MiniRambo Timeout

I recently just moved to the great Alaskan tundra and have been trying to get my MPCNC put back together since the move and have just been running into more and more problems. I guess I wasn’t too surprised that a lot of the mechanical components were damaged after being transported 4000+ miles, but what’s been really stumping me for the last few days is that I can’t seem to get my miniRambo to respond at all. I’ll give it power and try to connect with Repetier, which it does and all the LED’s turn on. But when I try to send commands, like M119, it hangs up and gives a “1 command waiting” message, then after 30-60 seconds it’ll give an error saying “communication timeout - reset send buffer block”. If I don’t send any commands and just let Repetier do it’s thing, it’ll give this same error in the log every couple of minutes.

I thought maybe if I reflash the firmware that would solve things, but Arduino also fails to upload giving the error message “avrdude: stk500v2_getsync(): timeout communicating with programmer”

I’ve tried different firmware versions, different Arduino versions, different USB cables, and different power supplies and get the same results every time. Google hasn’t led to much other than me thinking either the bootloader & firmware got wiped somehow OR the chip on the board is fried. All the fuses are still intact on the board, so I’m hoping that it’s not the chip being fried.

Any recommendations on what I could test next would be greatly appreciated.

There should be a lot of data on the console output.

  1. Double check the PSU voltage amd polarity. Do you get LEDs when there is no USB connected?
  2. Are you sure you have the right port and baud rate?
  3. Are the fuses ok?
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  1. PSU output reads as 12V 5A, is also correct. When powered and unplugged from USB, LED1 is solid yellow and LED7 is solid green.
  2. Port number is correct, I've even uninstalled the drivers and reinstalled, tried switching ports, tried different computers - same result. For baudrate I'm assuming its 250000 since that's what is in the Marlin firmware settings for this. I've tried out every other baudrate setting in Repetier as well, no change.
  3. All 3 fuses are still intact. I swapped them out with backups I have on hand just in case, no change.
Another point to note:

When I connect to the board with Repetier, it gives a message “No start signal detected - forcing start” - Google led me to checking out the bits/second property in the COM settings in Device Manager. I ran through all of those settings, still no luck

May have killed the board, but it’s not quite the dry season up there yet. Make sure you ground the crap out of everything, by December the humidity is stupid low and static gets crazy. Watched a dude send about a 1 inch arc to the body of his powerbook once. Laptop shut off, but luckily came back on.


You don’t happen to have repetier server accidently installed do you? It will take the com port and not share.

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Good point about the humidity, I’ve lived in cold climates like this before but never considered it an issue since I never used the machine during the colder months. My new place has a heated garage though so I’m hoping I can use it year round now.

I did have Repetier server installed, just uninstalled it and rebooted my computer and still no change. I also thought maybe if I plug back in the LCD controller I could see if it’s even booting up and all it gives is a blank, but lit up, screen. I tried different orientations of the cables for the controller thinking maybe I flipped a cable on accident, all other orientations leave the screen off. I also tried a brand new screen I got for a different project, same result except this one emits a high pitch continual beep while powered.

Maybe this is my sign to upgrade to the full Rambo for dual endstops…I do have a spare RAMPS board that I might hook up in the meantime so that I can fix the mechanical issues while I wait for a replacement board to ship in.

Yeah. I think the mini might be toast. Have you checked with ultimachine?

Okay, now that we got that out of the way, where in AK are you?

New board has been shipped. Jeff, I’ll get in touch with ultimachine and see if they can confirm our suspicions of it being a dead board.


Barry, we just moved into Eagle River, AK a week ago (just outside of Anchorage). I’ve never seen mountains before, it’s absolutely gorgeous here!

Cool! Used to drive by there on the way to weekend trips in Anchorage. Lived in North Pole for almost 20 years. Back in the states now though.

It’s a pretty small state. Everyone knows everybody.

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Oddly enough more people live in Dayton OH, than the entire state of AK… It’s weird.

Yeah, but the ratio of ursines capable of eating you is much, much lower in Dayton. Not to mention the days per year with a strong likelihood of losing an appendage to frostbite/exposure.

Very true. We have black bears, but not many. I’ve done the frostbite thing. Do not reccomend. Froze my palms and fingertips moving equipment out on the flight line at -40 or so without gloves.

Black bears are cuddly, compared to grizzlies or kodiaks, and moving equipment outside in sub-zero conditions sans gloves is all on you. In the word of Yosemite Sam: Idjit! :wink:

Oh, yea, totally my fault. Had to give the cold weather safety briefing for a long time after that. Black bears in AK will actively hunt people. Browns will generally leave you alone unless you scare them, or get between them and their cubs. Crawled out of my tent one morning to find brown bear tracks bigger than my stretched out hand right in front of the tent flap. I never went far enough north to have to worry about polar bears, but had a girlfriend’s mom get chased around a truck a couple times by one. First lap got the door open, second one she dove in and pulled the door closed behind her.

Just had a mandatory 3 hour Alaska safety training last week going over bear (and other wildlife) safety. The weirdest thing was on the drive back home we saw our first black bear just walking down the side of the road without a care in the world.

Also got my replacement board in this morning, should be back in business soon enough!

Moose are more dangerous than bears. There’s more of them, and they are attracted to people’s gardens.


Also, The Double Musky is a really good place to eat. South of Anchorage. Kinda spendy, but worth it!

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Plus, if you give a moose a muffin, it’s going to want jam to go with it…