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Rerouting electronics outside of enclosure  

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DerBierBaon
(@derbierbaon)
Eminent Member
Rerouting electronics outside of enclosure

Hi folks,

I can't seem to find all the information in old posts about the known issues with rerouting the Rambo mini and PSU to the outside of an enclosure.

To get straight first: I plan to make the extensions for the motor cables, sensor/thermistor, end stop and heating element wires as short as possible.
I already repositioned my LCD to the outside of my enclosure and had major issues with extending the flat cables (now I know that this was to be expected...).

Therefore I plan to print a second Rambo enclosure (maybe remix the original) to put the rambo to the outside and leave the old one on the printer. Then solder up a distribution board to leave all the electronics' cables stock and just connect them to this board inside the old rambo case. Said board then should have three cable bundles from it to the rambo (sensors and endstops on one, motors on two and heating elements on three).

To easily disconnect the inside from the outside I plan to use something like a D-Sub for the motors and another for sensors/endstops and something more beefy for the heaters (maybe XT-60), that I want to mount on the wall.

So my questions are:

Are there any wires in the mentioned looms that should not be extended (similar to the LCD flat cables)? PINDA? Thermistors?

As extra connectors can mean increased fire hazard due to overheating, is there any concern regarding the proper Molex connectors and/or the D-Subs? Are there concerns due to the general increase in the amount of connectors? I.e. signal noise?

Help would be greatly appreciated. 🙂

Greetings
DerBierBaron

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Posted : 16/08/2018 5:00 pm
JoanTabb
(@joantabb)
Moderator
Re: Rerouting electronics outside of enclosure

I believe d connectors have a maximum 1amp current rating per pin, this could cause issues with the motors and would not be acceptable for the extruder heater or the heat bed.

your flat cables may need to be even longer and this could lead to corruption of the signals

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 23/08/2018 1:13 am
DerBierBaon
(@derbierbaon)
Eminent Member
Topic starter answered:
Re: Rerouting electronics outside of enclosure

Hey Joan,

thanks for the reply. Yes after some research I found out a couple of things about connectors:

-D-Sub is not the same as D-Sub 🙂 the "regular" quality D-Sub ususally rates up to 1 or 1.5A, but then there are some industrial grade D-Sub connectors that work with up to 5A. The major issue with D-Subs though is their low life span considering their mating cycles... they often go out of spec fast after 100 mating cycles which is a bit fast considering that I want to do major maintenance outside my enclosure (changing fried components for example).

-There are other connectors out there that fulfill my desired requirements but the get expensive very fast (along the lines of Harting connectors ca.120€ ~140$ US for a set of male and female). So one alternative connector I found might be Centronics connectors. These used to be the connectors for serial ports on LMPT i.e. printers and such before USB was around 🙂 these have supposedly higher mating cycle numbers (haven't found any numbers, just people in forums stating this) AND higher current rating (minimum I found was 5A) AND way cheaper (~10$ US for a set).
EDIT: after looking further into this apparently the only Centronics connectors that have such a high rating are these here

So I am thinking of using Centronis connectors for motors and another set for sensors/endstops in this project and maybe stick with the Molex terminals for the extruder and heated bed.

What do you guys think? Is anyone interested in seeing this project built? If so I am considering documenting it for this topic and updating as I go (might be a while for an update though, am in the process of learning to print PC properly on my MK2.5 and then want to do the Full Bear Upgrade as well as the electronics rerouting.

So let me know if anyone's interested in the process. I can also include the Full Bear Upgrade in the posts.

Regards DerBierBaron

P.S.: the flat ribbon cable can not be elongated more than maybe 150mm from the stock length, I tried... The display will power up and show the menu as normal but MOst of the time the SD wouldn't read in my case ("No SD-Card" notification with the card plugged in).

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Posted : 25/08/2018 10:19 pm
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