Re: rca rlded5078a-d
Update; I was able to use an old ATX power supply to supply each LED with 3.3V.
6 of the LEDs were burnt out, the odd part is that the first LED on all 5 strips were burnt out plus 1 part way into one of the strips. Would this indicate an over voltage problem?
dpcookson
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Last Activity: 02-03-2025, 04:42 PM
Joined: 09-13-2015
Location: Ontario
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Re: rca rlded5078a-d
GND lead of the DMM was on the GND circuit of the board. On power up, the voltage at the LED connector started at +0.69V then about 3-4 seconds later it "dropped" to -394V, then returned to +0.69V. With the unit powered off there is 0V at the LED connector. I suppose it doesn't matter which side of the LED circuit is positive or negative, as long as the LEDs polarity matches.
I realize that an LED is a diode but maybe I was checking them wrong with my meter, if you look at my previous posted pictures, I was connecting my leads to each...Leave a comment:
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Re: rca rlded5078a-d
It is full backlight, there are 5 strips of 14 LEDs.
[ATTACH]118819[/ATTACH]
[ATTACH]118820[/ATTACH]
note: The TV is "upside-down" in the picsRe: rca rlded5078a-d
It is full backlight, there are 5 strips of 14 LEDs.
[ATTACH]118819[/ATTACH]
[ATTACH]118820[/ATTACH]
note: The TV is "upside-down" in the picsRe: rca rlded5078a-d
It is full backlight, there are 5 strips of 14 LEDs.
[ATTACH]118819[/ATTACH]
[ATTACH]118820[/ATTACH]...Last edited by dpcookson; 09-16-2015, 09:01 AM.Leave a comment:
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Re: rca rlded5078a-d
Okay, measured the LED connector during power cycling and got -394V (why is this negative?) but it dropped out quickly like you guys said it might.
If this is a sign of a bad LED or more how do I check them? I tried setting my DMM to diode to test a few random ones but didn't seem to get anything.Last edited by dpcookson; 09-16-2015, 07:48 AM.Leave a comment:
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Re: rca rlded5078a-d
It just so happens that I already have mine tore down that far, I could test my strips if anyone can point me in the right direction.Leave a comment:
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Re: rca rlded5078a-d
Thank you budm for your time so far. I monitored the voltage on pin 9 while powering the unit on and off a couple times but there was no change.Leave a comment:
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Re: rca rlded5078a-d
IC1F is a BD9211F
I don't honestly know what I'm looking for to test this component so I took some voltage readings with my DMM while the board was wired up and powered on.
Pin # = VDC
1 = 11.14
2 = 4.15
3 = 0.001
4 = 1.465
5 = 0.023
6 = 0.020
7 = 0.001
8 = 0.096
9 = 0.001
10 = 3.495
11 = 0.001
12 = 0.001
13 = 0.003
14 = 0.002
15 = 0.025
16 = 0.001
17 = 0.001...Last edited by dpcookson; 09-14-2015, 07:24 PM.Leave a comment:
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Re: rca rlded5078a-d
Okay, thanks for the suggestion. I'll take a look hopefully tomorrow night and see what I can find.Leave a comment:
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Re: rca rlded5078a-d
22.3 nf
Seems this cap is right on spec from what I have researched on it. Guess it's back to the drawing board, lol. Thanks for the help, I'm pretty new to this stuff so I appreciate any info I can get.Leave a comment:
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Re: rca rlded5078a-d
Bear with me please, I am by no means an expert here, nor even a seasoned novice, lol.
Please correct me if i am mistaken,
After following the board layout according to SJ's pictures I have found that C10F may be the culprit as I have 358 VDC on the "south" side of the (cap?) but only 0.398 VDC on the "north" side.
Suspect device "C10F" is located below T2F (transformer at top of picture) on "HOT" side of board.
[url]http://www.shopjimmy.com/proscan-ay128d-4sf51-...Leave a comment:
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Re: rca rlded5078a-d
Sorry, don't mean to hijack this thread but I am curious if the OP solved their problem as I am experiencing the same issues with an identical board; my voltages to the LEDs read .689vLeave a comment:
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