Rara wrote:So right now I've got a late 2012 machine with all its original hardware on it. Last night I believe the bed PSU bit the dust and had my first hardware-related print failure (am I initiated finally?). I've been paying just enough attention to things to know there have been some changes and upgrades going on but I wasn't planning on fixing unbroken things. So given that, I thought I might start a thread to discuss the whats, whens, whys and verdicts of the various things that have changed..sort of an open thread for now, and after some of the blanks are filled in, make one succinct post and edit it in here at post 1? Open to suggestion, of course!
(Trimmed the rest.)
Your machine has a 19V brick for the electronics, steppers and hot end, and a 12V brick for the heated bed. It has 12V fans all around, with the electronics enclosure fan and extruder fan wired in parallel. The firmware is probably set to PWM the output to those fans at 155/255, giving about 12 volts average. The newer machines use a single 24V power supply. (The new supply still has no on-off switch. Keep your surge strip or whatever you currently use to turn power on and off!). The 24V PSU is wired to all three pairs of input terminals on the RAMBo. The 24V units use the same two 40mm 12V fans, but now they are wired IN SERIES for the electronics and extruder fans. When you buy the 24V upgrade kit, a chunk of wiring harness for the extruder is included, and that change includes wiring places the fans in series. The firmware setting for that output now gets changed to 255/255, supplying 24 volts to the fans in series, giving 12V for each. You'll need a 24V bed cooling fan. MakerGear now has in stock, I believe, both 40mm and 50mm 24V ball-bearing fans.
I got a pack of 24V ball-bearing 40mm fans online (not MG), and I did NOT change out the wiring harness -- I just replaced the electronics fan and extruder fan with 24V units, and changed the firmware to run the output at 255/255 -- so I'm running a unique setup with two 24V 40mm fans still in parallel. I did get a couple 50mm 24V fans from MG, so I have a spare in case I (yet again) stick the M3 hex driver into the wrong place. (Oopsie X n.) Using the 50mm 24V fan for the bed/part cooling (angled).
Tim is pretty much right on with the hot end. My M2 was from March 2013 and had the nichrome-wound ceramic-ball heater (V3) with the thermistor taped/stuck on the nozzle. The V3B currently shipping uses a resistive cartridge heater in an aluminum block, and the heaters are available in various resistance (hence voltages), so when you order the 24V upgrade kit, you'll get the 24V heater. You can get the hot end kit only for your 12V/19V machine -- just let Karen know in the order comments what machine you have and they'll make sure you get the right heater. The thermistor is on the aluminum block as well, no longer on the nozzle, and there's some temperature drop from the block to the nozzle, so with the V3B 24V heater, you need to set your temperatures about 15-20C higher (so, 215-220 for PLA, 245-ish for ABS). Not to worry about melting the PEEK at these settings -- jimc has run even higher (255, jim?) continuously without damage.
I believe the up-coming V4 is all metal, so the PEEK worries go out the window. MG is also working on a dual-extruder setup which will use the V4 hot ends. Pictures are posted in another recent topic on the forum.
Tim is also right on with the RAMBo itself. If you look at the corner of the board near the left front of the machine, you'll either see a yellow encapsulated part or a blue (15A) automotive fuse. The former is the 1.0 RAMBo (the revision is also silk-screened on the top of the board in fine print, near the middle), and this is the one that needs the yellow solid-state breaker removed and replaced. The one with the blue fuse is either 1.1 (like mine) or 1.2. You won't have the 1.2 on your machine. There's an electrostatic sensitivity on the 1.2 -- just so you're aware if you upgrade your board --- and MG has shipped a fix to owners of it. If you get a new RAMBo, that should already be taken care of.
I can't answer you about the various changes in connectors. I don't think they've changed since my M2 shipped. The wiring harness that comes with the upgrade kit will probably solve most, if not all, your connector issues, because it replaces all the connectors that are up on the extruder and hot end.
As for the bed heater, yes, it is now a 24V rectangular unit that covers the entire bottom of the aluminum plate except for maybe 1 cm along the back. Elsewhere on the forum you'll find a hack for cutting a wide trace in the old heater to turn it from (basically) four elements in parallel to two groups of elements in series, making it an effective 24V heater. I hacked mine like this, but it's pretty ugly and I don't recommend it --- you may be more talented than I am with an X-Acto knife, however! (I saved the old HBP just in case -- but I actually use it as a wall plaque because of the nice laser-cut M2 logo! I should get it mounted on a nice finished cherry board.... yet another "thing to do".... sigh.)
Hope this helps you out, Rara. Good luck deciding whether to go 24!
Dale