Great video, excellent analysis and reverse engineering of the circuit. You did all the hard work for me, all I had to do was select an appropriate inductor from my junk box and solder it in. Thank-you!
I have one of these as well, replaced the ic, mosfet, coil, and took your advice on replacing those sm resistors. I tired (2) 1/4 watt 5.6 ohm in parallel, but couldn't get the temp any lower than 190 F. I clipped one of the 5.6 ohm off and just went with one. Got the temp down to 130 F on the coil. I think this is as good as it gets. I think 1/4 watt is fine. Thanks for the video. It helped a lot.
I was in the same situation with a burned out L1 coil. I had assumed it was the caps and replaced them. When this didn't work I was about to give up hope. Thanks for this
You're welcome. I guess we all repair this way, check for the obvious first, caps, solder joints etc. I also wanted to give up but when I got 2 of them I thought it might be worth it.
Thanks for the help! Nice diagram, had the same issue. Burned out the Mosfet, the PWM chip was fine though. Replaced the inductor with one from a PC power supply but was getting only 40 volts out on the LED lead and it was heating to over 130 degrees! Hooked up the old inductor to my ebay build your own component tester and got .30uH the power supply inductor was only .07uH. I grabbed some inductor wire from the local electronics store and wrapped about 5 feet of it around the new PS inductor after removing the wire and tested it and got .17uH. This gave me 69 volts and then proceeded to remove the 1.2ohm resistor and added a 33 ohm resister ( with the 3.0ohm) for a 2.8 ohm final value. It works great, coil reaches 65 degrees but the insulation is rated for about 120c so should be good. Thanks!
Good it works. Do you mean you put a resistor in parallel with the 3R resistor? That would actually increase the LED current and they may become damaged more easily over time. I'd recommend to increase the overall resistance, in my case I about doubled it. (from 1.2||3 to 3.3||3.3)
Thanks for the reply! I did remove the 1.2ohm and put a 33 ohm in parallel. I figured that the resistance would be the same as adding 5.6ohm x 2 in parallel = 2.8 ohms. The 1.2II3.0 combo was 0.8 ohms. To duplicate the 2.8 ohms I took out the 1.2 and added the 33 ohm with the 3 ohm. It came to 2.8 as well. I thought using ohms law, the current would be the same but most of it would pass through the 3 ohm smd resistor but it can handle it at that current. I(t)=(I=V/R1) + (I=V/R2). I'm new to this and am trying to figure this stuff out. Let me know if I'm wrong? I also replaced the main filter cap as the ESR was high. Thanks again.
Ah ok, I didn't catch that you removed the 1R2 resistor. That's ok then. The only thing to observe would be power dissipation of these resistors, most of the current now goes through the 3R. Can't remember the average current though but I think it was pretty low... Shouldn't cause a problem. Cheers
that was fantastic! Entire video was informative, to the point, fat free and absolutely digestive. will follow up with details after attempting your suggested mods.
found a toroidal on a junked circuit board. a little larger but with about the same number of turns, maybe larger wire. looks like it was a filter for an audio output , possibly digital amp. also removed the point three ohm smd resistor from the other parallel one ohm ones, to decrease led current. end result, 31 volts in, 60 volts produced at led feed. Backlighting adequate, and coil and other parts running cool....
Heh,I knew I was saving all those pc power supplies for something.The heat melted the solder and opened the circuit.I temporarily put the coil back in.It lit ok,but the coil heated up.The board is a bit scorched,but seems ok.Nice video.
I didn't measure the inductance of the replacement inductor. However, current rises to 1.6A in 2us. I think I remember the boost circuit input voltage to be around 30V. Therefore the calculated inductance is 37.5uH. I think anything between 30uH and 50uH will work just fine. It needs to have the right current rating of course.
Me Tom it's me again on my way to buy the condutor which do you say is best don't wanna get to radio shack and be looking stupid please and thank you because those assholes might not know they just work there salesman it a hot chick usually so
James Bond Say you want a toroid inductor with a powdered iron core, inductance anything between 30 to 150uH good for 3 to 5 Amps. Still possible they won't know what you are talking about. Say you do not want a ferrite core. The ones I tested were all saturating.
merci, pour ta réponse oui le ic est le led driver et semble très difficile à trouver et la carte est plutôt dispendieuse compte tenu du prix de la télé . Au fait excellent travail ton video
Hey there. I tried your fix for this tv. Same board issues except the other two components burned out on your board aren't on my board. I used what you suggested, one from a PC pwr supply but way larger. This one has four leads in the board. I used only two of them but still no change in the tv. There is power at both leads of the replacement but still the tv stays off. I have pics of the repair I did but don't know how to get them to you to view. Where else might there be damage not visible?
you should be able to send me an email to tomtechtod (gmail). you seem to have a different board though, you say you don't have the transistor or controller chip? the four-legged inductor you used may be a common mode choke, don't know if this could work.
Hi, I am in the process of the repair and completely forgot to locate the orientation of the OB3350CP POWER PWM CONTROLLER. Can you please tell me where the dot is facing on the board, with the straight edge of the board facing up. I appreciate it very much.
+PHIL GIBSON Click on the "fullscreen" button of the youtube video, then on the little gear (that's the settings button). Adjust the resolution to 1080 (high definition). Go forward to 1:16 in the video, there is a picture , the controller chip is circled red and you can clearly see the direction it needs to be mounted.
Awesome video. got a new coil. changed resisters to two 5.6ohm like you did. when i give it power i hear a clicking sound and that's it(no power light of any kind). could this be the mosfet or controller you talked about that has gone too? they do not look burnt but its hard to tell.or its just something different all together. Thanks.
SegaMan001 repeatedly clicking or just once? To check the MOSFET measure its bodydiode from source to drain and gate to source resistance. What about the voltages? Do you have 12V? Does the primary controller work? Do you have a scope?
TomTechTod I do not have a scope. been meaning to get one. the clicking is every second. i am getting 1.3ohm on D to S and 3.5ohm on G to S. have not done much MOSFET testing before. when live the voltage over the MOSFET jumps from nothing to higher numbers every time it clicks. I will play with the primary controller and see what i can find. I may need to read into this some more. thanks
SegaMan001 1.3Ohm between source and drain means it's shorted/defective. My guess is the primary side tries to startup and sees a short on the output, hence stops and then restarts. The secondary boost controller may also be defective. I would first remove the FET and measure it again, then measure if there is a short form the controller output to secondary ground. If there isn't you may be lucky and it's just the FET. If you have any spare FET with over 100V VDSmax and a few amps IDS max give it a try before buying the original one.
Ça semble être le driver pour les DEL. J'en ai eu des cartes avec ce même chip sauté et j'en ai pas trouvé pour l'acheter. La seule manière d'après moi c'est trouver un IC pareil sur un autre board semblable ou acheter un board de remplacement. Trouver un board qui est exactement pareil (sur ebay par exemple) est quasiment impossible parce qu'il y a beaucoup de variations de cette carte, il peut même y avoir de cartes differentes dans le même modèle de télé... Pour une Proscan 32 pouces ça vaut pas la peine d'après moi.
I have a Proscan PLDED3273A-E with the same problem. If I only replace the inductor with one like the "Toroid Core Inductor Wire Wind Wound 150uH 42mOhm 5A Coil" will that be enough to fix the problem? Or do I also have to replace the resistors?
Hi Tom, first, just want to say thank you for the great effort in making this video. Nice and crispy and straight to the point. second, I have the proscan PLDED3273A-E TV which had the exact problem of inductor coil burnt out completely. I have no problem of fixing the coil but I would like to seek your confirmation or advice on the parallel resistors to be soldered on top of the 1R20 and 3R00 resistors. As the space on the PCB is kind of limited..is it correct that both 2.8 Ohms resistors are to be soldered together ie one leg of the 2.8 Ohms resistor is to be soldered to 1R20 resistor leg and the other leg of 2.8 Ohms resistor is to be soldered to the joint next to 3R00 resistor...Sorry that I am ametuer on this kind of DIY electronics stuff. Thanks a lot in advance for your advice.
Hi. I removed the SMD resistors and soldered the other two instead. Same location, just a higher resistor value. You have to remove the original resistors otherwise the LED current will even increase if you add anything in parallel to them.
+TomTechTod great stuff and it is very much appreciated Sir. I shall stick with your original advice using 2 x 3.3 Ohms resistor to replace the original 1R20 and 3R00 resistor. Thank you very much for your kind support and will update on the progress when I receive the coil...ebay shipment from HongKong.
Thank you for the great video. I did exactly what shown on your video, got it to power on with sound and the PROSCAN blue screen logo shows for a second. All functions are working, but the screen is dark. You can see what is on the screen in a dark room only. Please help me understand what I did wrong.
+Allan Aoukaty What is the DC voltage from cathode of D17 to ground and from anode of D18 to ground while the TV is on? If you have a scope: What's the signal on the gate of the FET?
Bruh ion know nothing bout this but RCA red light is on but It wont come on plus the power button is broken........... but it would definitely come on im just trying to figure out how........ do I gotta get a new broad ?
have a nice time sir! I just wanna ask if the PROSCAN 32"MODEL PLDED3237-G can plug it to 220v directly? The indicated power supply at the back is 100v-120v only. But the design in the power supply is like autovolt.The Filter capacitor is 400v/100uf. Pls consider my question.tnx in advance sir.
Great video! I have one of these hanging around with a fried (literally!) toroid for a while because I couldn't find any documentation showing the toroid value, and also didn't know that this problem could involve other parts of the board as you described. Did you say we can use a toroid inductor from any desktop power supply? Is there any way I could test the LED current controller and the MOSFET before replacing them? They are visually perfect and intact with none of those common signs of discoloration due to high temperatures as shown in your board (don't know if you damaged them after replacing the toroid inductor without making the modifications described). Anyway.... Thanks for the great tutorial! That certainly helped a whole bunch of folks including myself.
Thanks. I damaged MOSFET and controller after rewinding the old toroid core. It's an N-channel MOSFET. Simplest way is to do a diode test from source to drain (right pin to middle tab) , it should show the voltage drop of the body diode. Also test if there is a short from gate to source. My controller shorted out the power supply after I damaged it. It doesn't happen immediately so you could try to replace the coil first. The circuit is quite forgiving in terms of different inductance values and saturation levels. I would still try to use a core which is bigger in diameter so it can dissipate more and one that doesn't saturate like the first one I showed. There are so many ferromagnetic and ferrimagnetic core materials available it would be quite a challenge to find out what exactly is the best to use. As I said I prefered a straight current slope, a reasonable duty cycle (not too big, not too small) and relatively small peak currents.
TomTechTod Sou brasileiro sim! Você tambem é? Essa televisão foi comprada aqui em NY por um amigo meu que me pediu pra dar uma olhada depois que ela parou de funcionar. Meu conhecimento em eletrônica é muito basico mas as explicações dadas no seu tutorial simplificaram o problema consideravelmente. Vou ver se uso um indutor que vou tirar de um power supply de um PC que não uso mais e ver no que dá. Mais uma vez valeu a força! :)
I replaced the inductor coil with a slightly smaller one that I took off a working power supply from a different unit that had a broken screen. Some of the traces leading up to that actually got separated from the PCB a bit, but I continuity tested it after and it was a solid connection all the way through, so i'm assuming that wouldn't be the problem. Anyway, my problem before replacing the inductor was that the backlight wouldn't turn on. The weird thing is that I actually took the old broken coil out and the display would still turn on just fine, just with no light. Is the circuit that the inductor runs on only powering the backlight? Now that I replaced the coil i'm just getting a clicking every second or so, without a standby light or anything, so i'll just have to trace up to the point it would put that out probably. Another question, If I were to just take a secondary external power supply and hardwire it to the backlight, would there be any problems with that? This TV is honestly only going to be used in the back of a computer repair store, so it definitely doesn't need to be a practical or nice looking fix :p
+mookiedamouse2 1. the part of the circuit with the inductor in it is a booster for the LEDs (with current feedback) , so yes the rest of the TV could work without backlight 2. you need a current limiting power supply to power the LEDs, you could probably take one or two benchtop power supplies and put them in series and drive the LEDs with it. It should be in current limiting mode though. Since after your repair attempt it doesn't do anything anymore you need to find out first what's preventing it from turning on. Maybe the driver IC and/or FET is shorted, when you put in the inductor the primary side shuts off due to overcurrent . What happens if you remove the inductor and try to turn it on again?
+TomTechTod After I took the inductor out, the TV would turn on again. I took the inductor out of a few different power supplies and now know that the backlight circuit is the only thing wrong with them, but I don't have the tools in order to figure out what sort of new one to put in there, and how to actually get more of them, or know what they're rated at. I have one of the units put back together (without the inductor), and got the backlight wire to hang outside of the TV. I have quite a few CCFL power inverters here that were used for lighting in desktop towers, so they're powered from a 4-pin molex source. I don't actually know what the inverters are putting out, but I have 12v, 2a going in to it. Wired it all up and soldered the connector for the backlight wire to the end of the external power supply-thing I wired togeter, and surprisingly, it actually works! The backlight does definitely come on, but it's pretty weak. I have an extremely cheap volt meter (which I don't entirely know how to use), and it seems like it's putting out 8 volts, with an unknown amperage. We have a benchtop power supply that has 3 outputs. One of them is fixed (to something I know would be way too much), but the other two are variable output sources, ranging from 0-24v, and up to 600mA. Would any combination of that wind up being enough? Once I find out the magic stats in order to get the thing to light up properly, I can figure out what I need to do to make a few supplies to put that power out and get it all wired inside of the TV so it turns on with the rest of the unit just fine, i'm just lost when it comes to volts/amps/ohms/watts and any other sort of magical electrical terms that I like to pretend I understand. Thanks for the help!
+mookiedamouse2 1. Apparently the secondary MOSFET is shorted and therefore with the inductor in the circuit you are overloading the power suply. 2. A CCFL inverter output has way too much voltage, you probably didn't burn your LEDs because it cannot provide enough current to do so. 3. With 2 x 24V supplies in series you only get 48V. I think the voltage drop over the LEDs was about 70V so you would need an additional 24V power supply and put those 3 in series. MAKE SURE THERE IS A CURRENT LIMIT on those power supplies. LEDs are current driven devices. That means you would connect the 3 supplies in series and turn down the current limit to zero to begin with. Then increase slowly the current limit until the desired brightness is achieved. Don't make it too bright, this will increase the LEDs life expectancy.
Hello from Dave, I have the same tv, but I don't see any damage on the board, but the red light turns to blue when I turn it on.but again there is no sound and no picture.could there be a fuse that could be gone, and if so where would I look for this fuse. thank you for your time. Dave Mack
+Dave Mack I don't think it's a fuse. Please refer to the schematic contained in the video. You should be able to find the fault if you have a multimeter to take some voltage measurements.
If the new board is physically EXACTLY the same I would try to swap the memory chip from the old board to the new board, normally an SOIC8 near the microcontroller. Or you could repair the old board.
It's likely the PSU, yes. Could also be a shorted LED somewhere and the PSU detects this condition. Hard to say. These TVs are hardly worth the trouble witheir crappy mainboards...
Hi, I work in I.T. but one of my customer's brought his Tv such as the one you're working on and it doesn't turn on. Red light is on but nothing...he claims sometimes it does go "On", but not always. I took it apart but nothing looks off on the power supply, nothing burned..any suggestions?
I moved around the connector that goes into the power supply on one end and to the power cord on the other and tv turned on..i played around with it some more and it stopped turning on..i'm gonna redo some of the solder..usually i put motherboards with bad soldering into the oven for 10 minutes lol but looks like there are lots of plastic parts on the power supply which might melt..so i won't lol
I'm giving your video a thumbs up but my problem still persists i have almost the same model proscan i stripped it down to the LCD lights to see if that was the problem it was not the problem they all worked after putting it back together i put the old video board back on and it turned on but the picture lighting was to low on that board then i decided to replace the video board. Following the instructions to reset the board you have to plug it up and wait 5 to 10 minutes before hitting the power button it did not turn on i then switched back to the old board and got the same thing comes on but not enough voltage for the picture to show i just want to use the new board since everything is refurbished but it don't have enough voltage to even turn on the tv like the old board any suggestions?😐😐😐
Me to because i went through 4 just sending them back thinking that it was a manufacturer error but when you said change the swap the memory chip it dawned on me that could be the problem because when i plug it up the power light comes on but the tv don't fire up. I didn't switch it just yet but when i get time I'll let you know the outcome. Thanks in advance
"a bunch" sounds good because then you will have "a bunch" of working ones. Just lowering the LED current a bit will be ok. After watching it a while I found I maybe lowered it too much. I guess 2x3R3 or 2x4R7 in parallel may be better.
TomTechTod Hi Tom, I watched your youtube video regarding the RLDED3258A RCA LCD. Your end remark mentioned 2x3R3 or 2x4R7 in parallel may be better. Does this mean that the 2x5.6R in parallel are not necessary? That these lower values of resistors in parallel are fine? BTW: Great video and thanks for caring. Paul Taylor.
Originally there were 1.2 and 3 Ohms in parallel. I tested several higher values and found that with 2.8 Ohm the picture was bright enough. You can put in higher or lower values, depends on your preference (brightness). The higher the LED current the more the stress will be on the switching components and LEDs.
Après toutes les étapes, la télévision n'a aucun courant.. la lumière rouge a l'avant elle est fermée et lorsque j'appuie sur Power, aucune réaction. La seul chose c'est que la télévisions fait un petit "clic" a chaque 2 secondes environ et sa me vien pas des haut parleur mais plutôt la carte mère. svp si qqun pourrait m'aider. merci
+Nathan Mayer (NeeZiaa) As-tu remplacé le transistor et CI driver et la bobine comme décrit? Il faudra que tu prenne plusieurs mesures. As-tu un multimètre? À partir de 1:19 il y a des schématiques, on peut travailler avec ça.
+Curt Heisler same thing happened to me. mine happened withing the 12 months, and when i wrote to them they screwed around with me long enough to pass the 12 months, then said it was no longer their problem.
+Jordan Rooney with enough spare time, you could pursue some kind of settlement, but all concerned know the new rca TVs are a bunch of shit. Any responsible engineer would be embarrasesd to have their name attached to such an ill-conceived contraption.
how can i check all that i have a volt meter? is it possible that could be the only thing? i get noting no power! i can send a pic of the board looks the same has same burn spot
+James Bond Go to 3:00, there is a schematic. Power on TV. Check voltages on the cathodes of the diodes. If there is nothing anywhere then there might also be a problem on the primary side.
thanks sir by u video, it is very explicit information, by i need to find a new coil or toroid, where i could buy one by unit or at less no more than 5 units , in that value that u calculated, 30 to 50 uhenrios.. i have the same problem in this kind of TV, but to fixed this i changed he mofet transistor ME15n10-g how u explained, but the coil was very hot when at putted all covers the TV turned off again, i think that the coil is not was the right, what u recommend me to fix this power supply board correctly. thanks Sir you are very experimented man.. thanks again.. have a good future in u life ,, Albert
It seems to me the inductance doesn't support the current the circuit was adjusted to in the long term. It overheats and damages the core. I didn't understand if you tried to reuse the core. You cannot. The tiny particles powdered iron cores are made of are not isolated anymore after the core overheats. Therefore when trying to reuse it it will overheat again due to excessive eddy currents. You need a new core. You can get them from ebay for example, depends on where you live of course. I am not a specialist in all the different core materials available but you could try it with something like this: www.ebay.ca/itm/Toroid-Core-Inductor-Wire-Wind-Wound-150uH-42mOhm-5A-Coil-/321201780611?pt=LH_DefaultDomain_0&hash=item4ac91e3783. Other than that I recommend using an oscilloscope to make sure it does not saturate and lower the LED current a bit.
I have a Proscan PLDED3273A-E. Looks exactly like by problem (brown spot on board) but I think this is way over my head - I need to find me a local fix-it guy - Thanks anyway :-)
yves raymond Est-ce que le rétroéclairage fonctionne toujours? Si vous ouvrez la télé vous pouvez le voir par des petits trous dans le panneau LCD. Vous allez trouver le schématique dans le video. Faut vérifier s'il y a toujours du voltage aux bornes des DEL. Cela va vous prendre un multimètre. Pas de rétroéclairage signifie que soit le rétroéclairage est défectueux ou que le circuit que commande le rétroéclairage est défectueux... Dificile de dire d'ici. Si vous parlez anglais je peux recommander le forum sur badcaps.com.
Great video, excellent analysis and reverse engineering of the circuit. You did all the hard work for me, all I had to do was select an appropriate inductor from my junk box and solder it in. Thank-you!
I have one of these as well, replaced the ic, mosfet, coil, and took your advice on replacing those sm resistors. I tired (2) 1/4 watt 5.6 ohm in parallel, but couldn't get the temp any lower than 190 F. I clipped one of the 5.6 ohm off and just went with one. Got the temp down to 130 F on the coil. I think this is as good as it gets. I think 1/4 watt is fine. Thanks for the video. It helped a lot.
I was in the same situation with a burned out L1 coil. I had assumed it was the caps and replaced them. When this didn't work I was about to give up hope. Thanks for this
You're welcome. I guess we all repair this way, check for the obvious first, caps, solder joints etc. I also wanted to give up but when I got 2 of them I thought it might be worth it.
Thanks for the help! Nice diagram, had the same issue. Burned out the Mosfet, the PWM chip was fine though. Replaced the inductor with one from a PC power supply but was getting only 40 volts out on the LED lead and it was heating to over 130 degrees! Hooked up the old inductor to my ebay build your own component tester and got .30uH the power supply inductor was only .07uH. I grabbed some inductor wire from the local electronics store and wrapped about 5 feet of it around the new PS inductor after removing the wire and tested it and got .17uH. This gave me 69 volts and then proceeded to remove the 1.2ohm resistor and added a 33 ohm resister ( with the 3.0ohm) for a 2.8 ohm final value. It works great, coil reaches 65 degrees but the insulation is rated for about 120c so should be good. Thanks!
Good it works. Do you mean you put a resistor in parallel with the 3R resistor? That would actually increase the LED current and they may become damaged more easily over time. I'd recommend to increase the overall resistance, in my case I about doubled it. (from 1.2||3 to 3.3||3.3)
Thanks for the reply! I did remove the 1.2ohm and put a 33 ohm in parallel. I figured that the resistance would be the same as adding 5.6ohm x 2 in parallel = 2.8 ohms. The 1.2II3.0 combo was 0.8 ohms. To duplicate the 2.8 ohms I took out the 1.2 and added the 33 ohm with the 3 ohm. It came to 2.8 as well. I thought using ohms law, the current would be the same but most of it would pass through the 3 ohm smd resistor but it can handle it at that current. I(t)=(I=V/R1) + (I=V/R2). I'm new to this and am trying to figure this stuff out. Let me know if I'm wrong? I also replaced the main filter cap as the ESR was high. Thanks again.
Ah ok, I didn't catch that you removed the 1R2 resistor. That's ok then. The only thing to observe would be power dissipation of these resistors, most of the current now goes through the 3R. Can't remember the average current though but I think it was pretty low... Shouldn't cause a problem. Cheers
Thank you Tom,just repaired one thanks to your video.I was just about to give up on it.
Glad I could help
that was fantastic! Entire video was informative, to the point, fat free and absolutely digestive. will follow up with details after attempting your suggested mods.
found a toroidal on a junked circuit board. a little larger but with about the same number of turns, maybe larger wire. looks like it was a filter for an audio output , possibly digital amp. also removed the point three ohm smd resistor from the other parallel one ohm ones, to decrease led current. end result, 31 volts in, 60 volts produced at led feed. Backlighting adequate, and coil and other parts running cool....
Nice, hope it will hold up
Heh,I knew I was saving all those pc power supplies for something.The heat melted the solder and opened the circuit.I temporarily put the coil back in.It lit ok,but the coil heated up.The board is a bit scorched,but seems ok.Nice video.
Thanks to your help now I have TV.
Thanks for replying to my post you the best man now I see and understand the differant parts of the video and not just a whole bunch of jabber lol
I didn't measure the inductance of the replacement inductor. However, current rises to 1.6A in 2us. I think I remember the boost circuit input voltage to be around 30V. Therefore the calculated inductance is 37.5uH. I think anything between 30uH and 50uH will work just fine. It needs to have the right current rating of course.
Me Tom it's me again on my way to buy the condutor which do you say is best don't wanna get to radio shack and be looking stupid please and thank you because those assholes might not know they just work there salesman it a hot chick usually so
James Bond Say you want a toroid inductor with a powdered iron core, inductance anything between 30 to 150uH good for 3 to 5 Amps. Still possible they won't know what you are talking about. Say you do not want a ferrite core. The ones I tested were all saturating.
+James Bond good luck. radio shack is not the fun it used to be, but sounds like worth the visit. look for a similar looking coil on junked boards.
great video! (but why the music in the background?)
Because I like music ! :-)
Got a RLDEDV3255-A , now after 3 years.... Same problem...
merci, pour ta réponse oui le ic est le led driver et semble très difficile à trouver et la carte est plutôt dispendieuse compte tenu du prix de la télé . Au fait excellent travail ton video
ouais, en plus je recommande pas d'acheter ces boards,, j'ai pas eu des bonnes experiences...
Hey there. I tried your fix for this tv. Same board issues except the other two components burned out on your board aren't on my board. I used what you suggested, one from a PC pwr supply but way larger. This one has four leads in the board. I used only two of them but still no change in the tv. There is power at both leads of the replacement but still the tv stays off.
I have pics of the repair I did but don't know how to get them to you to view.
Where else might there be damage not visible?
you should be able to send me an email to tomtechtod (gmail).
you seem to have a different board though, you say you don't have the transistor or controller chip?
the four-legged inductor you used may be a common mode choke, don't know if this could work.
Hi, I am in the process of the repair and completely forgot to locate the orientation of the OB3350CP POWER PWM CONTROLLER. Can you please tell me where the dot is facing on the board, with the straight edge of the board facing up. I appreciate it very much.
+PHIL GIBSON Click on the "fullscreen" button of the youtube video, then on the little gear (that's the settings button). Adjust the resolution to 1080 (high definition). Go forward to 1:16 in the video, there is a picture , the controller chip is circled red and you can clearly see the direction it needs to be mounted.
Awesome video. got a new coil. changed resisters to two 5.6ohm like you did.
when i give it power i hear a clicking sound and that's it(no power light of any kind). could this be the mosfet or controller you talked about that has gone too? they do not look burnt but its hard to tell.or its just something different all together.
Thanks.
SegaMan001 repeatedly clicking or just once? To check the MOSFET measure its bodydiode from source to drain and gate to source resistance. What about the voltages? Do you have 12V? Does the primary controller work? Do you have a scope?
TomTechTod I do not have a scope. been meaning to get one. the clicking is every second.
i am getting 1.3ohm on D to S and 3.5ohm on G to S. have not done much MOSFET testing before. when live the voltage over the MOSFET jumps from nothing to higher numbers every time it clicks. I will play with the primary controller and see what i can find. I may need to read into this some more. thanks
SegaMan001 1.3Ohm between source and drain means it's shorted/defective. My guess is the primary side tries to startup and sees a short on the output, hence stops and then restarts.
The secondary boost controller may also be defective.
I would first remove the FET and measure it again, then measure if there is a short form the controller output to secondary ground. If there isn't you may be lucky and it's just the FET. If you have any spare FET with over 100V VDSmax and a few amps IDS max give it a try before buying the original one.
hi in need for a AYN5YA ic for a cv3393bh-p32 model plded 3280 in Canada Qc , you know where to find it ? thx
Ça semble être le driver pour les DEL. J'en ai eu des cartes avec ce même chip sauté et j'en ai pas trouvé pour l'acheter. La seule manière d'après moi c'est trouver un IC pareil sur un autre board semblable ou acheter un board de remplacement. Trouver un board qui est exactement pareil (sur ebay par exemple) est quasiment impossible parce qu'il y a beaucoup de variations de cette carte, il peut même y avoir de cartes differentes dans le même modèle de télé... Pour une Proscan 32 pouces ça vaut pas la peine d'après moi.
I have a Proscan PLDED3273A-E with the same problem. If I only replace the inductor with one like the "Toroid Core Inductor Wire Wind Wound 150uH 42mOhm 5A Coil" will that be enough to fix the problem? Or do I also have to replace the resistors?
Chris K You can try it. Someone told me after some time the new inductor heated up also though, I would recommend to lower the LED current...
Ok, I'll replace both parts to be safe. Thanks for your informative video and input.
So I should buy 2 resistors with a 5.6 ohm resistance? Is there other specs they need to have?
I'd use 1/4W resistors. Or just one 2.7R resistor with 1/2W or more.
When connecting the resistors or inductor does it matter which way I solder the parts to the board? Do the parts have a negative and positive end?
Hi Tom, first, just want to say thank you for the great effort in making this video. Nice and crispy and straight to the point. second, I have the proscan PLDED3273A-E TV which had the exact problem of inductor coil burnt out completely. I have no problem of fixing the coil but I would like to seek your confirmation or advice on the parallel resistors to be soldered on top of the 1R20 and 3R00 resistors.
As the space on the PCB is kind of limited..is it correct that both 2.8 Ohms resistors are to be soldered together ie one leg of the 2.8 Ohms resistor is to be soldered to 1R20 resistor leg and the other leg of 2.8 Ohms resistor is to be soldered to the joint next to 3R00 resistor...Sorry that I am ametuer on this kind of DIY electronics stuff. Thanks a lot in advance for your advice.
Hi. I removed the SMD resistors and soldered the other two instead. Same location, just a higher resistor value. You have to remove the original resistors otherwise the LED current will even increase if you add anything in parallel to them.
+TomTechTod great stuff and it is very much appreciated Sir. I shall stick with your original advice using 2 x 3.3 Ohms resistor to replace the original 1R20 and 3R00 resistor. Thank you very much for your kind support and will update on the progress when I receive the coil...ebay shipment from HongKong.
What is the spec for the original inductor coil, where can I order a same replacement part?
{all measurements are approximate} toroid: D exterior=15.22mm, d interior=8.3mm, h=5.95mm (iron core??); (burned) wire: 0.53mm (5ft length) and 71 turns =>10.5mH (iron core k=200)
can you show a better picture of the resisters you installed thank you
No, sorry, I repaired this TV in 2015.
Thank you for the great video. I did exactly what shown on your video, got it to power on with sound and the PROSCAN blue screen logo shows for a second. All functions are working, but the screen is dark. You can see what is on the screen in a dark room only. Please help me understand what I did wrong.
+Allan Aoukaty What is the DC voltage from cathode of D17 to ground and from anode of D18 to ground while the TV is on? If you have a scope: What's the signal on the gate of the FET?
Bruh ion know nothing bout this but RCA red light is on but It wont come on plus the power button is broken........... but it would definitely come on im just trying to figure out how........ do I gotta get a new broad ?
have a nice time sir! I just wanna ask if the PROSCAN 32"MODEL PLDED3237-G can plug it to 220v directly? The indicated power supply at the back is 100v-120v only. But the design in the power supply is like autovolt.The Filter capacitor is 400v/100uf. Pls consider my question.tnx in advance sir.
If it says 120V I would not plug it into 220V. Usually, if it supports 220V it would say so on the label...
Great video! I have one of these hanging around with a fried (literally!) toroid for a while because I couldn't find any documentation showing the toroid value, and also didn't know that this problem could involve other parts of the board as you described. Did you say we can use a toroid inductor from any desktop power supply? Is there any way I could test the LED current controller and the MOSFET before replacing them? They are visually perfect and intact with none of those common signs of discoloration due to high temperatures as shown in your board (don't know if you damaged them after replacing the toroid inductor without making the modifications described). Anyway.... Thanks for the great tutorial! That certainly helped a whole bunch of folks including myself.
By the way my board looks identical to yours but comes from a Proscan PLDED3273A-E 32 inch tv.
Thanks. I damaged MOSFET and controller after rewinding the old toroid core. It's an N-channel MOSFET. Simplest way is to do a diode test from source to drain (right pin to middle tab) , it should show the voltage drop of the body diode. Also test if there is a short from gate to source. My controller shorted out the power supply after I damaged it. It doesn't happen immediately so you could try to replace the coil first.
The circuit is quite forgiving in terms of different inductance values and saturation levels. I would still try to use a core which is bigger in diameter so it can dissipate more and one that doesn't saturate like the first one I showed. There are so many ferromagnetic and ferrimagnetic core materials available it would be quite a challenge to find out what exactly is the best to use. As I said I prefered a straight current slope, a reasonable duty cycle (not too big, not too small) and relatively small peak currents.
Rodrigo Santos Good to know I'm gonna put it in the description.
Rodrigo Santos Vc por acaso é brasileiro? Essa TV foi vendida no Brasil?
TomTechTod Sou brasileiro sim! Você tambem é? Essa televisão foi comprada aqui em NY por um amigo meu que me pediu pra dar uma olhada depois que ela parou de funcionar. Meu conhecimento em eletrônica é muito basico mas as explicações dadas no seu tutorial simplificaram o problema consideravelmente. Vou ver se uso um indutor que vou tirar de um power supply de um PC que não uso mais e ver no que dá. Mais uma vez valeu a força! :)
I replaced the inductor coil with a slightly smaller one that I took off a working power supply from a different unit that had a broken screen. Some of the traces leading up to that actually got separated from the PCB a bit, but I continuity tested it after and it was a solid connection all the way through, so i'm assuming that wouldn't be the problem. Anyway, my problem before replacing the inductor was that the backlight wouldn't turn on. The weird thing is that I actually took the old broken coil out and the display would still turn on just fine, just with no light. Is the circuit that the inductor runs on only powering the backlight? Now that I replaced the coil i'm just getting a clicking every second or so, without a standby light or anything, so i'll just have to trace up to the point it would put that out probably.
Another question,
If I were to just take a secondary external power supply and hardwire it to the backlight, would there be any problems with that? This TV is honestly only going to be used in the back of a computer repair store, so it definitely doesn't need to be a practical or nice looking fix :p
+mookiedamouse2
1. the part of the circuit with the inductor in it is a booster for the LEDs (with current feedback) , so yes the rest of the TV could work without backlight
2. you need a current limiting power supply to power the LEDs, you could probably take one or two benchtop power supplies and put them in series and drive the LEDs with it. It should be in current limiting mode though.
Since after your repair attempt it doesn't do anything anymore you need to find out first what's preventing it from turning on. Maybe the driver IC and/or FET is shorted, when you put in the inductor the primary side shuts off due to overcurrent . What happens if you remove the inductor and try to turn it on again?
+TomTechTod
After I took the inductor out, the TV would turn on again.
I took the inductor out of a few different power supplies and now know that the backlight circuit is the only thing wrong with them, but I don't have the tools in order to figure out what sort of new one to put in there, and how to actually get more of them, or know what they're rated at.
I have one of the units put back together (without the inductor), and got the backlight wire to hang outside of the TV. I have quite a few CCFL power inverters here that were used for lighting in desktop towers, so they're powered from a 4-pin molex source. I don't actually know what the inverters are putting out, but I have 12v, 2a going in to it. Wired it all up and soldered the connector for the backlight wire to the end of the external power supply-thing I wired togeter, and surprisingly, it actually works! The backlight does definitely come on, but it's pretty weak. I have an extremely cheap volt meter (which I don't entirely know how to use), and it seems like it's putting out 8 volts, with an unknown amperage. We have a benchtop power supply that has 3 outputs. One of them is fixed (to something I know would be way too much), but the other two are variable output sources, ranging from 0-24v, and up to 600mA. Would any combination of that wind up being enough? Once I find out the magic stats in order to get the thing to light up properly, I can figure out what I need to do to make a few supplies to put that power out and get it all wired inside of the TV so it turns on with the rest of the unit just fine, i'm just lost when it comes to volts/amps/ohms/watts and any other sort of magical electrical terms that I like to pretend I understand.
Thanks for the help!
+mookiedamouse2
1. Apparently the secondary MOSFET is shorted and therefore with the inductor in the circuit you are overloading the power suply.
2. A CCFL inverter output has way too much voltage, you probably didn't burn your LEDs because it cannot provide enough current to do so.
3. With 2 x 24V supplies in series you only get 48V. I think the voltage drop over the LEDs was about 70V so you would need an additional 24V power supply and put those 3 in series. MAKE SURE THERE IS A CURRENT LIMIT on those power supplies. LEDs are current driven devices. That means you would connect the 3 supplies in series and turn down the current limit to zero to begin with. Then increase slowly the current limit until the desired brightness is achieved.
Don't make it too bright, this will increase the LEDs life expectancy.
Hello from Dave, I have the same tv, but I don't see any damage on the board, but the red light turns to blue when I turn it on.but again there is no sound and no picture.could there be a fuse that could be gone, and if so where would I look for this fuse. thank you for your time. Dave Mack
+Dave Mack I don't think it's a fuse. Please refer to the schematic contained in the video. You should be able to find the fault if you have a multimeter to take some voltage measurements.
One last the new board don't turn the tv on at all but the old board does.
If the new board is physically EXACTLY the same I would try to swap the memory chip from the old board to the new board, normally an SOIC8 near the microcontroller.
Or you could repair the old board.
i did repair that set but i have the plded 3273A no back light ...what component cause that
+Daddy Roots Do you have the same boards? These TVs may use different boards even though the TV model is the same.
I got a proscan PLDED5066-E POWER TURNS blue when on screen shows brand name then it goes blank is it the power supply
It's likely the PSU, yes. Could also be a shorted LED somewhere and the PSU detects this condition. Hard to say. These TVs are hardly worth the trouble witheir crappy mainboards...
Hi, I work in I.T. but one of my customer's brought his Tv such as the one you're working on and it doesn't turn on. Red light is on but nothing...he claims sometimes it does go "On", but not always. I took it apart but nothing looks off on the power supply, nothing burned..any suggestions?
could be a bad contact on one of the leds or bad solder joints on the pcb. hard to say ...
Do you think swapping the power supply would fix the problem or it could be another component?
+NextGenHye yes, it could be one of the LEDs
I moved around the connector that goes into the power supply on one end and to the power cord on the other and tv turned on..i played around with it some more and it stopped turning on..i'm gonna redo some of the solder..usually i put motherboards with bad soldering into the oven for 10 minutes lol but looks like there are lots of plastic parts on the power supply which might melt..so i won't lol
Well redoing the solders didn't work :( are there capacitors i can test perhaps?
I'm giving your video a thumbs up but my problem still persists i have almost the same model proscan i stripped it down to the LCD lights to see if that was the problem it was not the problem they all worked after putting it back together i put the old video board back on and it turned on but the picture lighting was to low on that board then i decided to replace the video board. Following the instructions to reset the board you have to plug it up and wait 5 to 10 minutes before hitting the power button it did not turn on i then switched back to the old board and got the same thing comes on but not enough voltage for the picture to show i just want to use the new board since everything is refurbished but it don't have enough voltage to even turn on the tv like the old board any suggestions?😐😐😐
"Almost the same model" sounds like trouble. I never had luck buying a replacement board for these TVs.
Me to because i went through 4 just sending them back thinking that it was a manufacturer error but when you said change the swap the memory chip it dawned on me that could be the problem because when i plug it up the power light comes on but the tv don't fire up. I didn't switch it just yet but when i get time I'll let you know the outcome. Thanks in advance
i have a bunch of thees tv i rewind a few and it works now i have to go back and do the adjustments
"a bunch" sounds good because then you will have "a bunch" of working ones. Just lowering the LED current a bit will be ok. After watching it a while I found I maybe lowered it too much. I guess 2x3R3 or 2x4R7 in parallel may be better.
btw just rewinding using the old core didn't work in my case, had to use a new / salvaged core.
TomTechTod Hi Tom, I watched your youtube video regarding the RLDED3258A RCA LCD. Your end remark mentioned 2x3R3 or 2x4R7 in parallel may be better. Does this mean that the 2x5.6R in parallel are not necessary? That these lower values of resistors in parallel are fine? BTW: Great video and thanks for caring.
Paul Taylor.
Originally there were 1.2 and 3 Ohms in parallel. I tested several higher values and found that with 2.8 Ohm the picture was bright enough. You can put in higher or lower values, depends on your preference (brightness). The higher the LED current the more the stress will be on the switching components and LEDs.
Après toutes les étapes, la télévision n'a aucun courant.. la lumière rouge a l'avant elle est fermée et lorsque j'appuie sur Power, aucune réaction. La seul chose c'est que la télévisions fait un petit "clic" a chaque 2 secondes environ et sa me vien pas des haut parleur mais plutôt la carte mère. svp si qqun pourrait m'aider. merci
+Nathan Mayer (NeeZiaa) As-tu remplacé le transistor et CI driver et la bobine comme décrit? Il faudra que tu prenne plusieurs mesures. As-tu un multimètre? À partir de 1:19 il y a des schématiques, on peut travailler avec ça.
quel modèle ?
I have this T.V, and on the 13th month, (1 month after warranty expired) the EXACT same thing happened! How is that legal?
+Curt Heisler same thing happened to me. mine happened withing the 12 months, and when i wrote to them they screwed around with me long enough to pass the 12 months, then said it was no longer their problem.
+Jordan Rooney with enough spare time, you could pursue some kind of settlement, but all concerned know the new rca TVs are a bunch of shit. Any responsible engineer would be embarrasesd to have their name attached to such an ill-conceived contraption.
same here but the chinese don't care RCA is no longer American there junk
hey tod monster im ready to order that coil inductor can this fix my tv it doesnt power up no red light noting no clicking but it burnt like yours
+James Bond *tom
James Bond there is probably other defective parts too, check MOSFET and 12V etc
how can i check all that i have a volt meter? is it possible that could be the only thing? i get noting no power! i can send a pic of the board looks the same has same burn spot
+James Bond Go to 3:00, there is a schematic. Power on TV. Check voltages on the cathodes of the diodes. If there is nothing anywhere then there might also be a problem on the primary side.
thanks sir by u video, it is very explicit information, by i need to find a new coil or toroid, where i could buy one by unit or at less no more than 5 units , in that value that u calculated, 30 to 50 uhenrios.. i have the same problem in this kind of TV, but to fixed this i changed he mofet transistor ME15n10-g how u explained, but the coil was very hot when at putted all covers the TV turned off again, i think that the coil is not was the right, what u recommend me to fix this power supply board correctly.
thanks Sir you are very experimented man.. thanks again.. have a good future in u life ,,
Albert
It seems to me the inductance doesn't support the current the circuit was adjusted to in the long term. It overheats and damages the core. I didn't understand if you tried to reuse the core. You cannot. The tiny particles powdered iron cores are made of are not isolated anymore after the core overheats. Therefore when trying to reuse it it will overheat again due to excessive eddy currents.
You need a new core. You can get them from ebay for example, depends on where you live of course. I am not a specialist in all the different core materials available but you could try it with something like this: www.ebay.ca/itm/Toroid-Core-Inductor-Wire-Wind-Wound-150uH-42mOhm-5A-Coil-/321201780611?pt=LH_DefaultDomain_0&hash=item4ac91e3783. Other than that I recommend using an oscilloscope to make sure it does not saturate and lower the LED current a bit.
I have a Proscan PLDED3273A-E. Looks exactly like by problem (brown spot on board) but I think this is way over my head - I need to find me a local fix-it guy - Thanks anyway :-)
I hope you find one. Good luck.
que faire j ais plus d image mais j ais toujours le son ....
yves raymond Est-ce que le rétroéclairage fonctionne toujours? Si vous ouvrez la télé vous pouvez le voir par des petits trous dans le panneau LCD. Vous allez trouver le schématique dans le video. Faut vérifier s'il y a toujours du voltage aux bornes des DEL. Cela va vous prendre un multimètre. Pas de rétroéclairage signifie que soit le rétroéclairage est défectueux ou que le circuit que commande le rétroéclairage est défectueux... Dificile de dire d'ici. Si vous parlez anglais je peux recommander le forum sur badcaps.com.
Ahhh, my fired coil had in the label this data L101 i think that is 100uH..
What is the spec for a same replacement part of the inductor coil and where can I order it?
thanks but i wish to get your number to learn from you am in Jamaica
Hi do you have an email address? I have a question with a picture. thank you
+Tony Newson You should be able to contact me via Google+. I also recommend the forum on www.badcaps.net/forum/index.php
th-cam.com/video/GrfSmtzFjCc/w-d-xo.html