52"RCA Problem.

[wadenvk]

Re: 52"RCA Problem.

Alright I tested the big cap dc v light on 169v light off starts high drops to 169v. here is a better pic of the board.

[johnboy1313]

Re: 52"RCA Problem.

OK, it looks like something is keeping your PSU from coming up. It could be a faulty PSU, main board, or LEDs in the panel. I'm guessing that the two harneses (CON5 and CON6) at the bottom of the power supply connect to the LEDs in one way or another. Try disconnecting them and powering the TV on. Check the voltage across that big cap again. If no change, unplug the set from the wall and use two resistors roughly 1K ohm to force the PSU on. Plug CON5 and CON6 back in and unplug CON2 and CON4 from the main board. Leave them plugged into the PSU. Push the end of one of the resistors intp the end of the CON2 connector for the wire that is connected to the +5Vsb line. Bend it over and push the other end into the hole for ON/OFF. Push one end of the other resistor into the CON4 connector for the pin labeled BL-ON and wrap the pther end of the resistor around the other resistor where it is pushed into the +5Vsb hole.

Kind of like this.
https://www.badcaps.net/forum/attach...6&d=1355670365

When that is done, plug the set in and measure across that cap. The backlights should come on. If they don't or the PSU doesn't power on, try unplugging CON5 and CON6 again (with the TV unplugged and the main cap discharged) and trying it again. If the big cap does show 390V, measure your 12V and 5V pins. If there's power, your PSU is probably fine.

[wadenvk]

Re: 52"RCA Problem.

Alright I unpluged cons 5-6 Light on 169vdc light off 394vdc. Thank you for the help.

[wadenvk]

Re: 52"RCA Problem.

Now that I have 390 on the cap. I tested the plug.
12v= 11.92
12v=11.93
+5v=4.98
+5v=4.98
5vsb=4.98
on/off=4.64
+5v=4.97

[johnboy1313]

Re: 52"RCA Problem.

So, it seems something in the panel is shorted. Try unplugging CON5 or CON6 one at a time. It may not work at all or it may light half of the panel. You can also try testing for a short between one of the three red wires in each of those connectors and probably the black wires. Honestly, I'm not sure what the white wire is. Are there any pin labels for those two connectors? While you're there, look at those wires that run into the panel at the bottom. Maybe one of them has worn through the casing and is shorting against the back of the panel. You are more than likely going to have to open the panel and look for shorted LEDs but you might get lucky and find a short in the harness itself.

[johnboy1313]

Re: 52"RCA Problem.

Also, it looks like CON5 is slightly damaged. Did you do that?

[wadenvk]

Re: 52"RCA Problem.

CON 5 has a black mark on it's not damaged. I tried Unplugging them one at a time with CON 6 there was no flash but lost 12v, with CON 5 there was a flash and lost 12v. I will start looking for a short now.

[johnboy1313]

Re: 52"RCA Problem.

I'm just guessing, but maybe the LEDs on CON6 are trying to start before the PSU is shutting down due to a short detected on the CON5 side of the panel. At least that's where I would start.

Now that I think about it, if CON5 isn't even plugged in, I may be wrong. I really don't know. Just thinking out loud I guess.

[wadenvk]

Re: 52"RCA Problem.

I have been looking for shorts. Have not found any yet. You can think out loud I think we are narrowing it down some.

[johnboy1313]

Re: 52"RCA Problem.

How comfortable are you with opening the panel?

[johnboy1313]

Re: 52"RCA Problem.

Can you tell me what is written directly under CON5 or CON6? If they're pin labels, I'd really like to know what the white wire is.

[wadenvk]

Re: 52"RCA Problem.

I already have the panel opened up, Here are pic's of the two plugs.

[wadenvk]

Re: 52"RCA Problem.

The reds are positive the other's are neg. No shorts between them.

[johnboy1313]

Re: 52"RCA Problem.

Do the red and black wires plug into another board inside the panel? With the screen off, you should be able to see which LEDs are not lighting. Or, you can test each led with your meter on diode mode. Once you've found the bad one(s) you might be able to replace it/them with a resistor/resistors.

[wadenvk]

Re: 52"RCA Problem.

he wires go directly to the led's I can get each side to flash plugging or unplugging CON 5 and 6. I have two strip's of led's that do not flash but I cant find anything wrong with them. I marked the led's that are not flashing.

[onairhandyman]

Re: 52"RCA Problem.

Is it possible that the strips that are not lighting up are causing an open circuit of some sort?

[johnboy1313]

Re: 52"RCA Problem.

Yes, that's very possible. Look closely at each LED. I once had an LED flashlight that failed because one of the LEDs burnt. It was easy to tell the burnt one. That was my experience. You might have to check each one, individually, with your meter on diode mode.

[johnboy1313]

Re: 52"RCA Problem.

I would start by checking several of the LEDs on one of the good strips to establish a baseline. Check them both ways with the black lead on one leg and then on the other leg the next time. Then check each LED on the bad strips the same way. Look for those that differ substantially from your baseline.

[wadenvk]

Re: 52"RCA Problem.

Ok I will check them I can not see any that look burn't. The led's are sealed to the strip How do I go about testing each led.

[johnboy1313]

Re: 52"RCA Problem.

That I'm not sure of. Can you remove one of the strips without ruining it? If so, post a close up pic of each side of one of the LEDs and we'll have a look.