Solved LDO V0.2-S1 Picobilical 5V stopping MCU from starting

[AndyT]

Printer Model

LDO V0.2 S1

Extruder Type

Other

Cooling Type

Other

Hi

So have an issue with I believe boot order/power on a brand new LDO Voron 0.2 S1 kit. I'm using an old RPI 4b I had laying around instead of buying a RPI Zero W2.

With the electronics connected, the MCU will not boot. Neither green light shows on either the SKR Pico or Picobilical board.

RPI is powered from 5V ADXL Hat (5V from Picobilical board).

If I power the RPI from USB and turn that on first, then power on the 24VDC supplying the SKR Pico and Picobilical board, it all starts up.

If I power from the HAT, I can get it start by first pressing the reset buttons on both the SKR Pico and Picobilical board, then in Klipper restarting the firmware. Then both green LED on the SKR and Picobilical board light up and klipper boots.

Not really sure how to proceed here. Having to press the reset buttons isn't viable.

Delving further, if I power the RPI from the picobilical 5V hat, the MCUs won't start. If I power the SKR/Picobilical on first and then on the RPI using USB power (5V hat power disconnected), MCU's won't start.

However, if I power on the RPI first via USB, then power on the MCU's, it starts properly.

Any ideas?

 

[claudermilk]

Oh, I remember this struggle! Make absolutely, super certain the 5V leads on the Picobilical frame PCB and on the Pi GPIO hat are really in there secure. It can feel like they are, but getting those particular ferrules seating in the terminal blocks are really fiddly on these boards for some reason. Once you have a wire tightened down, give a good tug to make sure it doesn't come out. Once I got that sorted it all powered up fine.

 

[AndyT]

It powers up just fine, but the MCU's have to be reset via their PCB buttons in order to boot. If I power the RPI first via USB, then power both MCU's both boot just fine.

 

[Yaaj]

Got two LDO kits.
The only decent terminals were on the Picobilical.
The ADXL hat terminals were pure crap, as well as the SKR Pico ones.
These terminals have sheetmetal pins, and one broke as soon as I tightened it. BTW they are too small.
As a result, I unsoldered all terminals, and replaced them with good quality plain metal components I have in the drawers. All. Except on the Picobilical.
Even had one terminal that was not threaded on the SKR !

 

[AndyT]

Ok but the issue isn’t power connections.

 

[claudermilk]

The SKO Pico and Picobilical MCUs got flashed, right? If they have, and the power connection is good then I've got nothing.

 

[AndyT]

It's a boot issue to do with the USB ports on the RPI4b apparently. I have a work around, testing it later.

 

[claudermilk]

Oh, Pi4. I've read there's some issues there. I have a Pi3b in mine and it works fine.

 

[AndyT]

Oh, Pi4. I've read there's some issues there. I have a Pi3b in mine and it works fine.

Funnily enough, I'm just setting up a RPI3B. Sick of the issues with the 4 so will return that to Amazon.

 

[claudermilk]

Or store it away for future use. I have another 3 and a zero 2W hoarded for future projects after Pis became unobtanium.

 

[AndyT]

Wow, a RPI 3B just fixes everything. All my issues are solved.

 

[transonic_gecko]

Wow, a RPI 3B just fixes everything. All my issues are solved.

I'm late to the party, but had the exact same experience and fixed it the exact same way. Pi 3B works flawlessly, but I had to do the same thing with the Pi 4 in order to get it to boot. The LDO guys on Discord didn't seem to acknowledge the issue...

 

[AndyT]

I'm late to the party, but had the exact same experience and fixed it the exact same way. Pi 3B works flawlessly, but I had to do the same thing with the Pi 4 in order to get it to boot. The LDO guys on Discord didn't seem to acknowledge the issue...

I suggested on there that they add to the build notes that the RPI4B is not compatible.