HQ Sixteen: Chin Light Failure

The COB LED module I stuck under the HQ Sixteen’s chin worked well at first:

Last month it began to flicker and I eventually caught it in the act:

That’s taken with the phone’s selfie camera from the quilt’s viewpoint, which is much too close for the camera’s focus, but you get the general idea.

Pulling it off, putting it on the bench, applying 12 V, and letting it heat up produced this:

That’s with the voltage backed off to 8 V to avoid burning out the exposure.

Letting it cool a bit:

You may recall I stuck the aluminum backing plate to the HQ Sixteen’s case aluminum body with some heatsink tape and the thing ran just warm to the touch, so I suspect the initial failure had little-or-nothing to do with overheating and a lot to do with buying stuff from eBay.

That suspicion is supported by having two more of those in the drawer with their failed chips circled.

So a better design is in order …