LDO Voron 2.4 Build with All Metal Parts

[MichaelOToole]

Here we go...

Blistered IC...


Component fell off this one, it was not damaged or marked, the damage is from my poor attempt to re-seat the component with poor eyesight and no optics.
I do have the necessary equipment (trinocular microscope) but no room to set it up and I am a pretty good solderer after 45 years of doing it...

Again in hindsight, I should have tested the component before re-soldering it, it was probably faulty by then...
I've ordered 10 replacement buffers, best get out my microscope, it hasn't had any work this year...

 

[Dave32]

Hmm...
Is there any chance that the "RGB" line is shorted? (Not on the PCB, but on your string of LEDs.)

 

[MichaelOToole]

I checked the board and the leds four times, no shorts... besides, it has a 100Ω resistor on the output, that would pretty much prevent blowing the device (assuming a if 5V supply), also, the third board worked perfectly and is still working. The only way I see to cause this damage is if I connected the connector up one place, that would result in the chip/buffer getting 24V...

It's a bit of a mystery...

 

[Dave32]

besides, it has a 100Ω resistor on the output, that would pretty much prevent blowing the device (assuming a if 5V supply)

I did see that... it seems like a poor component choice though. The IC is only rated for 50mA of current as the "absolute maximum" - and in a short circuit condition that could easily be exceeded due to the standard tolerances (5-10% is common) on the resistor. In truth, 50mA is a LOT of current for a data line... they probably should have selected a different resistor value to keep that fault current a bit lower.

The only way I see to cause this damage is if I connected the connector up one place, that would result in the chip/buffer getting 24V...

Could be! It's too bad they didn't key the connectors to prevent this from happening...

 

[MichaelOToole]

Could be! It's too bad they didn't key the connectors to prevent this from happening...

My exact thoughts, I believe a keyed version exists, I'm sure I saw one previously, exact pin count and pitch...
I did scope the signal, a schmitt trigger is definitely required...

As there's a the 100 ohm limiting resistor, the buffer must source, but even so, 20-30mA should be enough for these leds.
The resistor could be increased to 150-180 ohms but the best solution would be a keyed connector...

 

[MichaelOToole]

Extra Fans
As the skirt will accommodate two additional 60mm fans, I purchased and installed two NF-A6x25 FLX fans. Needless to say they are quiet, very quiet...
It's time to update the default 60mm fans...