I have a tv power board that had a few bad components on it that I replaced but still wouldn't power up so doing more checking, I found a 4.7 ohm resistor(fuse?) that was open. My question, does anyone know if a regular 4.7 ohm resistor can be used in its place until I can get the correct component just so I can try out the set?
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Re: 4.7 ohm fuse resistor?
If you want to possibly blow more components or start a fire, sure! -
Re: 4.7 ohm fuse resistor?
use metal film . they burn up gracefullyComment
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Re: 4.7 ohm fuse resistor?
It is likely the resistor IS acting as a fuse so simply replacing it without finding the problem is pointless, What is the power supply from? What is the power supply number? I would have no problem using it just to test the power supply.Comment
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Re: 4.7 ohm fuse resistor?
It is the power supply board from a Vizio tv. I replaced the blown IC, a zener diode and a schottky diode the problems common in this set I guess. I will wait till I can get the right resistor so I don't do more damage.Comment
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Re: 4.7 ohm fuse resistor?
makes me wonder why they blew in the first place . maybe just bad design or low grade parts .Comment
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Re: 4.7 ohm fuse resistor?
Not sure why they blew but I am hoping they were defective and caused the resistor to blow also.Comment
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Re: 4.7 ohm fuse resistor?
Show us the board so we can see what we are dealing with, fusible resistor blow open circuit for reason: over current.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: 4.7 ohm fuse resistor?
The power supply board and the probe points to the fusing resistor that's bad.Attached FilesComment
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Re: 4.7 ohm fuse resistor?
other picAttached FilesComment
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Re: 4.7 ohm fuse resistor?
The pictures are too out of focus for me to read the prints on the board, it looks like that fusible resistor is for the Standby power supply, so you need to look up the spec sheet of the 7-PIN SMPS IC and the check the pins to see if it has shorted out or has very low resistance between S and D pins of that IC.
You should also check the resistance between the negative leg of the main filter cap (big black cap laying on its side) against each solder pad of the blown fusible resistor.Last edited by budm; 12-20-2020, 03:16 PM.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: 4.7 ohm fuse resistor?
I replaced the 7-pin ic, the old one was blown. I also replaced one zener diode and the shottky diode. I get no reading between negative side of main filter cap to either side of blown resistor.Comment
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Re: 4.7 ohm fuse resistor?
[QUOTE=stinger;1010157I replaced the 7-pin ic, the old one was blown. I also replaced one zener diode and the shottky diode. I get no reading between negative side of main filter cap to either side of blown resistor.[/QUOTE]
Ah the BIG missing information about that blown SMPS IC in post #1, now we know why that fusible resistor is blown since now we know what that fusible resistor being use for what section of the circuit using the requested pictures.
It always good to give us details info.
You can use flame proof MOX resistor for replacement, just match the Resistance/Wattage. For testing right now you can use 1/2W resistor and use the setup below to perform the test.
You can test the power supply board by itself to see if the standby power supply is working now or not by installing 75W incandescent in place of the main fuse, you should see the lamp comes on bright for second then it should dim down and then you can check the output of the standby power supply, if the lamp stays on bright then you still have issue on the board.Last edited by budm; 12-20-2020, 08:21 PM.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: 4.7 ohm fuse resistor?
Thank youComment
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