# Installing a new mini Rambo, questions? **URL:** \ **Category:** LulzBot Mini\ **Created:** [September 2, 2016, 5:51pm UTC](https://forum.lulzbot.com/t/installing-a-new-mini-rambo-questions/3938 "2016-09-02T17:51:01Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Fancyfuchs](https://avatars.discourse-cdn.com/v4/letter/f/439d5e/32.png) [@Fancyfuchs](https://forum.lulzbot.com/u/Fancyfuchs)\ **Post date:** [September 2, 2016, 5:51pm UTC](https://forum.lulzbot.com/t/installing-a-new-mini-rambo-questions/3938/1 "2016-09-02T17:51:01Z")
Hey guys! After blowing something relating to the Z-stop on my Mini rambo, I fixed the problem and ordered a new board from ultimachine. It arrived last week and as im about to install it on my printer i noticed it is a 1.3, and the bad one coming out of my machine is a 1.1 rambo mini. My question is will this board work out of the box, or does it need flashing, updates or calibration to get it working as the old one did? I’m fine with hardware, but i’m not the best with code or the Marlin firmware. 😲 Thanks! ---
**Author:** ![Brent.I](https://avatars.discourse-cdn.com/v4/letter/b/ecc23a/32.png) [@Brent.I](https://forum.lulzbot.com/u/Brent.I)\ **Post date:** [September 2, 2016, 6:07pm UTC](https://forum.lulzbot.com/t/installing-a-new-mini-rambo-questions/3938/2 "2016-09-02T18:07:13Z")
Howdy and welcome to the forum! The 1.3 board will be completely compatible with your Mini (it comes with LCD headers installed!) You will need to flash the firmware, but it is a quick and easy once installed. First, be sure you have our latest version of Cura from: [lulzbot.com/cura](http://lulzbot.com/cura) After you have the board hooked up within the printer, plug in your USB to your computer and power on the printer. Through Cura, go to Machine -\> Add New Machine (and run through the process) Next, switch to expert mode and go to Machine -\> Install Default Firmware. Once the loading bar is done, you will be good to go! ---
**Author:** ![Fancyfuchs](https://avatars.discourse-cdn.com/v4/letter/f/439d5e/32.png) [@Fancyfuchs](https://forum.lulzbot.com/u/Fancyfuchs)\ **Post date:** [September 3, 2016, 2:50am UTC](https://forum.lulzbot.com/t/installing-a-new-mini-rambo-questions/3938/3 "2016-09-03T02:50:26Z")
So, after installing both a brand new tool head AND a new RAMBO board the printer is still not working correctly. When trying to start a print the machine attempts to clean and level at the top of the build area [in mid air] and then begins printing in mid air as well. All the z end stops trigger correctly OTHER then the Z min switch. I have tried replacing both the min end stop as well as the wire harness on them and nothing seems to solve the problem. I also tried manually tripping the Z min switch and it still wont read it with M119 I’m having the same symptoms as these threads: [https://forum.lulzbot.com/t/adjustable-heat-bed-glass-mount/38/1](https://forum.lulzbot.com/t/adjustable-heat-bed-glass-mount/38/1) [https://forum.lulzbot.com/t/ignoring-end-stops/3682/8](https://forum.lulzbot.com/t/ignoring-end-stops/3682/8) The big issue I see here is that I haven’t shorted the new nozzle (I just opened it new out of the box and haven’t had a chance to accidentally short it out somehow 🙂) and the mini Rambo board is also brand new so it cant be broken. Can anyone suggest a solution? ---
**Author:** ![Biolumo](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.lulzbot.com/biolumo/32/9340_2.png) [@Biolumo](https://forum.lulzbot.com/u/Biolumo)\ **Post date:** [September 3, 2016, 4:25am UTC](https://forum.lulzbot.com/t/installing-a-new-mini-rambo-questions/3938/4 "2016-09-03T04:25:11Z")
I will try to help as best i can as i have both replaced a mini rambo board and built my mini from scratch, so i know in detail about the non-functioning z-min limit switch you are referring to. > [@Fancyfuchs](#): > > My question is will this board work out of the box, or does it need flashing, updates or calibration to get it working as the old one did? > I’m fine with hardware, but i’m not the best with code or the Marlin firmware. It should work great as long as you use cura to flash lulzbot’s firmware to the board. Brent is correct in that with the new 1.3 board you potentially have the option of adding an LCD panel (though i’m not sure if a custom version of marlin firmware is needed for that or not). Regardless it should be 100% compatible. > [@Fancyfuchs](#): > > So, after installing both a brand new tool head AND a new RAMBO board the printer is still not working correctly. When trying to start a print the machine attempts to clean and level at the top of the build area [in mid air] and then begins printing in mid air as well. That is a little odd. But you may just need to adjust your z-offset after flashing the new firmware as your mini may be too high off the bed by default. The tip John gave me in my “Homebuilt Lulzbot Mini” thread helped me tremendously. I will quote him below. > [@John Mc](#): > > If your tool head is starting too **[far from]** the bed, there is a gcode setting you can change to adjust the z-offset. Most Minis have a negative z-offset (since “zero” is at the top of the washers once the auto-leveling sequence is complete - it’s a it more complicated than that in actuality, since it calculates a surface based on all four washers). My mini came with the z-offset set at -1.32. That was a bit too close to the bed, so I adjusted it upward (i.e. in the positive direction) to -1.22. > > Here’s a link to a post describing how to [adjust the z-offset](https://forum.lulzbot.com/t/mini-first-layer-troubleshooting/2873/1) using G-codes. That’s the method I used. > > You can also change it via a setting in Cura, if that is what you are printing with. Go to Machine-\> Machine Settings… Then enter a value in the “Z-offset (mm)” box. I’m told this software setting just adds or subtracts to the z-offset stored in the Mini, so if you want to move up by 0.1mm, you’d just enter 0.1 in the box (or a negative number to move down). I have not used this method of setting myself, however. > > The Cura method does seem like a quick way to make changes while getting dialed in, but the setting doesn’t carry over if you print with some other software, or change to another computer to control the Mini. If I were using this to fine-tune, once I had it figured out, I’d make the appropriate adjustment via the first method, and reset the Cura software to 0, just so I’d know I had it stored in the Mini. > [@Fancyfuchs](#): > > All the z end stops trigger correctly OTHER then the Z min switch. I have tried replacing both the min end stop as well as the wire harness on them and nothing seems to solve the problem. I also tried manually tripping the Z min switch and it still wont read it with M119 The z-min switch gave me many headaches when i was building my mini from scratch. Basically the z-min switch is actually non-functional “by design” because lulzbot functionally replaced it’s function with the bed leveling “5v limit switch” function. Presumably this switch did something at some point before the bed leveling was added in R&D, but after that NOTHING. And YES, i do find this practice of placing a DEAD and useless limit switch on machines that they ship out to be of poor engineering design and just awful in general. But i have voiced my annoyance of this in several threads on this forum already. I honestly don’t know why Lulzbot would go to all the trouble of wiring up a DEAD switch to ship out to people if they don’t ever intend of finding a way to update the firmware to use this switch in an emergency should the bed leveling feature fail catastrophically. But i guess with the new beta firmware the bed leveling is now “smart” like on the new Taz6 and it will actually re-clean and re-level if it fails within a small margin of error. So i guess in effect this switch will never be functional. But again, it boggles my mind why they bother to include it if that is the case. But now you know. Your board is not bad. Nor are you going crazy. ---
**Author:** ![Fancyfuchs](https://avatars.discourse-cdn.com/v4/letter/f/439d5e/32.png) [@Fancyfuchs](https://forum.lulzbot.com/u/Fancyfuchs)\ **Post date:** [September 3, 2016, 6:12pm UTC](https://forum.lulzbot.com/t/installing-a-new-mini-rambo-questions/3938/5 "2016-09-03T18:12:44Z")
Hi Biolumo, Thanks for the post back, very helpful! I’m working through your comments bellow and I had another question. In looking at the wiring going from the Z-stops into the mini I seem to be confused with why it is connected the way it is. The Z- min Stop has navy blue and blacking coming out of it, but it doesn’t run to the Z-min stop on the board. In the OHIA for the mini it shows this connection going into another port on the board, mainly the bottom 2 pins of the ICSP next to the marker X18. If that is correct then what is running into the Z-min stop port with the red and black wire? AKA step 10 in the OHAI? Thanks! ---
**Author:** ![kmanley57](https://avatars.discourse-cdn.com/v4/letter/k/13edae/32.png) [@kmanley57](https://forum.lulzbot.com/u/kmanley57)\ **Post date:** [September 4, 2016, 12:20am UTC](https://forum.lulzbot.com/t/installing-a-new-mini-rambo-questions/3938/6 "2016-09-04T00:20:23Z")
That is the bed leveling signals, the Red is the wire from the nozzle and the Black is the ground side. ---
**Author:** ![Biolumo](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.lulzbot.com/biolumo/32/9340_2.png) [@Biolumo](https://forum.lulzbot.com/u/Biolumo)\ **Post date:** [September 22, 2016, 1:33am UTC](https://forum.lulzbot.com/t/installing-a-new-mini-rambo-questions/3938/7 "2016-09-22T01:33:11Z")
> [@Fancyfuchs](#): > > Hi Biolumo, > > Thanks for the post back, very helpful! I’m working through your comments bellow and I had another question. > > In looking at the wiring going from the Z-stops into the mini I seem to be confused with why it is connected the way it is. > > The Z- min Stop has navy blue and blacking coming out of it, but it doesn’t run to the Z-min stop on the board. In the OHIA for the mini it shows this connection going into another port on the board, mainly the bottom 2 pins of the ICSP next to the marker X18. If that is correct then what is running into the Z-min stop port with the red and black wire? AKA step 10 in the OHAI? > > Thanks! Yes, the lulzbot dev team seems to have just done the first workable hack that came to mind when originally designing the mini. Presumably before they added the auto bed leveling feature they had a functional z-min switch. With the bed leveling feature this required them to replace the z-min stop switch with a red 5v wire coming from the nozzle (therby acting as a switch). The blue and black wires probably do indeed go to this redundant z-min switch. Why this switch is still wired up and included on Mini’s being sold is anyone’s guess and i assume just comes down to laziness. or perhaps some sort of internal testing procedure during assembly? But the basic answer is that the red wire is the one you want in z-min. The blue and black wires theoretically could be ripped out completely without compromising any functionality.