LED Panel Light Circuit

I have a 3 panel led overhead light which has stopped working. In examining the circuit board it seems fairly straight forward in that the board is in triplicate. 3 separate component part areas for each panel. Since it seems unlikely that lets say all three MB10F rectifier chips blew, the only thing unique are a 5-ohm resistor and some type of blue ceramic capacitor in one line of the 110V AC. The resistor reads 5 ohm in circuit, could the cap have failed? I can't get a good look at it's info. All I see on it is 070471K and Z2102.

by SteveChemist
February 16, 2024

90% of time it is the capacitor. Increase that to 100% if the capacitor top is not flat anymore, but more like half a sphere. Replace it for a capacitor of at least 200V ( 1.7 times the AC voltage) without being less than the one which failed (if the max voltage is printed on it). There is a possibility that the capacitor failure also blew the LED though.

by vanderghast
February 19, 2024

Thank you. What Farad level should I use?

by SteveChemist
February 19, 2024

The same (or larger if size allows it) than the one printed on the capacitor.

by vanderghast
February 19, 2024

Unfortunately it's unreadable. All I see with great difficulty are 2 numbers.

070471K Z2102

by SteveChemist
February 20, 2024

If you are lucky, it may be printed on the board itself. Otherwise, assuming it is a "can-like" capacitor (and not a "disk-like" capacitor), these capacitors close to the AC power are generally there to reduce the "ripples" when the AC voltage signal is in transition close to 0 volt and so, their exact capacitance is not so critical. Priorities, in decreasing order are:

  • Use one with the right voltage,

  • keep to polarization of the actual one (the side with the strip of minus sign should be at the same position on the board with the new capacitor),

  • and judge on the allowable room you have for the new capacitor (higher capacitance implies generally large capacitor size).

If you are lucky, you may "clip" the new capacitor pins on the pins of old one, temporarily, but without creating any short circuit, (close the alimentation to not electrocute yourself, that goes without saying, when you manipulate the circuit) and see if it somehow solves the problem (or if it seems to make things "better" a little bit). And if it does, do a more permanent fix by removing the old capacitor and welding the new one.

by vanderghast
February 20, 2024

Caution if you do the clip-thing, the new capacitor will probably be charged and so, if you later touch its two pins, by hand of with a metallic tool, you may be hurt with a short and metal sparks can be ejected. Wear protective glasses for greater safety. It may be excessive, but better be on the safe side.

by vanderghast
February 20, 2024

I really appreciate all your thoughtful help! I had 3 old friends that could solve any circuit board but unfortunately they're no longer around.

I like the jump idea. The cap is a small blue ceramic one. So it sounds like a 100 pF 1kV would work.

by SteveChemist
February 20, 2024

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