[Solved] How Adjust Potentiometer?

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Ravitch
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[Solved] How Adjust Potentiometer?

Post by Ravitch » Thu Jan 12, 2017 8:16 pm

Here I am with my brand new multimeter. And lost. And search is failing me.

Trying to fix my hotend decoupled error, and unsure of how to test the right voltage or adjust on the power supply. Is there I guide out there for doing this on the Rostock Max V3?

Thanks!
Last edited by Ravitch on Fri Jan 13, 2017 3:31 am, edited 1 time in total.

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Xenocrates
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Re: How Adjust Potentiometer?

Post by Xenocrates » Thu Jan 12, 2017 8:24 pm

So, to find the voltage the supply is outputting, place the probes of the multimeter onto the V+ and V- terminals of the power supply (red to red, black to black, although if you mess up it should give you the same number, but with a negative in front). Then take a screwdriver, most likely phillips, and use it to turn the potentiometer on the power supply. Adjust the voltage until you see a fairly steady 12 (Possibly 12.6 or 12.8 if you need more heating performance). If it goes the wrong direction, turn the other way.
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Ravitch
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Re: How Adjust Potentiometer?

Post by Ravitch » Thu Jan 12, 2017 9:15 pm

Xenocrates wrote:So, to find the voltage the supply is outputting, place the probes of the multimeter onto the V+ and V- terminals of the power supply (red to red, black to black, although if you mess up it should give you the same number, but with a negative in front). Then take a screwdriver, most likely phillips, and use it to turn the potentiometer on the power supply. Adjust the voltage until you see a fairly steady 12 (Possibly 12.6 or 12.8 if you need more heating performance). If it goes the wrong direction, turn the other way.


Awesome, thank you soooooo much! Off to try it now, fingers crossed that I don't fry myself! ;). I'll report back with a sign of life and results.

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Re: How Adjust Potentiometer?

Post by Ravitch » Thu Jan 12, 2017 9:41 pm

Ahhhhh, it appears I may have bought too sissy of a multimeter. It's says not to test on D.C. Greater than 10A and the power supply sticker says 29.7A. Sorry I'm being such a pain with the questions, this is what getting raised by a single mom gets you, completely stupid on man tasks.

Attached pics of my wimpy multimeter to confirm or deny it's too wimpy for the task.
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Ravitch
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Re: How Adjust Potentiometer?

Post by Ravitch » Thu Jan 12, 2017 10:01 pm

Well, much like when I was an Artillery pull string go boom guy in the Army, I shrugged and used the multimeter. Nothing died and I was registering 12.11. I went ahead and cranked the juice up to 12.60. Time for a test print!

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Re: How Adjust Potentiometer?

Post by Eric » Thu Jan 12, 2017 10:33 pm

Ravitch wrote:Ahhhhh, it appears I may have bought too sissy of a multimeter. It's says not to test on D.C. Greater than 10A and the power supply sticker says 29.7A.


The 200 milliamp and 10 amp restrictions only apply when you're measuring current, not voltage. In addition to selecting the selector dial and hooking things up differently, to use the 10A scale you actually have to move the red probe over to the 10A socket. I'd suggest learning more about electricity before attempting to measure current...and start out with small battery circuits.

Your limit on measuring voltage is 600 volts. Not an issue in this case, and as you discovered, it worked fine.

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Re: How Adjust Potentiometer?

Post by Ravitch » Thu Jan 12, 2017 11:07 pm

I agree with you Eric, I definitely need to learn more. That's why I made my wife hold the multimeter to the power supply ;)

I totally figured out my "Hotend Decoupled" followed by the def showing up on the screen, and figured it out by accident. On the new Hotend, when the layer fans kick on at the second layer, they cause the Hotend to rapidly cook until it Hotend Decoupkes and shows Def. I can only turn the layer fans on to 50 percent without cooling the Hotend down to the point where it won't extrude.

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Re: How Adjust Potentiometer?

Post by Xenocrates » Fri Jan 13, 2017 12:21 am

As Eric says, don't worry about the "wimpy" amperage restrictions. He's entirely right about that, and even an industrial multimeter designed for 1KV is usually only going to have 10A of amperage sense. For larger amperages, either clamp on, or specialized equipment is usually a better bet. If you were to over-do the amperage (Such as by hooking an amperage test multimeter in parallel rather than series(IE, touching it to two parts of a live circuit rather than disconnecting the circuit and remaking connection through the MM)), you would likely only blow a fuse, and thankfully for cheap multimeters like that, the fuse is also cheap, unlike some with 20$ fuse sets.
Machines:
Rostock Max V2, Duet .8.5, PT100 enabled E3D V6 and volcano, Raymond style enclosure
Automation Technology 60W laser cutter/engraver
1m X-carve router

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Re: [Solved] How Adjust Potentiometer?

Post by rurwin » Sat Jan 21, 2017 7:45 am

When it's reading current a meter has to have a very low resistance. When it's reading a voltage it has to have a very high resistance. So a meter in volts mode is pretty safe to have an accident with such as by touching terminals you shouldn't be touching or accidentally grounding a probe on the chassis. (You can still short stuff out with a single probe of course.) If I'm reading current I try to have the meter firmly attached to the circuit before I switch the power on. I used to have a nice antique panel-mount amp-meter with the needle literally wrapped around the end-stop because it touched something it wasn't supposed to for a fraction of a second. No such problems with volts unless you try to measure mains on the 2V scale.

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