How to adapt the ATX PSU for Rostock MAX

[dtgriscom]

I have my branny new Rostock MAX v2 kit, complete with Voltek ATX PSU. I'm a bit confused by the directions in the (preliminary) manual, but rather than bug Gene I decided to bug the rest of you

First, I want to list all the things that I THINK I know, but could be wrong on. If I am wrong, please let me know:

1) All the Rostock MAX needs is plenty of +12V (the yellow wires), the associated ground wires (black), and a switch between the power line (green) and a ground. The other lines (+5V, -5V, -12V, +3.3V, sense wires, etc) can all be left disconnected.

2) All the yellow wires are the same, as are the black wires. So, you can use whichever you like and ignore the others.

So, if both of those are true, here's my plan (again, please let me know of any flaws):

1) Cut off all of the connectors, leaving the wires as long as possible

2) Collect the set of wires I actually need (from the current manual: six yellow, seven black, and a green)

3) Open up the PSU (yes, it violates the warranty, but what do you think cutting the connectors off does?), and remove every unused wire at the circuit board.

Result: no big bundle of unused wires, no risk of shorting, cleaner machine.


... sound good?


Thanks,
Dan

[Captain Starfish]

All but the last step. Yes, it would be cleaner. But who cares about a mess you never see and that never gets in the way?

I personally grouped the redundant wires by colour (so shorting isn't an issue), taped the bundle ends to insulate, rolled 'em into a tight bundle and taped the bundle to hold it. These bundles all sit tucked up in the PSU bay where I don't have to think about them. So far, less work. And who ever goes into the PSU area ever anyway?

More advantageous is when it comes time to add (for example) the obligatory RAMBO driver fan. Tease out a ground and 5 or 12V line depending on your fan, solder a connector on and plug the fan in. PSU doesn't even need to come out of the base. Easy.

[bvandiepenbos]

yep, that's how I have built all of our machines.
a little more work, but well worth the cleaner build.
you may consider leaving a 5v, just in case you add something in the future that is 5v.
don't cut off the wire for power switch, I don't remember at the moment if it is green or brown.

[dtgriscom]

All but the last step. Yes, it would be cleaner. But who cares about a mess you never see and that never gets in the way?

I personally grouped the redundant wires by colour (so shorting isn't an issue), taped the bundle ends to insulate, rolled 'em into a tight bundle and taped the bundle to hold it. These bundles all sit tucked up in the PSU bay where I don't have to think about them. So far, less work. And who ever goes into the PSU area ever anyway?

More advantageous is when it comes time to add (for example) the obligatory RAMBO driver fan. Tease out a ground and 5 or 12V line depending on your fan, solder a connector on and plug the fan in. PSU doesn't even need to come out of the base. Easy.

You know, those are some really good points. I tend to over-clean my projects; if doing so doesn't improve the results, and may prevent a future mod, then it probably ain't worth the effort.


Thanks,
Dan

[bubbasnow]

2) Collect the set of wires I actually need (from the current manual: six yellow, seven black, and a green)

what you should do is while you have this open, solder the correct AWG required for the RAMBo so you aren't monkeying with 4 yellows/blacks in that connector.... with that 15AMP blade fuse you would be OK with 18 gauge.

i was lazy and taped mine

[Captain Starfish]

Lazy? No.

Efficient.

[int2str]

I modified the existing ATX PSU as you have specified. Opened it up, removed all sorts of wires, cut off all connectors etc.

But then I took it a step further and bought a FULLY MODULAR power supply and simply only used the wires I needed.
Here's the result:
http://forum.seemecnc.com/download/file ... &mode=view

[Eaglezsoar]

All but the last step. Yes, it would be cleaner. But who cares about a mess you never see and that never gets in the way?

I personally grouped the redundant wires by colour (so shorting isn't an issue), taped the bundle ends to insulate, rolled 'em into a tight bundle and taped the bundle to hold it. These bundles all sit tucked up in the PSU bay where I don't have to think about them. So far, less work. And who ever goes into the PSU area ever anyway?

More advantageous is when it comes time to add (for example) the obligatory RAMBO driver fan. Tease out a ground and 5 or 12V line depending on your fan, solder a connector on and plug the fan in. PSU doesn't even need to come out of the base. Easy.

You know, those are some really good points. I tend to over-clean my projects; if doing so doesn't improve the results, and may prevent a future mod, then it probably ain't worth the effort.


Thanks,
Dan

I don't think you over cleaned your project at all. Removing all the wires you don't need makes for a much cleaner install. The idea of leaving a big wad of unused wires in there
because you don't see them is like having the attitude of sweeping the dirt under the rug, why not you don't see it anyway. Personally I think you did an excellent job!

[Captain Starfish]

Dunno about the dirt under the rug analogy, I like to think it more akin to the junk in the shed analogy.

"that will come in handy, one day".

By the time you add fans to the motherboard, LED rings to the bed AND extruder platform, separate PID controllers for the 4 other extruders, yada yada yada you'll be wanting those wires

[enggmaug]

I don't think you over cleaned your project at all. Removing all the wires you don't need makes for a much cleaner install. The idea of leaving a big wad of unused wires in there
because you don't see them is like having the attitude of sweeping the dirt under the rug, why not you don't see it anyway. Personally I think you did an excellent job!

If you don't sweep dirt under the rug, then what's the point of having a rug in the first place ???

[Eaglezsoar]

I don't think you over cleaned your project at all. Removing all the wires you don't need makes for a much cleaner install. The idea of leaving a big wad of unused wires in there
because you don't see them is like having the attitude of sweeping the dirt under the rug, why not you don't see it anyway. Personally I think you did an excellent job!

If you don't sweep dirt under the rug, then what's the point of having a rug in the first place ???

I'll have to think about that one and get back to you. That question is to deep to answer quickly.

[Captain Starfish]

I don't think you over cleaned your project at all. Removing all the wires you don't need makes for a much cleaner install. The idea of leaving a big wad of unused wires in there
because you don't see them is like having the attitude of sweeping the dirt under the rug, why not you don't see it anyway. Personally I think you did an excellent job!

If you don't sweep dirt under the rug, then what's the point of having a rug in the first place ???

[geneb]

The only problem that I see with hacking the power supply is some idiot that has NO business being inside that thing is going to see these posts and go, "Dah, hey! I can do that!" and then it's all over but the fire, screaming and the ER visit.

g.

[dtgriscom]

The only problem that I see with hacking the power supply is some idiot that has NO business being inside that thing is going to see these posts and go, "Dah, hey! I can do that!" and then it's all over but the fire, screaming and the ER visit.

... and the salivating lawyers...


In any case, tonight I'll do a blend of all of these:

• Leave the inside of my PSU alone
• Cut off all the connectors
• Take the needed four black and four yellow wires and, instead of twisting them together, solder them to 14-gauge stranded wires, which will in turn go into the RAMBo connector (should be a much better connection)
• Connect the other blacks and yellows to separate pins on the RAMBo connector
• Connect the green and black to the power switch
• Take all the unused wires and bundle them up by color.

Thanks for all the help,
Dan

[geneb]

14ga is overkill (and may not fit in the terminal block). 16ga would be just as good.

g.

[dtgriscom]

14ga is overkill (and may not fit in the terminal block). 16ga would be just as good.

Ultimachine reports that the RAMBo terminal block can handle 26-12 gauge wire. I'll use whatever I can find easily.

[Eaglezsoar]

14ga is overkill (and may not fit in the terminal block). 16ga would be just as good.

Ultimachine reports that the RAMBo terminal block can handle 26-12 gauge wire. I'll use whatever I can find easily.

Ultimachine needs to rewrite their specs, I have had a tough time getting 14 gauge wire in the terminal block. Maybe they are using solid
copper wire or drinking too much when they write specs.

[geneb]

He might be referring to the power block on the side - it is larger than the green one along the top.

g.

[Eric]

I can think of another good reason stay out of the dangerous box. The manufactuers warranty may be gone when you start cutting wires, but SeeMeCNC's warranty is still there, at least until you break the seal on the box. They are nice guys and might replace a premature failure anyway, but remember they've given you zero instructions to unseal that box.

[dtgriscom]

He might be referring to the power block on the side - it is larger than the green one along the top.

Yup: I'm talking about the removable 1x6 Euro terminal block. I just checked, and it does fit stranded 12 gauge wire. I'll take the 4-wire yellow and black bundles, solder them to single 12 gauge wires, and put those into the connector. Yes, it's overkill, but it reduces even further the chance of a bad connection and the terminals melting down.

[geneb]

The melted terminal blocks are usually linked to people tinning the end of the wire before they put it into the block. With the wire end full of solder, the terminal can no longer flatten the wire and give it adequate surface area contact. With too little surface contact, the resistance of the connection goes way up. High resistance works out to high temperatures....

g.

[turnermarke2]

If you have cut off all the "spare wires" off your power supply ckt bd you have disconnected the 3.3V remote sense (the small brown wire connected to a orange wire ). By the way is there a easy way to remove the power supply.
Thanks
Mark

[dtgriscom]

If you have cut off all the "spare wires" off your power supply ckt bd you have disconnected the 3.3V remote sense (the small brown wire connected to a orange wire ).

This isn't necessary for this power supply (it certainly isn't connected on mine, or on anyone's who has followed Gene's instructions). It may be required on some ATX supplies, but if so then I'm guessing SeeMeCNC selects supplies where this isn't true.

By the way is there a easy way to remove the power supply.

Good question: there is not. You'd have to take off the bottom of the printer.


Dan

[geneb]

Remove the four nylon screws from the power supply and push it back a bit. It will drop out of the hole in the bottom plate...like it was designed to.

g.

[Eaglezsoar]

Remove the four nylon screws from the power supply and push it back a bit. It will drop out of the hole in the bottom plate...like it was designed to.

g.

That would make a great addition to the manual when you don't have anything else to do.