I am very confused with this issue I started having out of nowhere today; that the SD card being in the SKR Pro (from powerup or during powered state) is the only way I can have the TFT on.
The issue occured today sporadically and I have again an issue which has occured at the same time where I can no longer connect to the SKR board from the PC.
Anyone have this issue before? Right now I try to reflash firmware but on SKR I am not successful and on TFT I have no GUI despite lights on board being on (knob LED is not active). Thus I attempt a TFT firmware upgrade first then an SKR Pro upgrade.
TFT upgraded as I have 2 microusbs i can trigger its ‘on state’ by inserting spare microusb into skrpro.
Now having issues installing the firmware on the SKR Pro on a microsd which previously installed the firmware correctly / without issue. Will do some repeated attempts.
I cannot update the firmware - perhaps because I am trying to update to the same firmware thus it does nothing? → not this as I tried afterwards to flash some random firmware without success as ell.
The TFT display still is totally inactive until a microsd is inserted in the SKR Pro.
Would appreciate insight from anyone here, I am a bit lost for ideas.
Note currently I have all stepper motors and end stops disconnected so to isolate root cause issue better. Only TFT connectors are connected and power via USB (again; USB not detectable from PC to SKR pro is another issue I must solve)
Also tried with proper PSU without success.
Also I have the power jumper on USB mode as now I am working from USB connection to solve this issue.
SKR Pro is not communicating still with the TFT or the PC
Not sure what steps I can take next. Have ordered a programmer in-case i have some BL issue but that would be in my opinion strange as it interrupted mid cut and this behavior started.
You have a really strange problem. Did anything else change/happen when it got funky?
When the SD card is installed and the display is on, do you then see the controller over USB?
For this to have happened, you almost certainly have broken hardware on the controller.
Can you start out with a good high-resolution picture of the board, top and bottom? If possible, take a picture of the board top when power is on so we can see the status LEDs. With and without the SD card if possible.
No → I never see any USB activity again on this board from linux when monitoring in terminal “dmesg --follow”
While squaring the motors all stopped and started intermittent buzzing “buzz Buzz buzz buzz”. This concerned me so I powered off, opened up and checked all connections but nothing identified. From this point on the TFT and PC could no longer connect and the TFT screen was off permanently (I only learned that microsd turns it on later but it still does not establish connection).
I take this time to cleanup the cables and redo each connection while investigating the skr.
When inserting micro SD card into SKR the blue light flashes quite intensely and extremely briefly which seems to trigger the TFT on state.
I will take some photos shortly.
The SKR Board isn’t too bad on cost so I’ll probably buy another one today, just a bummer that shipping time is so slow.
note - the ribbon connectors for the TFT aren’t plugged into anything on th other side. I just found them easier to remove from TFT than from SKR.
Pretty annoyed as I will go on a 2month vacation in 1 month and the boards have a 2 month delivery time thus I won’t be able to continue on machine for 4-5 months #vent
One last thing you can try is to move that jumper I highlighted in green over to the USB side, then plug in a USB cable while your SKR is off. Does the PC see it?
I suspect not, and I suspect this is a blown board.
some hot glue i had previously to fix the dupont connectors while I was waiting for JST connectors to ship. Did a bit more damage than I expected to the plastic.
I have tested with this jumper changed and indeed the PC does not see it.
So how exactly do you think I have blown this board? What can I do to prevent blowing the second?
This is a really strange issue. I’m not sure how it could’ve hsappend while homing, unless perhaps there’s some kind of intermittent wiring short.
I suspect you heard when the board died- and you did the right thing to power down at that point.
When 3V3 isn’t present, the processor on the SKR is dead.
If you want to troubleshoot further, I’d measure the 3V3 and 5V rails with and without the SD card in.
You could also try only connecting marlin mode and only connecting TFT mode cables to your display. The two grey cables are only used in Marlin mode, the black cable is only used in TFT mode. The TFT should power up with either the black cable (only) in, or the two grey cables in.
It would be interesting to know what the TFT does with either config, with and without the SD card in (4 tests)
I’ll redo all the wiring to be sure - I know at one point some weeks ago an end-stop may have been shorting intermittently but again I wouldn’t expect that to be an issue really since the microswitches are just leaf switches anyway right?
Will start this test you recommended shortly. Can you note quickly where i should measure the 3.3/5v to get most info?
Also just bought a new board with 6 new drivers, will ship to a neighbor and receive after my vacation
The 3V3 regulator will blow if you short 3V3 to ground. Fun fact, the V+ pins on the end stop connectors are 3V3. So shorting V+ to G on the stop connector will damage the regulator. (Note that shorting V+ to Signal won’t damage anything, though shorting 5V to signal will damage the CPU pin. This is why the connectors are 3V3.)
Most likely, the V+ pin was shorted to ground, or to signal while the stop switch had signal shorted to ground. This would be the most likely point of failure.
Given the initial condition, however, it js possible that something conductive got into the SD card slot, where it shorted the 3V3 to ground when the SD card was out, and the damage to the regulator took a while.
Probably a replacement can do the trick. If you could solder in a new one, they’re cheap. Possibly an external variable resistor could be connected to put voltage into the 3V3 bus (the V+ connector on an end stop lug would do it, lol.)
The processor is likely not damaged, as it didn’t get overcurrent, but without 3V3, it doesn’t get power.
