Weird Marlin issue with LCD

Hey Guys

Wondering if anyone can offer any thoughts as to what's causing this.

So my system is Prusa i3 clone, with RAMPS 1.4 running Marlin.2.1x bugfix
Changes made before the problem occurred: Installed a BLtouch sensor and edited the firmware to enable the sensor.

So whats happening now is, that as long as the arduino board is connected to the PC via the USB everything works fine. If I disconnect the USB cable, everything works fine.
But If I turn the machine off and then on again, Marlin reboots, and keeps on rebooting nonstop. It never gets to the main menu on the LCD. If I plug in the USB cable while its doing its constant rebooting, then it will boot into the main menu normally. So basically the machine will not boot up properly unless it's connected to my PC via the USB.

Any ideas ?

Edited 2 time(s). Last edit at 07/30/2023 02:30AM by Lenny25.

Ramps board have power issues, a lcd is all you can add (and that is pushing it) add in a bltouch and it needs to much current on 5v

remove 5v/vcc jumper that powers the servo 5v pins and instead make your own 5v supply from 12v to plug into the 5v pin and connect the gnds

Edited 1 time(s). Last edit at 07/30/2023 08:19AM by Dust.

Thr 5V regulator on an Arduino is inadequate to power an LCD. It overheats, causing it to reduce the output voltage. Your options include:

- Connect a couple of silicon rectifier diodes in series with the 12V input to the Arduino to reduce the input voltage. This transfers some of the heat dissipation from the regulator to the diodes.
- Instead of powering the display backlight from 5V, power it from 12V through a series resistor. A 180 ohm 0.5W resistor would be about right.
- Provide external 5V to the Arduino instead of powering it from 12V
- If the rest of the printer is worth it, dump the obsolete Arduino/RAMPS combo for a good 32-bit board.

Edited 2 time(s). Last edit at 08/01/2023 02:00AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
Dust
Ramps board have power issues, a lcd is all you can add (and that is pushing it) add in a bltouch and it needs to much current on 5v

remove 5v/vcc jumper that powers the servo 5v pins and instead make your own 5v supply from 12v to plug into the 5v pin and connect the gnds

Thanks very much! Sorry that I need to ask a few stupid questions:

1) I have 5v (16A) and 12v (18A) outputs on my power supply, are you suggesting that I connect one of the 12v to the 5v pin (next to the VCC and PS ON pins)? Or should be using 5v supply?
2) Where would I connect the ground (negative) to?

Thanks so much again!

" 12v to the 5v pin" no, never ever ever do that!
I sad to use the 12v to generate a 5v, how is up to you

If your power supply also has 5v, connect the 5v to the 5v pin The grounds will already be connected

@Dust - Hey thank you so much!

That works perfectly!