Testing dead XHP50.2 P60 module - LED or driver?

[smurcod]

I’ve got a P60 module with a “Cree XHP50.2” LED and “5 mode 5A driver”. I knew when buying it that would be pushing the friendship a bit due to the lack of heat sinking with the P60 modules.

The module driver is supposed to have temperature control and the module was working exceptionally well until last night. A freshly charged battery and under 1 minute of use killed it. Just when I was thinking how impressive the output was. Different battery and host shows it is definitely dead.

My question is, I was almost sure it would have been the LED that died from overheating. However, when checking the LED on the diode setting on a multimeter, all 4 segments with dimly light with the probes in one direction. To me, that suggests the LED is okay and it’s the possibly driver? I have never checked an XHP50.2 3V LED with a multimeter and haven’t got another to compare. I’ve checked the LED voltage and it seems to be 0.3V when not lit, but I’m unsure what a effect a dead LED would have on the driver output voltage?

The other question- I have a digital power supply and can hook up 2.8V (mid range for a 3V XHP50.2) across the LED. Is that likely to damage the driver? I could pull it apart but I’m waiting for the AliExpress seller to see how they want to proceed.

[FearOfTheDark]

Cant you just de-solder the MPCB from the driver?

[smurcod]

@FearOfTheDark

Cant you just de-solder the MPCB from the driver?

I could, but I don’t want do any disassembly unless the seller gives me the okay.

[Marc_E]

@smurcod

However, when checking the LED on the diode setting on a multimeter, all 4 segments with dimly light with the probes in one direction. To me, that suggests the LED is okay and it’s the possibly driver?

Yup, that would be my guess. An LED is unlikely to just turn off when overheating, it’s more likely to go through a glarey angry blue, possibly smokey phase first to give you some warning. And i don’t see that 5A in a P60 pill is nearly enough to kill an XHP50.2 dead like that.

I wouldn’t put power into the driver from the LED end though.
I also wouldn’t think that 1 minute at 5A in a P60 is enough to kill a driver, just sounds like a faulty driver/component to me, but i don’t have much experience killing drivers.

[smurcod]

@Marc E

@smurcod

However, when checking the LED on the diode setting on a multimeter, all 4 segments with dimly light with the probes in one direction. To me, that suggests the LED is okay and it’s the possibly driver?

Yup, that would be my guess. An LED is unlikely to just turn off when overheating, it’s more likely to go through a glarey angry blue, possibly smokey phase first to give you some warning. And i don’t see that 5A in a P60 pill is nearly enough to kill an XHP50.2 dead like that.

I wouldn’t put power into the driver from the LED end though.
I also wouldn’t think that 1 minute at 5A in a P60 is enough to kill a driver, just sounds like a faulty driver/component to me, but i don’t have much experience killing drivers.

I might just cut or unsolder one of the LED wires. Then I can at least test the LED. Like you say, I’m expecting the LED is going to be okay given it dimly lights up using the multimeter’s diode mode. I’m not sure if it suddenly stopped working or slowly failed. It looks okay with no obvious signs of overheating. I had two flashlights on comparing them when it died, I went to raise the XHP50.2 it was no longer on.

The seller has been good so far, but not having English as their first language can make interpreting the replies difficult. At the end of the day at least it’s not an expensive flashlight that has died.

[smurcod]

I just cut a wire from the driver to the LED and applied 2.8V directly to the LED. It lit up fine, so the driver is the problem.

[Lightbringer]

If the LED gets hit with nasty overcurrent, it’ll likely go blue and dim, then quietly die of heat-stroke.

A single-chip emitter may blow one of the bond wires and go dead instantly, but I haven’t seen that in a while.

A multi-chip emitter may blow a bond wire or two, and might take out half the emitters first, before the rest go.

I’d look to the driver first if you’re pushing an XHP.

[Lightbringer]

@smurcod

I just cut a wire from the driver to the LED and applied 2.8V directly to the LED. It lit up fine, so the driver is the problem.

Ah, there ya go. Answered too quickly…

[smurcod]

@Lightbringer

If the LED gets hit with nasty overcurrent, it’ll likely go blue and dim, then quietly die of heat-stroke.

A single-chip emitter may blow one of the bond wires and go dead instantly, but I haven’t seen that in a while.

A multi-chip emitter may blow a bond wire or two, and might take out half the emitters first, before the rest go.

I’d look to the driver first if you’re pushing an XHP.

Thanks for the info. I assume there would be visible damage if it was “cooked”?

[The_Whispering_Galle (The Whispering Gallery)]

I had an issue with a drop in where the solder joint between driver and pill was weak, and failed due to heat (I think because the pill expanded due to the temp increase, pulling the weak joint apart).

[Lightbringer]

@smurcod

Thanks for the info. I assume there would be visible damage if it was “cooked”?

Depends. Might be discoloration, might just lose efficiency (ie, permanently dimmer), etc.

[smurcod]

@The Whispering Gallery

I had an issue with a drop in where the solder joint between driver and pill was weak, and failed due to heat (I think because the pill expanded due to the temp increase, pulling the weak joint apart).

Yes, that’s a good point. I did check it early on (visually and with a multimeter) and it appears okay. Certainly not the best soldering (and there’s only a single solder joint), but I was getting some voltage at the LED.

The seller’s responses now leave me wondering if they’re going to send a new driver or not… If they don’t I won’t be buying anything off them again. I don’t think they participate on this forum- like a couple of other sellers do.

[smurcod]

@smurcod

The seller’s responses now leave me wondering if they’re going to send a new driver or not… If they don’t I won’t be buying anything off them again. I don’t think they participate on this forum- like a couple of other sellers do.

The seller finally responded after two requests for them to please send out a new driver- they said they’ll only do that if I will pay for postage!? So great customer service…… Suffice to say I won’t be buying from them again. This was my second purchase from them and I’d left a 5 star rating (the only rating) for this module.

So, I decided to pull the driver out and see if anything was obviously wrong (expecting to see something burnt.) This is what I found.

Going by the solder “blobs” on the end of the wire and on the circuit board (circled) that wire was never soldered down properly. It was loose when I removed the driver. I’ve soldered it back on and the module is now working again.

Out of interest, connected to a bench power supply at 4.0V it maxes out at around 7W power.

[smurcod]

So I thought I’d fixed this, but I hadn’t tried changing modes. It was stuck on high permanently. The AliExpress seller- DanceLite - hasn’t responded to the above picture. So I won’t be buying from them again.

I had a Convoy 5000mA 17mm driver lying around (it wouldn’t go past 2800mA at the tail cap with an SST40 in a different flashlight) so I fitted that. It’s working really well with the XHP50.2 3V and is hitting 5 Amps at the tail cap.