Re: Toshiba 50L1350U only some leds out?
I used a supply that puts out very low amps and added a resistor. I am currently making a variable power supply. Until that's done, I have to improvise.
hfosteriii
Member
Last Activity: 03-18-2017, 07:32 PM
Joined: 03-06-2017
Location: North East
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Re: Toshiba 50L1350U only some leds out?
I tested the leds on half strips at 18 volts, individually at 3.6 to 4.3 volts. The two that were close together kept flashing on and off. They kept continuity, which is why the strip still worked. The strip that was out completely had one bad led, completely open, so no continuity.
I lucked out and found a LG LED tv with a broken lcd for 15 dollars, same part no. according to Shop Jimmy. So I took the leds off from that. Will replace tomorrow and report.
Thank you for the help.
HarryLeave a comment:
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Re: Toshiba 50L1350U only some leds out?
Question, is the forward voltage of the individual leds standard? I didn't know if smt Leda are the same as encapsulated leds. 3.2 volts or so each?Leave a comment:
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Re: Toshiba 50L1350U only some leds out?
I did understand your reasoning, budm, but I was (mistakenly) sure that we tested that course of action.
CheersLeave a comment:
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Re: Toshiba 50L1350U only some leds out?
First, I want to offer budm my formal apology. It seems I was working of of incorrect information when speaking on the leds. I was assured that they were all switcher out, but after thinking about it last night I had to ask my son, 16, if he actually did. He said he thought so. I checked and sure enough one strip set on each leg was not changed. So I retract my previous statement on that.
Second, I went ahead and changed them all myself this time, and I do indeed have some leds out. One whole r1 strip was out, and the last led on an...Leave a comment:
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Re: Toshiba 50L1350U only some leds out?
Btw, the voltages remain in the same state also.Leave a comment:
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Re: Toshiba 50L1350U only some leds out?
I'm sorry budm, but I took the led strips from 2, 3, and 4 (L2 leg),and switched them with the strips from 1, 5, and 6. I think I did use logic, in so far that the LEDs 2, 3, and 4 worked on L1's leg and the ones from 1,5,and 6 from leg L1 (that were lit) didn't work on leg L2. So that eliminates that. If they pull a load on leg L1 they certainly don't stop by switching them to leg two. Then I switched them back. All times L2 didn't work regardless of which led sets were installed, yet every time L1 did. The problem isn't the leds sir....Last edited by hfosteriii; 03-11-2017, 02:33 AM.Leave a comment:
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Re: Toshiba 50L1350U only some leds out?
Budm
" poor solder joints on the SMD connectors on the LED boards."
Do you mean somewhere in the led drive circuit on the power supply board?
Is it possible it's a shorted or blown resistor or cap in the smd section? Or the ic itself?Leave a comment:
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Re: Toshiba 50L1350U only some leds out?
I'll run jumpers to swap legs and retest components tomorrow. I did run some continuity tests in diode mode, while powered, and got some strange readings. L2- doesn't test continous or do anything with leads in either direction, but the others do something one way, different things in the opposite. I'll post results of that tomorrow.
It's starting to look like there's opened and closed gates in the OB3372KP, causing a short or open circuit respectively. Possible?Leave a comment:
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Re: Toshiba 50L1350U only some leds out?
When I switch the led strips to a working leg, they all work.
LED board continuity tests good.
Cable and both connectors are continuous.Leave a comment:
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Re: Toshiba 50L1350U only some leds out?
Budm
"Are you sure you do not have open circuit on the L2 string that is why it went up to 130V before the protection circuit kicks in and drop the Voltage down to 80V, check the inter connector between the LED board really well.
BTW, the LED Voltage (loaded) is 111V as printed on the board."
I'll check.
Jasonbay13
I'll swap l1 and two with some jumpers. Yes, mosfets ql1 and ql5. They both tested almost identical. I was concerned as the voltage kept creeping up. Forward voltage I think...Leave a comment:
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Re: Toshiba 50L1350U only some leds out?
Just looked at the led distribution board. Doesn't appear as though anything could go wrong. No components. No scratches in the circuit or breaks. If need be I'll test.
Thanks again.Leave a comment:
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Re: Toshiba 50L1350U only some leds out?
Here are the pics I promised. Hope they are correct. Should be high resolution. Let me know....Leave a comment:
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Toshiba 50L1350U only some leds out?
Hi guys and gals,
I'm trying to fix this Toshiba I have. The second, third and fourth rows of led strips are out. The television works fine other than that.
I've read through all of the posts here on the model I have and none seem to tell me what I need to know. Mind you, I'm trying to fix the problem, not replace the board if possible. If I have to in the end I want to be sure I get the right board, lest I spend money for nothing. I found the tv and I'm trying to fix ACAP (as cheap as possible)��.
I've checked much over and wrote down notes. I'm including a pic...Last edited by hfosteriii; 03-10-2017, 10:00 PM. -
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Hello,
I'm a mechanical/tech/media/ politics/food/total knowledge junkie. My interests span so far I do believe I have adhd. Haha. I quest for learning, everything and anything. I love tinkering, tearing down, fixing, designing, building, etc. and so on. I read constantly, while having news, YouTube, or a movie going in the background. The few thing I wish I had are more time in a day and a longer life, because there's so much to learn and get done. Looking to build relationships here for learning, teaching, helping...Leave a comment:
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