LED light flashing trying to fix LED driver board

[Welchs101]

Hi i have an LED garage light. It has two bulbs/strips of led lights in it. One of the bulbs is flashing. I dissassembled the light to get to the LED driver board.

i am enclosing pictures.

given that one works and the other does not (ie...flashing) i thought i should be able to fix this.....or at least determine what is wrong.

the led driver board basically had "two" drivers on the same board. I began probing using my multimeter trying to find differences between the two. Now there may be diff i did not find but one difference i did find was diode6 (D6).

for the side that worked i measured diode D6 (RS1M...i think this is part number) using diode check and it measure ~0.5V. I measured D6 on the side that does not work and two things: (1) i did not hear the beep (2) the voltage measured was ~ 1.3V.

I removed D6 from the bad side thinking this is the bad part......i measured D6 removed form the PCB board and it measured good....or at least same as D6 onthe good side ~ 0.5V.

I then measured across where D6 was on the bad side (ie...with D6 removed from pcb board) and measured the exact same voltage of ~ 1.3V.

Now i am not an expert but does this mean that the D6 ont he bad side was shorted? If so how do i find the shorted part........if not any ideas on how to proceed from here

[Welchs101]

I was not sure which "group" to post the question in.....if this is not the correct group let me know which one to put it into and i will move it..........

[stj]

your on-board reading may be effected by a charged capacitor.

did you try swapping the led strips over?

[Welchs101]

i am not sure what you mean by swapping the led strips over. If my measurement was affected by a charged capacitor.......why didnt the other LED driver have the same issue?

[petehall347]

might be a shorted capacitor . or that ic
most likely a cap i would think .

[Welchs101]

i thought i checked all the caps........none were shorted ...i will check again.

[petehall347]

i see one side of d6 goes to r4 ..where does the other side go to ?

[noppa]

Solder joint on F2 seems bad.

[Welchs101]

the other side of d6 goes to ... i am not sure..........i will try and find out.

regarding F2.......i think you mean F1........this solder joint is bad as i had to desolder wire so i could work on the pcb board.

[sam_sam_sam]

Be aware of the fact that if it a LED module and if a portion of is still working the switching power supply may not allow it to stay on because the current is not correct

I was working on some of these LED fixtures over the weekend and this was the issue with some of these lighting fixtures

[stj]

in short - a bad led will make the strip flicker.
which is why i asked if you swapped them around - to see if it's the leds, or the board

[Welchs101]

stj, i now see what you're saying...........that would have been a wise thing to try before i desoldered the diode.......let me see if i can resolder it back in without breaking it

[Welchs101]

Hi, i have not had time to work on this lately but i am planning ot work on this.

I did have a question concerning the flashing? Currently i have the pcb board removed from the led lights. instead of "reconnecting" and "swapping" drivers to see if the flashing follows the driver ......could i just connect each LED-strip to say a 9v battery? would this work? will this cause a problem/hurt the devices?

[stj]

wont work,
you need to meter the current they draw.

[sam_sam_sam]

Originally Posted by stj

wont work,
you need to meter the current they draw.

And to expand on his comments just because the led strip might light what you do not know if any of the LEDs on the strip are pulling to much or not enough current so your best be to know for sure that either led strip is good or bad or if the led driver is working correctly or not this why we have suggested that you swap led drivers to check the driver functioning or not

[Radio Fox]

The readings you get on the diode check setting of your meter doesn't make sense to me. If the diode reads 0.5v when it is removed, then you should get that same reading (or perhaps slightly less) when it's in circuit. Reading 1.3v across the same 2 points on the PCB when the diode is in and out of circuit cannot be right, as you say it reads 0.5v out of circuit.

Are you sure that you are keeping the polarity of the probes the same way round when taking all measurements (common [black] lead to banded end of diode)? And the same when probing the pads on the PCB with the diode removed?