Hi, I already have a mpcnc going with minirambo from the V1 store. I had been thinking about building the mp3dp printer, but ended up getting a hold of some spare parts from some reprap company that is dumping hardware cheap. The thing about it was that shipment came with a bunch of boards and motors. Ramps and mini rambos. So I got something going with Ramps. However, I have decided to upgrade (going the prusa mk2.5 route) as well as building another tiny mpcnc.
I have two miniRambos, neither are working out of the box and trying to figure them out. Here is what I know:
They appeared to be new, but cannot verify.
There is a green light on the board
On board fuses test good
There is a yellow light on the board with usb activity
I do not believe they had a bootloader on them. (could not flash firmware, would get stk500 timeout)
Using 12v to power
I tried flashing firmware thru arduino ide, but could not due to timeout. Then I tried thru a USBasp programmer. It returned successfully, but still I have no lcd. I then tried burning the stk500v2 bootloader and that returned successfully, but I still cant flash firmware directly thru arduino without going thru programmer.
I’m very new to this and I am 99% sure it is all user error. So I know this isn’t directly related to mpcnc or mp3dc right as I have a printer already to test on. But I do want to use what i learn for the next mpcnc build and I figure you guys are super helpful and have done this before. Could someone point me in the right direction? Is there a version of marlin and/or arduino I should be using for mini Rambo?
A little update. I had a 2004 lcd hooked up and that seemed to be one problem. So stole the lcd from my mpcnc and flashed latest Marlin-1CNC_MiniRambo firmware. That got me closer. I now have text on the LCD, but 1) it is inverted text/graphics not white 2) more importantly the lcd and/or rambo is super slow to respond. There is an EPROM error displayed. I can’t connect to the rambo to send M502/500 or whatever to update it .
It stays on the V1 logo screen for 30+ seconds and on the marlin logo screen for over a minute or so. I can navigate the menu and even move a stepper. But each click takes 3+ seconds
We did get further on one board. I was able to run the board/lcd screen at what appears to be a normal speed after flashing the mega bootloader twice. But still having a power issue on the 5v (4.1v) rail so I can’t barely make out the screen. Still can’t get the other board going. One of these, and I can’t remember which, I also flashed the 32u2 chip. Depending on which one I did it to, it either helped or broke it
Haven’t made any progress since. Thinking about cutting losses and moving to skr v1.4 or einsy rambo, but have to figure out what to do about my new, yet to be delivered 12v mk52 heat bed in that case.
Well you know what, I got it working… ish. So I was using the LCD from my MPCNC machine and couldn’t see the screen as stated above. But on the MPCNC, i can see it just fine. So it is not an LCD issue, cable issue or even marlin (running mpcnc build on this test). However, I just updated the marlin config to use the cheaper REPRAP_DISCOUNT_SMART_CONTROLLER. I have two laying around. Turns out the 1st one I had tried at the beginning is shot, but the second one works. I’m guessing it doesn’t have the same power needs the full graphic lcd does and so I can skate by on less than ideal power.
I haven’t tested the full printer yet as I still need to hook up the X axis and a few other things, but it may work as is. Not ideal, but should entertain me until I can plan out a move to skr or einsy. I did just have the printer scream at me due to the heatbed failure to heat past 80c, but I think that is work i need to do to tune the system. So far all other things work like motors, stops, heaters, thermistors and fans. Just seems to be low power to the LCD.
FYI for anyone having similar issues: flashing both bootloaders (mega2560 and 32u2) here, helped fix both boards… for the most part. Both boards now allow using the reset button and allow uploading firmware without timeout issues.
It did not fix LCD power issues. Probably due to a poor clones of the mini-rambo. Applying 5v to the ICSP port (via usb programmer) powers the Smart Graphic Display.
