.:madworm:.'s photos

That saved a lot of money. Let's see how long it lasts.

...if I went to a repair shop. They'd probably want to replace the whole thing and not just add a new rubber-thingy.

KiCad: www.kicad-pcb.org gerbmerge: ruggedcircuits.com/gerbmerge/ I made this a long time ago and never used it. But it shows that simple PCB panelization is doable with open source tools. The routing paths and tabs were added with KiCad, which was a bit of a pain. You have to enter the start / end-points of the sectors in x / y coordinates. Specifying radius and angle is not yet possible. You also need to add '--no-trim-gerber --no-trim-excellon' to the Makefile. Otherwise the routing-paths get chopped off outside the bounding boxes. The option to subtract the solder-mask from the silkscreen (KiCad gerber file creation) unfortunately upsets silkscreen duplication in gerbmerge, so it can't be used. The boardhouse should take care of that.

and fully cleaned.

So far I've managed to kill 5 of these PT4115 LED drivers, and I don't think that I've abused them - at least when compared to what I've done to other devices that survived no problem. The failure mode is very consistent. Either it stops working altogether (no more switching, output switch permanently open) or the output switch is permanently closed and the LEDs suffer over-current. Common to both manifestations is that the DIM pin shows unusually low resistance (about 6Ω) to GND. This makes me believe that this pin gets trashed somehow. Therefore I will test if adding a Zener + dropper resistor will help to protect the chip. Voltage clamping at 5V1 definitely works, so lets see how things go. Adding a Zener + resistor is the way to go. No more premature demise.

The result is pretty good. I think I could use an even smaller tool (spear-point drill). Using sub-1mm fluted end-mills can get a bit tricky, especially if they're not of the short and stubby kind. They break quite easily - and cost a lot.

1k dropper resistor + 5V1 Zener diode BZX84C5V1.

That method worked pretty well with a board that had top and bottom copper pour and quite a lot thermal vias.

Almost bacon!