HELP: just completed the kit, but it won't boot. LCD remains dark. -> solved  

Re: HELP: just completed the kit, but it won't boot. LCD remains dark.

Can you please post photos of the ribbon cables both at the RAMBo board and LCD panel ends.

Peter

Re: HELP: just completed the kit, but it won't boot. LCD remains dark.

If you hook it up to a computer can you see the MK2 talking using the GCode terminal? Can you use the computer to move the print head around? If so then the issue is not the Rambo and probably something with the cables.

Re: HELP: just completed the kit, but it won't boot. LCD remains dark.

hello together,
here are the images, and -could you believe it-, i noticed that the 10pin headers at the LCD are misassembled !
this solved the mystery.
after switching around the connectors at the rambo board, so that the red marker-wire points to pin#10 instead of #1 (which is awkward), the LCD is now working (after readjusting the contrast @ R1).
💡

@david.b14:
haven't hooked up the printer to my computer until now. don't know about GCode terminal and such stuff, this is my first experience with 3D printing
🙄

thank's for the hints.

Re: HELP: just completed the kit, but it won't boot. LCD remains dark. -> solved

What? Are the images you took bfore or after your repair? I did not build mine (haaaahhaaa.... Already a week late the kit) but the images in the manual look like on your images?

Cheers,
Carsten

Re: HELP: just completed the kit, but it won't boot. LCD remains dark. -> solved

the pictures were taken before fixing the issue !
and you are right when you noticed that the layout of the connector is the same as in the manual.

usually pin#1 is marked with the red wire of the ribbon cable. that's common and that's why pin#1 is marked with a little triangle at the male and female connectors.
so i attached the cable oriented with the red wire to pin#1 at the rambo board during the first assembly, which caused the malfunction.

if i'd had a third look at the pictures from the rambo board assembly, i may have noticed that the cables there are attached with the red wire looking to pin#10.
so at our mk2 pin#10 is marked with the red wire... which still is awkward and not state of the art ;-).

i've more than 35 years of experience in electronics, if i would have had none, i probably only looked at the pictures, discarded design rules and wouldn't even have noticed an issue with the pinout of the connector(s).

Re: HELP: just completed the kit, but it won't boot. LCD remains dark. -> solved

The P1 is not meaning pin 1. on the photos i have there are more marks in the board.

https://d17kynu4zpq5hy.cloudfront.net/igi/prusa3d/hKXvZyoriDqdxtoK.large

So i would say red is on pin one in the manual.

Carsten

Re: HELP: just completed the kit, but it won't boot. LCD remains dark. -> solved

yes, P1 (and P2) doesn't mean pin#1, as you can clearly see at your rambo photo. you can see the pin numbers 1 & 2 and 9 & 10 printed right and left of the connectors outline.
but the red side of the ribbon cable has to be oriented to "P1" (or pin#10), as shown in the assembly picture, instead of pin#1 which an engineer would assume by design rules.

when you look into the installation manual, you can see that red is located at the side of the P1 / P2 printing (which means pin#10):

Re: HELP: just completed the kit, but it won't boot. LCD remains dark. -> solved

😳 😮 😯 oh yes sorry. So the ! Manual is right but Messed their Board Layout and corrected it with that fishy solution....

Carsten