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Ramps 1.6 and VCC issues

Posted by allen476 
Ramps 1.6 and VCC issues
March 17, 2021 11:06PM
This is a bizarre issue.

Everything was working fine until a month ago. I upgraded to ramps 1.6 after my 1.4 board decided it wanted to go to the big chip in the sky. I ordered a kit to replace the 1.4 and the 2560. Everything was working fine. I notice my prints are quite a bit better. I then do a complete overhaul of the printer. New rods, bearings, belts, and a new Y axis motor. Another test print and it honestly is the best print I have ever done.

What the heck, I'll add auto bed leveling. I install the BLTouch. Plug it in and no power (in my defense, I forgot about the vcc to 5v jumper). So I find the new location of the jumper location and per every diagram I found, it is the two pins closest to the E0 motor connection. No problem. I power down, put the jumper on and....

I released the magic smoke from the 2560.

So I order another 2560. I check all the connections, connectors, pinouts, crimps, and do a full assessment. Everything looks good, everything is crimped correctly, the wires are in the right positions, so I turn it on and nothing happens. Good, I unplug it and put the jumper across vcc to 5v and....

The magic smoke monster appears again.

Fine, I order another 2 boards. While I am at it, I order another ramps 1.6. New boards arrive and I swap out the 2560. This time I use another new 1.6 board and 2560. The only wires I connect are the power wires on the ramps board.

I turn the power on without the jumper. I measure voltage on vcc as 4.95v. I confirm the 5v pin has 0v. I plug a jumper on vcc to 5v again and....

Another magic smoke monster...

So I am thinking that it is a manufacturing issue. The only constant through the whole thing is that the 2560 boards have been from the same manufacturer. I know that this can be done as there are posts about it. I am seeking the forums opinion however. I do have 2 different 2560 boards coming.

I should also add that I dug out a spare 1.4 board, and that is working fine with the BLTouch and a new 2560 board installed albeit very slowly though.
Re: Ramps 1.6 and VCC issues
March 17, 2021 11:34PM
where did the smoke come from?

The vcc to 5v jumper should just connect the servo 5v lines to vcc.
If you don't have anything plugged into servo plugs, it shouldn't do anything.

but, one issue is the mega 2560 power supply has always been low current.
If you have GLCD and a BLTOUCH its to much for the supply. Just the GLCD can be to much for it...

I would make your own 5v from a 7805 on 12v and plug that into the 5v pin. ie power the servos separately
Re: Ramps 1.6 and VCC issues
May 10, 2021 11:34PM
After some more digging into this, I can confirm that it is a manufacturing issue. Somewhere in the process, + and - on servo's is getting some type of debris across them. I have ordered roughly 50 boards from various sellers and all have been the same, a direct short across + and -. I have communicated this to all sellers that I ordered from. I have noticed the most have pulled the products but some are still selling them.

I would like to keep this printer on a RAMPS 1.x setup as it is the easiest to work on.
Re: Ramps 1.6 and VCC issues
May 11, 2021 02:26AM
Can you take a high resolution photo of the bottom of the pcb?

The 5v track is on the bottom and should have nice isolation from the gnds

eg here is an unpopulated ramps 1.4 I have

you can clearly see the 5v rail in the middle of the servo plugs on the left of image, nicely isolated from the surrounding traces.

Edited 1 time(s). Last edit at 05/11/2021 02:27AM by Dust.
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