Sometimes RJ45 connectors work, sometimes not

Hi Everyone,

We have our Mendel (Techzone Laser Cut) all set up and connected to my PC with Repsnapper. We are moving axes and getting the extruder turning. However, our tip manager module is not staying reliably connected to the mainboard, we have swapped the RJ45 cable with one that we know is working and are still getting the same problem -sometimes it works and others, it does not. We are guessing that it must be the connector units on either the mainboard or the tip manager board or both that are messed up somehow.
Has anyone had this problem? We are bouncing around ideas, such as hardwiring the two together, which would be annoying due to having to mess around with the boards and potentially break something and the inability to remove the cable afterwards. We really don't want to have to send our mainboard back to Techzone -again...

Any ideas, suggestions?

Thanks!

Jacqueline

Never had that problem, although I also have a techzone electronic board (monotronics, it uses that tip manager child board too).


I would check with a multimeter that your assertion (connector acting weird) is true.

Move the cable around during measure to reproduce the vibrations, etc.

It will be a load of work, given all the connections to test, but I don't see any other way to get sure...


Looks like Techzone motto should be "It can work. Just don't ask when."

Yeah, I like that Techzone motto too Their kits are not for the faint-of-heart for sure

We will go ahead with your good ideas for checking out all the connections.


Thanks,

Jacqueline

There is a wiki page which could help you - hopefully it's still correct.

It details the wiring of that pseudo-ethernet cable techzone use.

We've checked things out and things seem to be ok all-around, although an email to Techzone suggests that it may, once again for us, be a "cold solder" problem. We are more inclined to think that it is the nature of the stiff pseudo-ethernet CAT 5 cable that pulls when the unit moves or is moved that is breaking the connection. I received some good advice on the IRC chat about securing the cable in some areas, but it cannot be easily attached all over because the carriage moves a lot which means the cable moves a lot too! The real solution may be a softer, more flexible cable...

We'll keep on working away and I will list our results/progress/solution/outcome in case in may help others.

Jacqueline

BTW -merci pour le "link" DeuxVis.

Edited 1 time(s). Last edit at 09/28/2011 06:57PM by JLudlow.

I also read somewhere that a straight (non crossed) ethernet cable is what you need for a replacement. You should be able to find a softer one in general computer stores.

You need "patch cables". Normal CAT5 cables are solid core and will break if you bend them backwards and forwards over and over again. "patch cables" should have stranded cores to make them flexible.

Edited 1 time(s). Last edit at 09/29/2011 05:46AM by nophead.

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I have flat wire like phone wire only wider and RJ45 connectors to go with it. It is stranded and bends well. I have LOTS of it left from the days when Ethernet cable was COAX.

I'll send you a couple of cables to try, if you'll tell me the length and your address by Private Message. We can see if that fixes the problem. By the spelling of your name, I'm guessing you might be French? If so, it will take two weeks for my envelope to get there at a rate I'm willing to pay from the USA.

To limit stress on the connector and board, can you cable tie the cable tightly just before it enters the connector? ANY flex there would bring a cold solder joint on the RJ45 front and center. Still, if THAT is the problem then 30 seconds with a soldering iron will fix it. Lets try the much more flexible flat cable first.

DeuxVis -thanks, we are looking!

Nophead -thanks for your input -that was pretty much what we were thinking. By the nature of being printers and pretty well constantly in motion, any cables really need to be flexible and made to flex a lot in these machines. We'll look out for "patch cables".

JED -PM sent out, thanks for the offer! We have been trying to figure out how to secure the cable just before the connector but there is not really a lot of places to do so! The tip manager module is secured with one silly little screw and pivots a lot on that too, which I suppose could be good if the cable wasn't so stiff...


Jacqueline

Oops. The big spool of flat cable I have on the shelf at home turned out to be 6 wire (for RJ12) not 8 wire. I think I have 8 wire on the shelf at the office. I'll be there on Wednesday and get some then.

One possible problem with this solution is signal noise. An Ethernet cable is tightly wound twisted pairs (the biggest difference between Cat-3, Cat-5, and Cat-6 is the tightness of the twist and the isolation of the pairs). That lets the electronics use balanced signals to minimize electrical interference and radio frequency interference.

My flat wire won't do that. Whether it matters is determined by the signals that go through the wires. I went to the TechZone site but couldn't find the tip manager board that you mentioned.

BTW: Most short Ethernet cables ARE patch cables and stranded wire. If you CAN bend it in a sharp angle easily (DON'T), it is stranded. Non-stranded cables have a LOT more resistance to bending.