Arduino/Ramps went crazy after unsoldering D1

So I had a spare voltage regulator so I disconnected the D1 and powered the arduino with 7V through the barrel connector.

However, with the USB connected and the printer power supply on (12V on the RAMPS and 7V on the arduino) either the pc randomly states that there a usb device malfunctioning or the host programs cannot connect, or both.

If I disconnect the printer PSU and I connect via USB to the arduino, all is good.

If I disconnect the barrel connector and use 12V on RAMPS + USB for the arduino I have the same problems (Arduino not recognized).

Since the problem occurs only when the RAMPS is powered up I am thinking that maybe I am forgetting something (other than unsoldering the D1). Could there be anything else?

I have 2 working arduino clones and both get the same error.

Tomorrow I will resolder the D1 and apply the 7 V to see what happens.

I also tried increasing the voltage to 7,5V, just in case to make sure the voltage regulator is getting a high enough input voltage but this didn't help...

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Self-sourced Mendelmax 2.0-based Reprap Machine -- Ramps 1.4 & Mega 2560 -- DRV8825 (Z@1A, [email protected], [email protected], E@1A) -- genuine E3D v6 direct setup -- 350W custom silicone heated bed -- ABS 1,75mm -- Marlin 1.1.0-RC7 -- Cura 15.04.6

I read somewhere that through the barrel connector you need to supply 9 volts.

D1 is only used to feed ramps power into the mega voltage regulator

mega 2560 from [www.arduino.cc]
Input Voltage (recommended) 7-12V
Input Voltage (limits) 6-20V

I would say you have a dead voltage regulator on the mega, its really easy to do (creating a short from 5v to gnd will do it every time, normally is is done with plugging in 3pin mechanical endstops in backwards)

The voltage regulator is only used when you power the mega from the vin pin (ie ramps) or via the dc jack.
The voltage regulator converts input voltage into 5v needed by the board

testing

remove the ramps
power the mega with just a dc jack 7v dv should be fine. Measure a 5v pin I suspect it will not have 5v on it.

Edited 1 time(s). Last edit at 09/29/2016 10:56PM by Dust.

I doubt it is the 5V regulator. With the ramps disconnected I get 4,85V on the regulator with an input voltage of 7,5 V. Furthermore, I get the same problem with 2 separate Arduinos... I don't get it..

That said, I guess a damaged AMS1117 would lead to a not wotking display/card reader... And not to an arduino that can't be recognized...

Btw, I already tried with another usb cable and usb port but still no joy...

Edited 1 time(s). Last edit at 09/30/2016 07:49AM by icefire.

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Self-sourced Mendelmax 2.0-based Reprap Machine -- Ramps 1.4 & Mega 2560 -- DRV8825 (Z@1A, [email protected], [email protected], E@1A) -- genuine E3D v6 direct setup -- 350W custom silicone heated bed -- ABS 1,75mm -- Marlin 1.1.0-RC7 -- Cura 15.04.6

... do you have a display attached?

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Yes I do.

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Self-sourced Mendelmax 2.0-based Reprap Machine -- Ramps 1.4 & Mega 2560 -- DRV8825 (Z@1A, [email protected], [email protected], E@1A) -- genuine E3D v6 direct setup -- 350W custom silicone heated bed -- ABS 1,75mm -- Marlin 1.1.0-RC7 -- Cura 15.04.6

... then it's drawing more current, than the 5V-regulator can support.

Best is to add an external 5V source for the display ...

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

I know the 5V regulator is an issue with Adruino. However I don't see how this can be the root cause:

1. The AMS1117 is working.
2. The issue remains also when the display is unplugged.
3. If USB is plugged in, I can connect to the printer and everything seems to be working (of course I cannot move anything because the PSU is off). The second I turn the PSU on I get

Serial com errorystem.IO.Ports.SerialErrorReceivedEventArgs

The host program is repetier host. Some time later I may or may not get a "device attached to this computer is malfunctioning" popup.

If the AMS1117 gets in some undefined state I imagine this could be it. However, with almost no load (display unplugged) and input voltage >7V I don't see how this might happen.

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Self-sourced Mendelmax 2.0-based Reprap Machine -- Ramps 1.4 & Mega 2560 -- DRV8825 (Z@1A, [email protected], [email protected], E@1A) -- genuine E3D v6 direct setup -- 350W custom silicone heated bed -- ABS 1,75mm -- Marlin 1.1.0-RC7 -- Cura 15.04.6

Ok, hold tight. I found the root cause.

There was voltage across the earth and GND terminals of the PSU (??). It is of course a chinese PSU. So I shorted the earth and ground rail and now everything works.

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Self-sourced Mendelmax 2.0-based Reprap Machine -- Ramps 1.4 & Mega 2560 -- DRV8825 (Z@1A, [email protected], [email protected], E@1A) -- genuine E3D v6 direct setup -- 350W custom silicone heated bed -- ABS 1,75mm -- Marlin 1.1.0-RC7 -- Cura 15.04.6