So i am repairing a 60 inch lg tv and ran into a problem. There is power board with surface mount diodes but i am not able to make out the number and they are giving me a 0 read so i am trying to replace them. How do i go about finding what model diodes i need or is there a common surface mount diode that i should order for a tv. Thanks.

 

Perhaps you can provide the Mfg. and Model #, there are a lot of suppliers.

It would help if you could get a schematic also, but I've had difficulty getting those.

HTH
Gary

 

it is an 60 inch lg model number 60pv250 and the board number is ebr73561701 . i havent had luck finding a schematic . found a couple sites where they sell it and was wondering maybe that is the only way to get schematic is to pay for them?

 

Sometimes a clear photograph of the part and surrounding circuitry can be enough to guess a replacement.

 

What's wrong with the TV is a good place to start a thread and posting up pics always helps out too..

 

sorry for the late reply. My phone was stolen so couldnt take pictures. But anyways the model tv is 60pv250 LG. The board number is eax64232101 but does have a sticker also saying ebr73561701 so not sure what go go by. So the tv has sound but no video which was the reason that i bought the repair kit from ebay which said it fixed that issue. the repair kit involved a fuse and 6 fgpf4633 field effect transistors and 9 surface resistors. I received the transistors yesterday and soldered them on and happy thinking it would fix it but it instantly sparked when i connected it and using a multi-meter i saw that 3 of the transistors i installed were shorted.It was a pretty violent spark that came from those 3 transistors. Any clues as what might have caused it? And should i desolder the two heatsinks so you can better get a look at the transistor?

 

sorry forgot to mention that that i added a picture of the instructions or the diagram of the repair kit of the parts that were replaced. what could have caused that violent reaction of the transistors that blew up. on the diagram they are the ones on the right that blue up . if i need to zoom in picture or anything to help figure the issue just let me know. I am new to the site so not sure exactly how to present this .

 

What lead you to this repair? Can you post a good picture of the back of the Tv set? Have you checked power supply voltages and tried disconnecting the y-sus board and the Z-sus board one at a time to see if you have any picture? When you turn this on in a dark room, is there any backlight or glow?
Before you do any of this, I will caution you that there are parts of this TV that will feed you a lethal dose of electrons if you are not careful. If you are not familiar with TV repair, I strongly caution you on attempting any repairs and recommend you seek a professional.

 

Well the main power board has all the correct voltages going out to the y-sus board and z-sus board but the tv turns off when the board i attempted to fix is connected to it. and it is not producing the voltage out to turn on the backlight so that is when came to that repair kit . when that board which i am not sure how to tell it apart whether the y sus board or the z sus board is no connected the tv stays on but only has sound and that repair kit described those symptoms for that board. I just wnat to learn how to properly dignoste all of it because for me it is a learning experience . I have fixed a few tvs already that there was simple problems like blown fuses or bad diodes or bad caps but if it is none of those then i can only find which board is wrong and just come to a dead end. I will post a picture of the tv when i get home. Any help is greatly appreciated

 

When you are standing at the back of the TV, was the board on the left side (Y-sus) or on the right side (X/Z sus)? What were the exact voltages you measured from your power supply and what were the voltage specifications for the same. On the TV, there is usually a white tag that tells you what Vg/Vs should be. What did you have? Again, I caution you if you are not familiar with this work because there are parts of that TV that run in excess of 380VDC.
Which of the boards shuts down the TV picture?

 

X/y sus which is the board on the right . And when it is connected it just makes the TV click and keep turning off when it is not connected the TV plays but only has sound and no picture . I will post exact voltages when I get home .

 

Look for sticker on back of set with voltage specs and post those as well. Check for VSCAN on left board (Y-SUS) and Ve on right board (X-SUS). Sounds like X-SUS board may be bad. X-Buffer would also be a recommended replacement if that is the case.
Anybody else have any thoughts?

 

ok so x-sus readings are 5v--> 5v , Va--> 55.5 , gnd--->0 , gnd--->, vs--->201, vs--->201 , and readings for y-sus are 5v---> 5v, Va--->55.3 , Gnd--->0. gnd--->0 , vs--->200, vs--->200 so the readings seem to show well as long as the x-sus is not connected because the volts seems to go to 0 except the 5v which i assume is the standby .

 

And bwilliams or anyone can i get a break down on what goes bad most of the time on the sus boards. I dont think this tv fixed right away and i want to go beyond board swapping to fix tvs. i have fixed a few tvs in the past but only by board swapping and i really have a passion to fix things so i want to learn component replacing and in my school i really am not doing much for hands on electronics which is agitating.

 

Several thoughts here for you:
1) When you soldered all your new components in, were they direct replacements for what was taken out? Exact part numbers, shape, size, specs etc?
2) This does sound like the X-SUS board (right side) is shorted but could also involve the x-buffer and even the display unit
3) To learn about testing components, there is a very good website:
www.talkingelectronics.com/projects/Testing%20Electronic%20Components/TestingComponents.html
4) For good e-books on electronic repair, go to Jestine Yongs website. There are several books on there to help you.
5) If you can get a really good shot of the front and rear of the affected board, perhaps we can help you with the diagnosis. Often times the IPM module will be the failure point on the board
6) You need a decent DVOM, an ESR meter such as the Blue ESR meter from Anatek and an oscilloscope would be helpful
7) Lastly, do you know how to find and read datasheets for components?

 

i have a question bwilliams60. i have decided to go ahead a replace everything on the heat sinks.But want to make sure im testing this out right . on the superfast acting diodes in the t0 220 casing part. rf2001 and i testing the cathode part as the middle pin and the left and right as the anode because one or two just beep on the continuity test. was reading it is advice to replace all if one of those go bad so gonna go ahead and do it. As far as

 

Cathode is middle pin and anode on the outer pins. If you have a DVOM, use the diode function as it will be the most accurate.

 

ahhh k just making sure but two are bad then guess i have to wait for the parts to come in then ill see what else comes up. Any equipment that i must have bwilliams60 for most tv repairs? i have the basics like dvom, just got an esr meter , solder iron, getting a dc power supply when i save up a bit more or would a variac with isolated transformer suffice? i know one produces dc voltage while the variac produces ac but in a book i was reading the guy was using a dc power supply to slowly raise the voltage to a power supply untill the current got to 2 amps in order to feel which componet got hot in order to quickly find a short so was wondering woudl i get the same effect with a variac?

 

Everybody has their own techniques. An isolation transformer is a must. An oscilloscope would be helpful. Sounds like you are on your way. Grab some reading material, perhaps the stuff I sent you, and then maybe some others, and you're on your way. Stay on this post though and let us know how you make out. Please be careful. Show pictures if you can. Helps everybody else understand what you are doing.

 

I will skip an oscilloscope for now because they seem quite expensive . but is a dc power supply like the 30 dc with 5 amp really needed if i decide to get a variac with an isolated transformer?