not sure what to make of this. Appreciate any pointer
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Re: Troubleshooting AC/DC circuit board
not sure what to make of this. Appreciate any pointer -
Re: Troubleshooting AC/DC circuit board
Clean off the black carbon with IPA first and look at the pin really well, it looks like it has cold solder joint on that transformer pin.Leave a comment:
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Re: Troubleshooting AC/DC circuit board
In the process of testing and out the output from various capacitor, spark fly and this happen. See pic
The blow lead belong to the transformer...the big block module sitting in the middle of the board.
Does this mean it's bye bye? Or can I just resolder it? How do I test transformer.Attached FilesLeave a comment:
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Re: Troubleshooting AC/DC circuit board
Old gun had over 20 yrs now. Can't tell what wattage anymore because the label is all washed out. Chances are it's not lead free and the board probably use lead free which require more heat/new gun.
I'm also using the wire mesh/braid to remove the solder.
Will look into new soldering gun. Anyone to recommend? Seen Weller on Amazon but they are a bit $$$.Leave a comment:
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Re: Troubleshooting AC/DC circuit board
What is the wattage of this soldering iron? Tips size? The trick is to add more solder and flux to the joint first.
What tools do you have for removing the melted solder?
You should practice on scrap board so you will not damage then board you are trying to fix.Last edited by budm; 03-29-2015, 12:59 AM.Leave a comment:
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Re: Troubleshooting AC/DC circuit board
Well, I hope it's ok to continue this thread on different topic/question.
I'm trying to remove the cap from the board. My soldering gun can't seem to melt the old solder. But it can melt new rosin-core. Does this mean I need a new gun with more power just to melt the old lead on the board?Last edited by soyuppy; 03-29-2015, 12:55 AM.Leave a comment:
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Re: Troubleshooting AC/DC circuit board
You can use hot glue or electronic grade Silicone RTV not typical Silicone RTV which is corrosive.Leave a comment:
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Re: Troubleshooting AC/DC circuit board
thanks for the advice. Will look for Pan FR series from either Amazon, DigiKey or Mouser.
Probably will replace all the caps, including one in the primary as suggest by @stj. But in doing so, I will need to remove and reseal the white caulking material as well?
What is this material call?Leave a comment:
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Re: Troubleshooting AC/DC circuit board
panasonic FR series preferably, whatever ou use - no 85' temperature junk.Leave a comment:
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Re: Troubleshooting AC/DC circuit board
OK, so we get to see to top side of the power supply board, I can see at least 3 bad caps with bulging top, I would replace all 4 in the secondary side.Leave a comment:
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Re: Troubleshooting AC/DC circuit board
more pic of top and bottom as requested
159.99VDC is measure on the capacitorAttached FilesLeave a comment:
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Re: Troubleshooting AC/DC circuit board
OK, you will be making Voltage measurement in the hot deadly side of the circuit so you MUST BE REAL CAREFUL.
We need better straight shot pictures of the whole top side and the bottom side of the board so I can locate the main AC fuse.
Right now we do not know if the SMPS circuit is getting the DCV to run or not, so you should check and see if you have 160VDC on the two legs of the main filter cap (big brown cap laying on the side with yellow tap on it) first. If there is no voltage there then we need to check the main fuse and the bridge rectifier.Last edited by budm; 03-28-2015, 10:41 AM.Leave a comment:
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Re: Troubleshooting AC/DC circuit board
relpace the 47uf startup cap
use something semi-decent like a panasonic FR series.Leave a comment:
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Troubleshooting AC/DC circuit board
Not sure if this is the right forum. It's it relating to AC/DC circuitry. Figure its in the same domain as PSU.
I have fault AC/AC circuit board. 2 different DC voltage are output. One is 3.3V and another is 14.8V.
Upon inspection, nothing looks burned and caps look clean. Doesn't look like there's any faulty component.
Understand typically there's fuse, but can't seem to find the fuse box either. I have confirmed output from the AC housing prior to entry onto the IC is in tact with ~120VAC.
Where would I start to diagnose this board? Is there a way to test if transformer?Attached Files -
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All left and right refers to looking from rear of TV (or looking from front with TV upside down)- TV came with vertical bars and no image. Found faulty TVS on left buffer board. Also replaced T-Con (may have damaged the original while hot air removing components, board has slight warp) and have full image but few horizontal lines on the screen. Some of the lines appears to be 2 pixel tall while others are 1 pixel tall.
- Disconnecting left and right buffer board potentially reveals problems on both sides with different signals (unless this T-Con require jumper like Samsung FB_TRDY1&3) Fault
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This is my first attempt at troubleshooting a board like this, I know I could just buy a new board but I'm curious to figure out how this works. I've been testing different components in the evenings this week and I think the problem is with the IC failing to start up for some reason. When the board is plugged in there is no standby voltage.
Then today it randomly sprung to life like a zombie but shortly died thereafter. I have no idea why it would have done that and its the first time I've seen it running. I discharged capacitors on the board last night, then it was sitting today.... -
I was Ollie today which is a close out / surplus outlet store I do not go in there to often because you find things that you should not be tempted by but that is a another story
I saw a small space heater that used a wire type of heater element which I been looking for a while but not really hard mind you but when I saw this I grabbed it I going to go back tomorrow and buy the last one that is like the one I bought today because I need the heater element and the ceramic insulators and more of heat element wire because this one has two different wattage settings one 1300 watts ( tap... -
This board attaches to 2 12v batteries in tandum (Black/Red squares). There is a 24v power supply that attaches at the 2 pin molex connector (circled in red). I need help to determine which components run the charging circuit in an effort to determine a point of failure. There are multiple via's, making it difficult to trace the circuit. Nothing appears to be shorted but I wasn't able to fully test as I do not have 2 12v batteries available. My assumption is that the micro controller (red question mark) determines when to turn the charging circuit on & off. I'm pretty sure a regulator and...
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Hi, this is my personal laptop, which the original board (lets call it Board A) blew up PU8700 (TPS51486), making a hole on the board, i had left the laptop at my desk one day with the battery fully charged and didn't touch it for a week, but when i tried to turn it on it didn't
Thought the battery was dead, so i plugged in the charger then tried to power on, the power LED blinked once, charged LED still orange, unplugged the charger, plugged in again and I noticed the "magic smoke" smell, so i unplugged the charger, removed the back cover and saw the blown IC (the "magic...
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