Just picked up a M2

[jprochnow]

Just picked up an early M2 and have a question about things I should change. It does have the 2 power supplies instead of the 1 24v unit. What benefits do I get by swapping these out. Is the current heated bed on this compatible or do I need a new one of these as well? I'm assuming the Rambo is older, will this be compatible with 24v? Attached is a picture showing what I have on the way to me. If you look a few threads down I was looking for used one for my son's school. Luckily I picked this one up and need to figure out what I need to change so I can donate it to my son's school.

[Tim]

The short answer is that if the RAMBo has a component in the back left corner that looks like a large square bright yellow capacitor, that thing is a 12V circuit breaker. It sort of blows up violently if hit with 24V. With one of those, to upgrade to 24V is a pain, as there is no convenient way to convert it to an automotive fuse. I think I am the only person to have done so (and it was an ugly hack). If there's an automotive fuse plugged into a socket in the back left corner, then your life is a lot easier if you choose to convert to 24V.

I should add that the only reason that I did the upgrade to 24V was because I wanted to take part in the beta testing of the dual V4 extruder, all of which is designed only for 24V. If it weren't for that, I would not have upgraded from the dual 12V/18V supply, because there are not enough advantages to make it worthwhile. The 24V doesn't really buy you anything, but getting the upgrade kit will cost you something (to answer your question---yes, you need a different heated bed for 24V, although there's another ugly hack solution posted on a thread here somewhere, if you feel comfortable taking a knife to the bed heater).

I'd say you've got yourself a great machine. Run with it.

[jprochnow]

Ok i'll run it as is.... But is there a link to how to modify the rambo for 24v? I did see that there is a advisory at the top of this forum. Maybe I will be able to send it in?

[insta]

Eh, I disagree with Tim, but not enough to compose as nice of a reply. The safety issues with overloading the RAMBO plug cannot be overstated though. Stick with PLA or PET, so the bed temps aren't too high.

[jprochnow]

Ok so at 19v how much current can the hb pull? What is the connector rated for? Couldn't I avoid the whole problem if I run a solidstate relay? Then I don't have all the power going to the rambo and the 19v goes directly to the solidstate relay.

[rpollack]

Please read through the Safety and Operator bulletins pinned to the top of this forum topic. If you have the yellow fuse, you need to contact support and have the electronics replaced. We will supply the replacement electronics. If you don't have the yellow fuse then we recommend retrofitting your machine to 24v as discussed in the Operator Bulletins. You need to be at 24v to upgrade to the new v4 extruder too.

Rick

[jprochnow]

Thanks a bunch Rick. I will check that out right away when I receive it. Is there any good links to see the v4 hotend? I'm interested in seeing what this looks like.

[ednisley]

Couldn't I avoid the whole problem if I run a solidstate relay?

That's a straightforward modification that will serve you well:
http://softsolder.com/2013/10/11/makerg ... hermistor/



That requires a DC-DC SSR, not the usual DC-AC version.

I used Powerpoles for the high-current connections: they Just Work.

You should stabilize the platform cable to avoid having it break from repeated flexing. This is from before I added the SSR, but it gives you the idea:
http://softsolder.com/2013/07/05/makerg ... ilization/

[Tim]

The safety issues with overloading the RAMBO plug cannot be overstated though. Stick with PLA or PET, so the bed temps aren't too high.

Okay, I have to admit that I have never worked with ABS, and so have never run the bed temperature higher than 90C (for PETg and PET+).

[Rara]

I've been running a fair bit of ABS through my V3a, on glass at 100-110 and Buildtak at 70-90 after having hit and miss luck with adhesion. Seems to do fine as far as the hot end goes, but I did solder my connections at the Rambo for the PSU inputs after I kept burning up connectors. If Rick recommends 24v upgrade though I'd err towards what he suggests, for obvious reasons.