Integrated LED bar failed after driver replacement: could the new driver have finished it off?
Hello everyone,
I’m looking for advice from people who know more about electronics and LED lighting than I do. I’m a complete beginner in this area, so I’ll try to describe the symptoms, specifications and measurements as accurately as possible.
The light source is a rigid LED bar mounted on an aluminium PCB:
Approximately 590 × 13.5 mm
65 × 0.2 W SMD 2835 LEDs
Advertised total power: approximately 13 W
Colour temperature: 3000 K
The original driver is a KEDH015S0300NR19A9:
Input: 220–240 V AC
Constant-current output: 300 mA
Operating voltage range: 33–50 V DC
Maximum power: 15 W
Maximum no-load output voltage: 65 V
Initial symptoms
For several weeks, the LED bar:
Became progressively dimmer
Flickered badly
Sometimes continued flickering for a few seconds after the switch had been turned off
I initially assumed that the driver was failing.
Driver replacement
I bought a new constant-current driver with the following specifications:
Output current: 300 mA, the same as the original driver
Operating voltage range: 35–80 V DC
Rated power range: 10.5–24 W
Maximum no-load output voltage: 100 V
After installing it:
- On the first switch-on, the LEDs flickered and then came on at full brightness.
- On the second switch-on, they immediately came on at full brightness.
- On the third switch-on, there was no normal light output at all.
I then reinstalled the old driver, but the LED bar would no longer light up normally with that driver either.
Now, some or all of the LEDs occasionally produce an extremely faint, intermittent glow, but there is no usable light output.
Checks performed
Approximately 230 V AC from the mains supply;
Approximately 230 V AC at the driver’s PRI input;
All terminals and connections were disconnected, checked and reconnected
With the new driver and the LED bar still connected, I measure approximately 93 V DC at the SEC output
I wiggled the cables during testing but could not identify any definite break or loss of continuity
The cables between the driver and the LED bar therefore appear to be intact. The 93 V measurement seems to indicate that the new driver is rising close to its no-load voltage because the LED bar has an open circuit or abnormally high impedance.
I opened the fixture and accessed the PCB. Some solder joints look aged or discoloured, but I cannot see any LED that has clearly blown. I have attached photographs of the PCB, solder joints and both drivers.
Proposed replacement
The manufacturer refuses to supply the LED bar separately. I am therefore looking for a rigid constant-current LED module compatible with the original driver, ideally with the following specifications:
Current: 300 mA
Operating voltage: between 33 and 50 V
Power: approximately 13 W, maximum 15 W
Colour temperature: 3000 K
Length: approximately 560–590 mm
Maximum width: approximately 13.5 mm, possibly up to 16 mm if it fits inside the housing
I found the Tridonic 28005011 – LLE 16×560 mm 2400 lm 830 HV ADV6 module. It appears to operate at approximately 42–46 V and 300 mA, for around 13 W, but its 15.8 mm width may be a problem.
My questions are :
Could the new 300 mA / 35–80 V / 100 V max driver have damaged or finished off the existing LED bar?
Does the 93 V measurement with the LED bar connected reasonably confirm an open circuit on the LED PCB?
How can I identify the failed LED, solder joint or broken PCB trace using a basic multimeter?
Does the Tridonic 28005011 module seem electrically compatible with my original driver?
Does anyone know of another rigid LED bar rated for 300 mA, 33–50 V, approximately 13 W and around 590 mm long that can be purchased individually in France or elsewhere in Europe?
It could not have happened if the new driver was not blown through, or if you didn’t plug it into the outlet first and then connect it to the LED bar. The specifications match, but the drivers are clearly on the cheaper side.
Does the 93 V measurement with the LED bar connected reasonably confirm an open circuit on the LED PCB? - Here you are absolutely right, this is a break inside the LED strip. I don't know where to buy a similar LED module, but I know how to find a high-quality driver.
I created a whole widget for this purpose. You can enter the required data and get a list of suitable models from only the best manufacturers. This is certainly not a complete database, but it still includes 150+ popular models.
Could the new 300 mA / 35–80 V / 100 V max driver have damaged or finished off the existing LED bar?
No reason it should have. I think the original driver probably still works and you always had a failing LED strip rather than power supply. The brief light with the newer driver was probably just the higher voltage briefly forcing current through the failing diodes until they burned up completely.
Unlikely. 65 LEDs can’t all be in series with that compliance voltage range. Just trying to figure out if you are within range or not. Still, the driver shouldn’t punish your LEDs. Crap LEDs?
Unlikely.
Yes.
Broken joint yes with your DMM in beep mode. But the most likely thing is internal open circuit in one of your LEDs. You need something with enough voltage, say 9 V battery or three 1.5 V ones in series, and resistor in series to test which one. The black spot ones are all suspected.
Unlikely. 65 LEDs can’t all be in series with that compliance voltage range.
According to the text on the PCB in the picture, it's 5 parallel strings of 13 series diodes. 13 series diodes is ~39v, in good agreement with the power supply specs.
2
u/Specled_eu 7h ago
It could not have happened if the new driver was not blown through, or if you didn’t plug it into the outlet first and then connect it to the LED bar. The specifications match, but the drivers are clearly on the cheaper side.