grounding cable?

[SouthShoreDecal 0]

I know that grounding cables/three prong plug grounding is a common topic and cause for some problems. 

Where on the machine should a cable be attached to ground the cutter to the stand?

[YadirellT 0]

Hi.  The instruction for that basically says: "make sure you connect the black ground wire to the bottom of the cutter, and then to the stand. You should see where it connects to the bottom of the cutter, and you can loosen any screw on the stand to connect. The ground wire comes in the box with the other cables, blades, etc."

You can find a lot of answers for setting up your cutter at support.uscutter.com

[SouthShoreDecal 0]

i do not remember seeing a cable in the box, but i will recheck when i get home. 

thank you

[Dakotagrafx 7,297]

the wire mentioned I think only ships with the refine mh series

[BannerJohn 1,324]

any bit of wire will do.

[Dakotagrafx 7,297]

Oh yeh - John is right I forgot to mention it is just a thin wire with lugs on the ends.  guess that was kinda imoportant

[SouthShoreDecal 0]

I checked what came with my cutter, it is a mh721, and i did not receive a ground wire.  This is no problem.  what screw do  i attach the wire to on the unit and where on the stand?  i assume anywhere on the stand that i can get bare metal. 

[Dakotagrafx 7,297]

yeh any screws on the bottom of cutter will work and same for stand

[SouthShoreDecal 0]

fair enough, i will make the cable tomorrow and install it.

thank you for the quick replies! 

[Dakotagrafx 7,297]

oh - we love to help

[muddywaterpirate 1]

I love to get help, being a total noob!

If the machine is grounded through the three prong plug, why does it need to be grounded with a wire to the stand?  What I was thinking is, the stand is grounded because it's just a metal stand on wheels not grounded to anything itself, so how would putting a wire on the stand ground the cutter?

[Dakotagrafx 7,297]

working with vinyl all parts can collect static electricity - you are actually grounding the stand to the cutter so a build up doesn't find its way to the cutter and fry the electronics

[muddywaterpirate 1]

working with vinyl all parts can collect static electricity - you are actually grounding the stand to the cutter so a build up doesn't find its way to the cutter and fry the electronics

Which was apparently what happened before.  I just installed a new motherboard because the old one would lift the blade holder.  The machine worked, but the blade holder wouldn't lift.  After installing the new motherboard, I grounded the machine to the stand like suggested to be on the safe side.  I just didn't understand why.  Thanks!

[Dakotagrafx 7,297]

I actually made an extra ground wire that goes from a ground to the stand just to be safe

[jd_design 0]

The motherboard on my MH-871 was zapped the first time I tried using it while on the stand. I found out the hard way it's not a good idea to pull new vinyl off the roll, load it into the machine, and attempt cutting without a having a ground wire hooked up! Not only that, my stand was sitting on carpet which is also a no no (the wheels are now sitting on some ceramic tiles). I did get a new motherboard and while waiting for it to arrive, had some time to figure out a way to ground the cutting blade itself.

The metal feed rollers are grounded to the chassis of the unit (but never really touch the vinyl). The carriage however, doesn't seem to be grounded. I figured if static is built up on the face of the vinyl, the cutting blade could possibly send it through to the circuitry inside. Which doesn't make sense, since the blade holder isn't really connected to any metal. It shouldn't be able to arc all the way into the carriage unit, then down to the motherboard.

All I know is, after I put my machine on what was the ungrounded stand, I loaded the vinyl, clicked "cut" and when I turned to look at the machine as soon as the blade hit the surface of the vinyl I saw a blue flash/spark down near the bottom right side of the unit. That's when the motherboard was zapped, the LCD screen when black and the carriage would no longer lift.

So I did a crazy mod on my machine and hooked up a ground for the blade holder. It goes from the blade holder up to the top of the carriage unit, hooks to the piece of metal measuring tape (what a great cost saving design), then a jumper wire from the screw on the other side of metal tape to a chassis ground. That's the only way I could get a good ground all the way back to the chassis due to the movement of the carriage. I used a multimeter and tested continuity, the tip of the blade is now grounded.

Maybe I'm being paranoid about static. I just don't want to spend $80 on another motherboard down the road! I've ran about 50 yards of vinyl so far with no problems.

First pic is the blade holder ground wire, the other is the stand to chassis ground.

[Peachykeen 0]

Does it matter what gauge the wire is?  Will antenna wire or speaker wire work?

Thanks!

[jd_design 0]

I would say 12 to 16 ga. wire would be fine. I think speaker or antenne wire would work. It doesn't have to conduct a lot of amperage, just high voltage to discharge the static.

[insanevinyls 0]

Mine didn't even come with a grounding cable so I created one of my own like many others have done so.

[rrc1962 0]

Ideally, you want to ground the roll of vinyl, since that's where the static comes from.  On my last machine, I wrapped the support rollers with metal tape then ran a ground wire to the rollers.  I grounded the stand to the machine and the rollers to the stand.  Check with an ohm meter to make sure you have good contact between the rollers and the frame.  I can't say this is THE solution, but I never blew a mother board in two years of borderline abuse.

Grounding the knife would also work but keep in mind that static could dissipate through the feed rollers as well and if those feed rollers are not grounded, that could also take out the motherboard.  I suspect the feed rollers are not grounded, otherwise there wouldn't be grounding issue as static in the vinyl would dissipate to ground that way...Unless the backing acts as an insulator.  I think dissipating any static before the vinyl even gets to machine is the best way to go.

[XENGINEGUY 0]

    Hi Everyone!  I am a completely new to sign making and vinyl cutting. I have had many gremlin problems with my new mh 871. Cutting to deep, crashing or locking signblazer  etc.  I would like to thank everyone on the forum for posting "fixes" for many of these problems... My gremlins were solved by adding a ground wire from the stand, to a face plate screw on a near by light switch! I installed a longer screw with a nut and washer(makes the screw stick out away from the face plate a little). The end of my ground cable has a alligator clamp to grab the screw.  (I also run a separate wire from the cutter to the stand.)  Face plate screws go directly to the house "ground", anyway it worked for me.

[Guest HowardI]

JD:  That is an awesome mod!

For all who ask about this, you really are grounding the stand to the cutter, since the cutter is grounded thru the power cord.

The feed rollers are indeed grounded, this is done inside the machine.

And you are all coming up with some great ideas!  Keep up all the great work!

Howard Irwin

Support Specialist

US Cutter

425-481-3555

888-298-8143

  - Option 2

[Michelaua 0]

i will try at home.. thanks for those pictures.

[tomadies 0]

I have the ground wire in place just as everyone suggests, and I still lost another z axis chip.  I'm getting extremely frustrated with this cutter.  I don't understand what the issue is, it has worked without a hitch for 6 months and now all of a sudden there are issues. 

I was curious if the motherboard in these units has standoffs like in a computer or not.  Is that where the issue is with static getting to it, or is it coming through the wiring?  I forgot to look when I had it open when I was replacing the last z axis chip to see if it was insulated from the chassis.

[tomadies 0]

Anyone want to buy a US Cutter MH 721 in need of a Z Axis Chip?  Real cheap!  I just pulled the trigger and bought a Graphtec Craft Robo Pro and no longer need this machine.  Make me an offer, tomdavis@bresnan.net

[MZ SKEETER 4,708]

Anyone want to buy a US Cutter MH 721 in need of a Z Axis Chip?  Real cheap!  I just pulled the trigger and bought a Graphtec Craft Robo Pro and no longer need this machine.  Make me an offer, tomdavis@bresnan.net

put it up in BUY SELL TRADE section.  not here...