Has anyone else had any problems with Melzi boards failing? I just replaced my second board in around a year. Both times the failures resulted in inaccurate temperature readings and hot end temperatures extremely high, 300c +. Seems that both times, there was some sort of feedback into the computer usb port that completely shut it down. An instant shutdown, like someone pulling the power. Aby fiveboltmain - General Mendel Topics
I too had some slight binding when i first started running mine. Even after leveling and re-leveling things, it would stick and 'jump'. I put some white lithium grease on the vertical guide rods and motor oil on the motor drive screws and cycled it up and down a few times. Haven't had the problem pop up since. An extra bit of insurance would be to glue the nuts into each side of the Z axis guideby fiveboltmain - General Mendel Topics
A wiki page on safety would be an excellent addition. I don't want anyone to have any accidents with these things. Oh man, I wish I had thought about the thermal fuse idea. Brilliant. One of those things could have saved me a alot of sanity and a couple bucks. Maybe a thermal breaker switch to avoid those 'where are the spare fuses' situations. It would be nice to have the fuse trip in sucby fiveboltmain - General Mendel Topics
The bed may be level, but double check that the guide bars for the print head are parallel to the bed.by fiveboltmain - General Mendel Topics
What are you using to produce the g-code and what settings are you running it at? Also, what kind of print time is it taking?by fiveboltmain - General Mendel Topics
I've had some time to think about this and plan on building in some safety features when I get her up and running again. Firstly, to prevent the thermister or resistor on the hot end from shorting out, I'm going see if I can install them and fill the remaining hole opening with a fireplace caulk/cement. That should prevent metal on metal shorting. Assuming the caulk is non conductive. eh Anby fiveboltmain - General Mendel Topics
In an odd way, I'm kinda glad that is happened. This way i get to learn more about electronics, and when I get the current board fixed, I'll have enough parts to start building the next printer. Once winter sets in, I do plan on fixing the current board. Just right now due to time constraints and work projects i need to print out, I'm thinking a new board would be the fastest fix. So, that beby fiveboltmain - Controllers
Hi all. I have a Reprap Mendel Pro with a Melzi controller board. Well, it appears that my temperature thermisters have shorted out on the hot end and fried something on the board. My question is this: where can I go about finding a new Melzi controller board, or a newer better replacement. Are there anyother boards similar to the Melzi that have all ports for the stepper motors and for theby fiveboltmain - Controllers
Before I had my hot bed up and working, I cobbled together a way that had pretty good results. First I put down a layer of the blue painters tape, 3m adhesive spray, and plastic netting weave vent on a roll. The plastic netting came on a roll and can be found at a hardware store. I think I got mine at Menards. I think it was in the roofing/ventilation section. Anyways, cut a section of the pby fiveboltmain - Reprappers
Another thing that may help reduce some stress on the motor may be adjusting the extrusion multipier and the heat of the hot end. When I was first expirmenting with extrusion temperatures, the lower I went, the the higher my extrusion multiplier had to be. I dunno, just a thought. On longer prints it could add up but just thought I'd throw that out there.by fiveboltmain - Reprappers
I had this happen a few times too. Loctited the set screw and also loosened up the tension on the extruder arm so the motor doesn't have to fight unecessary friction at the hobbed bolt. Took awhile to figure out how much tension was to much and get'r right in that sweet spot.by fiveboltmain - Reprappers
To be honest, I do not know about the thermistor setting in the firmware. I have the Melzi board that came with everything preloaded and it worked for quite awhile before the hot end hit critical mass. I can see where its possible that the thermister end leads might have shorted out on the heater block, but since it is a puddle of aluminum now, the evidence of that happening has dissappeared.by fiveboltmain - Reprappers
When i switch the hotend thermister wires to the hot bed connections on the control board, it gives a reading of -10C. Wow.by fiveboltmain - Reprappers
Ahhh. Good question. No. It is reading 83C. Hmmmm Got so frustrated I didn't notice this. It reads 83C even with the thermister disconnected.by fiveboltmain - Reprappers
Hi. I just had the same thing happen but did not save my hot end. It melted the aluminum. I'm never going to let this thing outta my sight when I print now. Or I will set it outside to print in the driveway. Anyways, I tried installed 3 new thermisters and it did the same thing. Do you have a heated bed? Do the temps seem to be within range for that? Any other repeatable variables and mby fiveboltmain - General Mendel Topics
Check to see that the wires on both ends of the thermister are not grounding out against the metal of the hot end block. Did it just start doing it?by fiveboltmain - General Mendel Topics
Hi all. I have a reprap mendel, bowden hot end. And boy do I have problems. The other week i started the printer and was letting everything get up to temp for the first print of the day. Rather than sit and watch it, I went upstairs to take care of some quick buisness, a few minutes maybe. When I came back down, the hot end aluminum extruder was a puddle laying on the smoldering tape and craby fiveboltmain - Reprappers