboard, it means it is not shorted, for now, it may or may not come back if the strips move to the bad spot or whatever was causing it.

[jxgx]

Re: Samsung UN75F6300AF help

I tried to make it short again but gently I guess, I didn’t want to create problems either. It’s assembled and working so far.
I sincerely thank all of you for helping me and teaching me. I know you didn’t have to. Thank you, thank you!!!