I recently moved house, and after careful packing of my printer, the X endstop seems to not be working. When I hit Home X in Repetier host, the X axis moves to the endstop then seems to just stop instead of going to park position. The other two axes work fine, but this one just stops and then I cant send any commands. Any ideas? Cheersby twicx - Printing
Hmmm. See, I was hoping to avoid more messing about with the electronics. In an ideal world, I'd like to be able to just go down the normal route of PSU>Rumba, Rumba>Heatbed. I'm pretty sure that the rumba is rated for 11A, and if the resistance of the board is measuring 1.5R, then by my calculations, that's only 8A. So it should be fine, right?by twicx - Controllers
Hmmm, so then I probably don't need the ssr realistically, right?by twicx - Controllers
I'm just now running test prints of a new PCB heatbed. It's 300x300mm, with a measured resistance of 1.5 ohms. Currently, I'm using a RUMBA board, an ATX PSU @12V/52A and an SSR relay. But by my calculations/research, the RUMBA offers protection of up to about 11A, and this should only be drawing something around 8A. To compensate for heavier current draw, I'm also running 2 parallel 18AWG wiresby twicx - Controllers
Bit of a mediocre day shopping for parts yesterday. The closest I could get was 2 x 33R and 2 x 39R power resistors. I'm fairly sure they're 3W and 5W judging by their size. The plan is to use the 2 x 33R on the 2 x 5V connections, and the 2 x 39R in parallel across the 3.3V. These are the resistors in question, I put a standard 1/4W resistor in the middle for size comparison: I'm still not suby twicx - Controllers
Ah I think I've figured it out now. This is on the side of the ATX case: So that means I'm going to need resistors across Ground and 1 x Red Wire (+5V), 1 x Orange Wire (+3.3V) and 1 x Purple Wire (5V StandBy), so that they reach minimum loads, am I correct? If so, then by my calculations, these power resistors should do it: 27R @ 1W across the 3.3V (122mA) 47R @ 1W across the 5V (106mA) 47Rby twicx - Controllers
Crap. The fans I have are 0.96W, and I don't have any power resistors remotely large enough. According to this site (http://makezine.com/projects/computer-power-supply-to-bench-power-supply-adapter/), a 10R resistor at 10W across the +5V and Ground is enough for most PSUs. But it looks like I can also test it with the fan in there first to see if it does generate enough of a load. If it shuts ofby twicx - Controllers
Ok interesting development. I had a look at the original Felix 1.5 instruction manual, cos that used an ATX supply too. In that one, the Green wire in the ATX was soldered to one of the Ground wires. The Green one in that PSU is labled "PS/On" on the actual circuit board for the power supply. Now when I looked at the circuit board for this one, what do i spot? A green wire with PS/On where it hitby twicx - Controllers
Ok so after far too long, I finally have a new heatbed and SSR. The problem was with DHL, they ended up having it in their posession since December 28th, and it only arrived yesterday. Wonderful. I'm now making a start on the long journey to doing all the upgrades. The first thing to tackle is the ATX power supply. I'm making a start now on tidying up all the wiring, removing excess wires etc. Iby twicx - Controllers
the good news is that I have those ordered now, with the heatbed too. The bad news, exams on the 6th and the parts aren't due to arrive till the end of january.by twicx - Controllers
So this looks like a good option, right? ebay ssrby twicx - Controllers
That's a damn sight cheaper. I might go for that, or, at the very least, use it as a reference for finding what i need. Thanks again!by twicx - Controllers
Quotedc42 No, not for the heated bed/relay section. But you will probably need a load on the 5V output from the ATX supply to keep it happy. If you will be using an LCD display, the backlight of that display may be enough load for the 5V output, and by connecting the backlight there instead of to the Rumba 5V output, you will keep the 5V regulator on the Rumba cooler. Ok grand. My instinct is toby twicx - Controllers
FINALLY getting a chance to put some time over this. I've been working crazy hours, and studying for my professional exams, so my printer has been in parts for the last few weeks! From looking at this again, I think a solid state relay seems to be the easiest solution, but as there's always a risk of damaging something, I'm doing all the research I can. First and foremost, from looking around, iby twicx - Controllers
Cheers for that! I might actually be ok with just the normal sevenswitch. The resistance of the heatbeds are between 1.1 and 1.4 ohms, and if the 15A is going to be just for the heatbed, I might be ok. Wouldn't leave me with much in the way of tolerances, but it could be ok. I guess my best bet would be to get the heater, measure its resistance, then decide on what to do then.by twicx - Controllers
Now this seems like a really interesting solution! A little board and some mods to the firmware, I think that's manageable! As far as the MOSFETs in parallel, I had a read through the SevenSwitch research pages, and had a little look at a few other sites and I'm just wondering if there's any reason why I couldn't just use a different MOSFET to handle the higher current? For example, IRF3708 is gby twicx - Controllers
Ok so after looking at the SSR option, I'd rather avoid having to wire up two plugs for the printer. What's the deal with the mosfet option? How is that wired up? Is there a guide somewhere?by twicx - Controllers
Quotedc42 Although those Fotek DC-DC SSRs are easy to wire up, unfortunately they have quite a high maximum voltage drop (1.6V, see ) and hence there will be a lot of heat to get rid off. You would be better off using 2 mosfets (chosen for very low Rds(on) @ 4.5V gate voltage) wired in parallel. I still don't get how I would connect these up, or what kind of mosfets to go for. But that aside, dby twicx - Controllers
Quotedougal1957 Quotetwicx So by the sounds of it, I'm going to need something between the Rumba, the power supply and the heater(s). This makes it tricky. The first problem is the mounting points. Because of the design of how the bed is mounted to the z axis gantry, the mounting points for anything is going to be a tricky issue. My printer (Felix 1.5 Rev.E) uses 3 mounting points for the Heatedby twicx - Controllers
So by the sounds of it, I'm going to need something between the Rumba, the power supply and the heater(s). This makes it tricky. The first problem is the mounting points. Because of the design of how the bed is mounted to the z axis gantry, the mounting points for anything is going to be a tricky issue. My printer (Felix 1.5 Rev.E) uses 3 mounting points for the Heated bed. One is in the centreby twicx - Controllers
I've come across a few. Apart from the ones on aliexpress, I have a few shops bookmarked on my laptop, but it'll be tomorrow before I can get at them. The silicone ones, although they seem to be good solutions, they seem messy between relays and using mosfets etc. and it still leaves me with the problem of the awkward mounting holes on the aluminium plate. I'd feel more comfortable with the PCB,by twicx - Controllers
I'm in the process of doing some much needed upgrades to my printer's heatbed, and I'm trying to workout my best option. The existing heated bed was done with 4 x 4.7R power resistors (aluclad type) and the temperature maxed out around 70C. I have just mounted 4 x 2.2R power resistors, but I haven't tested them yet. They're 8W as opposed to the 15W ones that were there, and although they have aby twicx - Controllers
Quotecdru Quotetwicx 2. This one has 2, but from each +12V contact point on the board, there's about 6 x 18AWG wires coming from it. So I'm assuming that if I'm grouping 3 x +12V and 3 x GND for the heat bed, they should all come from the same +12V and GND contact point on the board. I've tried to take a photo here, but it's quite tight in the case! You can see that at both of the 12V contacts, tby twicx - Controllers
Quotedc42 A few notes: 1. If you connect your heated bed sections in parallel, they will take 14A each at 12V (perhaps a little less after voltage drop in the wiring). That's 56A total, close to the limit of your ATX PSU, and you haven't allowed for the current draw of stepper motors or fans yet. Unless your heated bed is huge, you should get enough power if you apply 12v to two sections connectby twicx - Controllers
Quotecdru Quotetwicx So from what I can tell, the plan is to take 3 x 12V wires and 3 x GND wires from the ATX and "group" them so that they all connect to the HB + and GND respectively. Then take a single +12V and a single GND from the ATX and go to the board power (for all the other stuff) and then one last +12v and GND for the fans.If you do that, your heated bed and fans will always be on wheby twicx - Controllers
Quotecdru You can run multiple wires to share the current. Presuming the supply and ground are the same gauge, you'll need just as many ground wires as supply. A single larger gauge wire may be easier to route and provide more flexibility than a bundle of smaller wires. If you run all 4 traces in parallel, and each trace is .85 ohms, then your overall resistance is 1/4 that, or .2125 ohms. To kby twicx - Controllers
After building a new PCB heater, I ran into a bit of a problem. The PCB Heater is in 4 sections, each with a resistance of about 0.85R. I know that's very low, and puts a tonne of power across it, but I wasn't getting near enough heat out of the last few heater solutions I was using. Long story short, I fried my 21A power supply pretty quickly. So, I invested in a new 700W ATX PSU, rated for 58Aby twicx - Controllers
QuoteTraumflug When used as heating elements, the specified power rating doesn't matter. Typical RepRap hotends use 3W resistors to heat with 25 watts, after all. What matters is the achieved temperature. It shouldn't exceed the rated maximum temperature. Ah I see!! Max temp is 190, so considering I'm only looking for about 100, I should be ok, right?by twicx - General
So having found that my old heatbed couldn't get up to the right temperatures for ABS, I've been battling a serious redesign over the last few days. And now I'm stuck. Originally, it had 4 x 4.7R power resistors in parallel. Now just a note on this, these were from the original manufacturer, and were rated for 15W. I'm fairly sure they were operating WELL outside their recomended tolerances. Anby twicx - General