Shopsmith Forums

I have Mark7 I bought in 2015. Everything seems to work fine. But when I am turning a large bowl I sometimes get a low voltage error on the display. So far I can't see that it has hurt anything.
I'm beginning to wonder if it really is low incoming voltage. Seems to happen under a load. Maybe under a load I'm drawing too much current which is dropping the line voltage?
Has anyone else had this problem? Or know the answer?

You could try plugging in a voltage meter in the outlet with the Shopsmith to see if it shows a voltage drop. A plug in meter can be found at most RV supply stores. Do you use an extension cord to plug in your Shopsmith? If it is under size/rated for the power needs of the Shopsmith that could be the problem.

I don't know if this helps you, but this is from the Mark 7 Troubleshooting Manual. How hot is the headstock when this happens? Also, Russ' suggestion for checking line voltage is a good one.

Well I move to another power source. This time I'm using one leg of a dedicated 220 outlet with #10 wire. Still same issue. Still getting a "lowv" on the top line, to the right of the speed selected, when under a load.
This time I'm turning a 14" bowl @ 700 rpm. I'm probably taking off too much wood at one time.
I guess I should be looking for a dedicated lathe for the larger stuff. Just hate to spend the money.

rdgrnstd wrote:Well I move to another power source. This time I'm using one leg of a dedicated 220 outlet with #10 wire. Still same issue. Still getting a "lowv" on the top line, to the right of the speed selected, when under a load.
This time I'm turning a 14" bowl @ 700 rpm. I'm probably taking off too much wood at one time.
I guess I should be looking for a dedicated lathe for the larger stuff. Just hate to spend the money.

Did you happen to see my post or the Mark 7 Troubleshooting document that I posted? Turning a 14" bowl, my guess is the headstock is getting overheated. How hot to the touch does the headstock feel when this happens?

I saw the Mark 7 Troubleshooting document you posted. Thanks for posting it.
I have overheated it before. But It doesn't seem to have to get hot for the low voltage to show up.
I'm still probably overheating, just noticing the error before I can really feel the heat.
Like I said before everything seems to still work and it doesn't come on all of the time just when I put it under a heavy load for a while.

I also have a noise even when turning the quill shaft by hand. have to make two revolutions of the quill shaft to make the noise. So it is probably coming from the motor. I'll have to take it apart again.
I just had to tighten the pulley on the motor and I replaced the motor positioning disc because it was cracked and loose.

Thanks for all of the comments, Guys.
By the way I still love my Mark 7. My dad gave me my first one (Mark V) in 1981. When I retired I gave it to my grandson and bought a new Mark 7. Using it nearly every day now.

rdgrnstd wrote:I saw the Mark 7 Troubleshooting document you posted. Thanks for posting it.
I have overheated it before. But It doesn't seem to have to get hot for the low voltage to show up.
I'm still probably overheating, just noticing the error before I can really feel the heat.
Like I said before everything seems to still work and it doesn't come on all of the time just when I put it under a heavy load for a while.

I also have a noise even when turning the quill shaft by hand. have to make two revolutions of the quill shaft to make the noise. So it is probably coming from the motor. I'll have to take it apart again.
I just had to tighten the pulley on the motor and I replaced the motor positioning disc because it was cracked and loose.

Thanks for all of the comments, Guys.
By the way I still love my Mark 7. My dad gave me my first one (Mark V) in 1981. When I retired I gave it to my grandson and bought a new Mark 7. Using it nearly every day now.

I don't know how comfortable you are with modifying your PowerPro, but I have heard of more owners doing this solution to solve the overheating issue. IF you have access to Facebook, you might want to check out these posts related to adding a fan and small HEPA filter to your PowerPro. Supposedly, if done properly it both cuts down on the overheating issues AND solves the dust inside issues that cause the motor stator position error. I believe the first solution is kind of a bolt on fan solution that connects to the access on the back of the PowerPro, so no modification to headstock. He has a new and improved solution (2nd link) but I don't know how it attaches to the PowerPro headstock, i.e. it may require further modifications. Sorry to post Facebook links here, but I really haven't seen much discussion of an overheating solution on this forum. If I missed a past thread from this forum, maybe someone else can post it here to help. For the noise, I don't know if this helps, but there was a recent discussion on PowerPro noise. Check out the Shopsmith forum link below for that thread regarding noise. I hope this helps:

https://www.facebook.com/groups/6844615 ... 183947526/

https://www.facebook.com/groups/6844615 ... 036479168/

https://www.shopsmith.com/ss_forum/view ... se#p266154

Guess I'll have to join Facebook to see what someone else has done. I have no problem modifying it.
I've thought about an external fan but haven't got serious about it. I still need to open it up and check for the noise.

rdgrnstd wrote:Guess I'll have to join Facebook to see what someone else has done. I have no problem modifying it.
I've thought about an external fan but haven't got serious about it. I still need to open it up and check for the noise.

I am no expert on it (since I don't own a PowerPro) and this is just what I read online, but the idea with this kind of solution is it keeps the PowerPro cooler. I think I saw 10 degrees cooler posted somewhere. Supposedly, the clean air getting pumped in from this HEPA filter causes a positive air displacement inside the PowerPro headstock, i.e. always air going from inside to outside through any cracks and openings. By creating a positive air displacement, in theory, no dust would ever enter the PowerPro headstock, so it cuts down on the stator position sensor errors that creep up from dust infiltration into the headstock.
[youtube]https://www.youtube.com/watch?v=USWBJjkQQGI[/youtube]

Well, I think the noise is coming from a loose aluminum pulley on the motor. or at least the slapping noise.
I tightened it about a week ago and put loctite on the set screw, but loose again and still has a rocking motion.
I thought about shimming it but think since it rocks I might as well get a new one.
I replaced the idler shaft assembly in 2019 making a lot of roaring noise.