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warning: ramps boards with bypassed jumper

Posted by edfrombordeaux 
warning: ramps boards with bypassed jumper
May 11, 2015 07:41AM
Hi,
I have just bought several RAmPS 1.4 boards from different vendors and many of those boards had the jumper for choosing the microstepping bypassed under the header which make the jumper completely useless (see picture). Why would they bypass a jumper with a track on the PCB and still solder the header to put a jumper is beyond my comprehesion but this can certainly lead to problems if you are not using the 16 microsteps default.

Cheers,

Erik
Attachments:
open | download - RAMPS_14.jpg (364.7 KB)
Re: warning: ramps boards with bypassed jumper
May 11, 2015 08:56AM
Thanks for the heads up! thumbs up
Re: warning: ramps boards with bypassed jumper
May 11, 2015 09:24AM
There was another thread sometime in the last month or two that mentioned the same thing. It was though to either be a design mistake or intentional since almost everyone uses 1/16th microstepping anyways. Since the headers weren't installed on your board, that would lend credence to the latter as it saves the cost of those ├╝ber expensive 2x3 pin headers. If a user doesn't want 1/16th microstepping, a razor blade or utility knive can easily cut the trace and full stepping enabled, or pin headers installed for using jumpers to select what microstepping is desired.
Re: warning: ramps boards with bypassed jumper
May 11, 2015 12:00PM
Actually the headers were installed, we had to unsolder them to see the tracks. That's why it doesn't make sense because they paid for the headers and the jumpers.
Re: warning: ramps boards with bypassed jumper
April 26, 2016 08:06AM
Hello
same situation here...
To control you must verify with a multimeter with board alone and control the circuit between pair of pins is open.

I didn't desolder all the pins.
You can use a plier to pull away all plastic bases from the 6 pins and then use a cutter.





Re: warning: ramps boards with bypassed jumper
April 27, 2016 04:52AM
I took a single LiPo battery and simply burnt away the traces by shortcutting them with the battery. No need to pull off the plastic or anything.
Re: warning: ramps boards with bypassed jumper
April 27, 2016 05:00AM
Quote
o_lampe
I took a single LiPo battery and simply burnt away the traces by shortcutting them with the battery. No need to pull off the plastic or anything.

Super!!

But the first two pins are connected to something on the board, I measured resistence after cutting the trace..
So this could be a risk..

Edited 1 time(s). Last edit at 04/27/2016 05:30AM by pieri70.
Re: warning: ramps boards with bypassed jumper
April 29, 2016 07:44AM
There is a 100k pull-down resistor at MS1 pin, but there wouldn't flow any current when connecting the LiPo.
Re: warning: ramps boards with bypassed jumper
October 12, 2016 09:30PM
It took awhile to find I had the same problem. The traces are visible when the header removed. A real pain to try to cut the jumper. GREAT idea by o_lampe!! Connected a 12V SLA battery across the pins and blew the jumper away completely, no residual resistance. Since I had to do them all, I made a two pin connector with a foot of #22 cable. Plugged it in and then connected to the battery. Thanks for the tip.
Re: warning: ramps boards with bypassed jumper
October 13, 2016 07:20AM
Interesting find!

I have one of those too.

Unfortunately i don't have a program that can open the original PCB files from [www.reprap.org] to see if the bridge is present there.

I might believe this was done by some cheapskate just to save on pin headers/jumpers, but failed to tell all the DIYers selling these boards on eBay that the jumpers are not needed. grinning smiley
After all, if you cut one wire, you can always fix it by soldering a header later. And if you are not experimenting with it, then the three jumper configuration is just constant. No need to spend jumpers to it.

My board says "Robotale" and has this problem.


Also, it reads HIF_Team there and you can see the bridge between pins is there.


EDIT: Checked those files from wiki and they are not bridged.

Edited 1 time(s). Last edit at 10/13/2016 11:20AM by Veesta.
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