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Melzi V2 Board question

Posted by metamargatsni 
Melzi V2 Board question
December 24, 2024 04:28PM
Hi, I'm a new user so not sure if I've posted this in the correct section - sorry if it's in the wrong one! I wasn't sure where it should go so General it is

I have an old RepRap printer that I obtained about a year ago - it was in pieces when I got it. I believe it is / was a RepRap Pro Mendel from about 2012. The PCB was connected to the servos and bed etc but has since been disassembled again, a while ago. I bought it as 'parts'. I now would like to see if I can use the board for another project but I'm having issues communicating with the board. Initially it was missing a jumped which set the power input, but I've now sorted that issue and can get it powered by a 12v external input. If I plug it into my Win 10 PC, I can get a red light to come on, but I can't seem to get any info from it when connected. I've tried - Pronterface, Candle, Lightburn, Arduino IDE and possible others - can't remember. I've also tried changing the baud from 576000 to 115200 and one piece of software was meant to auto search but it wouldn't connect either.

The board I have is one of these -


Any suggestions as to anything else I should try of anything specific I should try with the software already tried?
Thanks!

Edited 1 time(s). Last edit at 12/24/2024 04:28PM by metamargatsni.
Re: Melzi V2 Board question
January 03, 2025 09:30AM
My advice is -- don't. Melzi boards are just not very good design, they kind of work on 12Volt supplies but just tend to flake apart on higher (and they nearly always come with laptop style power supplies, which struggle to give enough amps at the best of times to keep heater temperatures stable).


There is a write up on these, they don't even use Arduino Mega 2560 kind of 8 bit controller, they started on the much older 644 and later 1284P.

[reprap.org]

You might get Marlin onto the thing, 1.X version, but that's it.

Or, you could try Klipper, which does have a Melzi option, but it's still going to be terrible. I gave up the struggle with these things, they just are not reliable.

Arduino Mega 2560 and RAMPs is much nicer, if you change out the MOSFETS for something that can reliably supply amps. Or, the Trigorilla Anycubic, which is pretty much an all in one clone of an Arduino 2560 Mega with RAMPs. Very nice.

There are other clones of mega 2560 and RAMPs and even the poor ones are better than a Melzi, in my opinion.

Edited 4 time(s). Last edit at 01/03/2025 09:38AM by DragonFire.
Re: Melzi V2 Board question
January 03, 2025 11:26AM
Communicating with the board is currently what I'm trying to do and can't - anything further (loading Marlin etc) is a potential next step, but if I can't communicate with it, everything else is pointless.
Re: Melzi V2 Board question
January 04, 2025 04:50AM
Communications with this board is two part

a) the board has a FT232RL serial to USB chip.
Your operating system needs drivers to see this and talk to it.
Also due to ftdigate (google it) , this converter chip may be bricked (its old enough to have been caught by this)

b) the MPU has to be running some code to respond to serial.
This includes the baud rate

Most common baudrate is 115200 or 250000

Also note that some of these board have a very slow startup, 10 seconds or so. Give it a good amount of time to start up.

Pronterface is good for this.

Also Make sure your not using a charge cable! (thosse don't have data wires)

Edited 3 time(s). Last edit at 01/04/2025 05:06AM by Dust.
Re: Melzi V2 Board question
January 04, 2025 08:10AM
Thanks, I wasn't aware of FTDIGate so will do some reading, but I expect my board to be genuine and not affected.

I already own a 3D printer (Creality Ender 3 and 5), a laser engraver (Ortur LM2) and a 3018 CNC engraver, so I'm well aware of drivers, CH340, COM ports, baud rates and other such settings. When I plug the boar din, it is recognised as a COM port and I've tried baud rates from 9600 to 115200. I also know I'm not using a charge only cable as it's the cable I use to communicate with other devices (see above).

I've given more than long enough for my board to startup - I have lots of old hardware that takes time, so I'm aware that things don't start 'immediately'.

Again, as above, I've tried Pronterface and it can't access / see / communicate with the board. My computer sees the board controller but I can't get any info from it / to it via the software I mentioned in my first post above.
Re: Melzi V2 Board question
January 23, 2025 07:46PM
Did you have any luck with this? I'm about to recommission my original 13 year old Reprappro Mendel which came with this same board.
In order for Mattercontrol to communicate with it from my windows computer for the first time I had to set the central jumper to be powered from the USB plug rather than the power supply.
After that first time its now connecting fine after putting the jumper back.
I believe the baud rate it self configured to is 115200.
Re: Melzi V2 Board question
January 24, 2025 07:17AM
No, it's gone onto the back burner and I'm now trying to get to grips with an Arduino Uno and a CNC shield. With that, I've got motion but can't get the limit switches and / or homing to work - but at least I can communicate with it!
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