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Another opinion: The data from Tecknatool are interesting but as inferred, dangerous. The first PDF on vacuuming and gently blowing is good, but the second PDF shows pictures that do not resemble the fan area on the PowerPro. I therefore would not try to use any of the disassembly of the fan on the PowerPro at all.

The PowerPro has a large black plastic cover over the fan. In the past I have been instructed by Shopsmith to remove this cover and blow out the area beneath. This was done by removing the four motor mount screws closest to the spindle and only loosening the two screws closest to the belt. Now the motor can be pivoted (like adjusting the belts) and the plastic black fan cover can be removed.

I totally agree with charlese.

As I said; "again do not follow the second one without Shopsmiths direct instruction or you could void your warranty."

They are one of those 'same thing, only different' items we often hear about.

They do the same work, with the same function, but different bits and pieces.

It was the knowledge transfer of what might be causal for the effects you are seeing that I was getting at.

The info in the second PDF may be useful, but certainly not directional on the Power Pro version.

Everett

Everett,
Thanks for the tech info! I'm a EE, and familiar with both brushless DC motors and steppers, so I have som familiarity with how DVR motors work.
As a matter of personal and professional curiosity, I'm trying to diagnose the problem myself first rather than just send the whole package back for repair or replacement under warranty.

After some experimenting, I've discovered that the Error 0 shutdown happens independent of load on the motor. It also doesn't appear to be related to transients in the electrical mains, such as the A/C ciompressor kicking on. I'm running it with no load at 900RPM as I write this, to see if the failure occurs at lower speeds over time, too. I've cleaned the sensors, and under these no-load test conditions, I'm not generating or moving any dust.

I've reseated the ribbon (i.e. sensor signal) and power cable connectors between the motor controller and motor, to no effect. I haven't touched the cables to the HMI yet because I would need to remove the controller as well as motor to get to it, but did visually examine all cables for pinching and insulation breaks. The ribbon cable ends are staked with some sort of sealant/adhesive, so it would be tough to check for improper pin or socket seating without removing the staking material.

The HMI firmware rev is 908CSA16 2011, so it's not likely a result of a firmware bug, because I've had hundreds if not thousands of PowerPro owners before me as beta testers . If I had to guess, I'd say there is a poor solder joint in the Vcc or GND circuit to the sensor board. It could also be a poorly plated via on a PCB, poor crimp in connector, or maybe a broken conductor inside the insulation of one of the wires. Any of those could have passed QC testing, but fail randomly under vibration, or under mechanical stress from thermal expansion. If the unit was out of warranty, I'd be wiring test leads into the sensor board to diagnose the problem.

Transient failure analysis can be frustrating, but it's rewarding to finally stamp out that annoying bug once and for all, especially when the source of the problem isn't where you thought it would be and you have to go through some serious detective work to find it.

Ok, here is the results of the latest experiment. I ran the unit for 40 minutes at 900RPM with no load, and there were no failures. Immediately after shutting it down, I restarted it at 2000RPM and let it run for 10 minutes, again with no failures. I was too tempted by the running tool, so I finished more staircase spindles using the jointer. After roughly a half hour, it failed, but not as suddenly as at the 3450 RPM it had been failing at before.

This time the failure was surging, dropping RPMs and returning to 2000, for ~4 seconds. There were no error messages, although the RPM display did reflect the drops in speed. After the 4 seconds, it quit entirely, with the standard Error 0 message. I'll drop by the unit every 10 minutes to see how long it takes before it will accept a restart.

Shug wrote:Ok, here is the results of the latest experiment. I ran the unit for 40 minutes at 900RPM with no load, and there were no failures. Immediately after shutting it down, I restarted it at 2000RPM and let it run for 10 minutes, again with no failures. I was too tempted by the running tool, so I finished more staircase spindles using the jointer. After roughly a half hour, it failed, but not as suddenly as at the 3450 RPM it had been failing at before.

This time the failure was surging, dropping RPMs and returning to 2000, for ~4 seconds. There were no error messages, although the RPM display did reflect the drops in speed. After the 4 seconds, it quit entirely, with the standard Error 0 message. I'll drop by the unit every 10 minutes to see how long it takes before it will accept a restart.

I so wish I could be there in your shop with you. This is the sort of testing that I did for years and I miss the challenges. Step by painful step with no assumptions. Just factual data recording until a conclusion can be reached (based on that data).

I hope you can get this resolved shortly. I will be watching for every post.

Shug wrote:Ok, here is the results of the latest experiment. I ran the unit for 40 minutes at 900RPM with no load, and there were no failures. Immediately after shutting it down, I restarted it at 2000RPM and let it run for 10 minutes, again with no failures. I was too tempted by the running tool, so I finished more staircase spindles using the jointer. After roughly a half hour, it failed, but not as suddenly as at the 3450 RPM it had been failing at before.

This time the failure was surging, dropping RPMs and returning to 2000, for ~4 seconds. There were no error messages, although the RPM display did reflect the drops in speed. After the 4 seconds, it quit entirely, with the standard Error 0 message. I'll drop by the unit every 10 minutes to see how long it takes before it will accept a restart.

IMHO, it is time to call the MS on Monday asked to talk to some one in Eng on this, give them your credentials as an EE, what you have done and what you surmise, and have a heart to heart talk with them.

Cold Solder joint or cracked land.

That's my guess.

Shug
As a former electronic troubleshooter (2 way radio systems) and also working for a major company in the reliability department I really want to know what the resolution proves to be.
Two statements stood out when i read the Teknatool PDF's. The first is:

RPS State Error relates directly to the sensor

This seems to state that this problem can only be attributed to the sensor board. All cables have at least two ends and the problem can be at either end. They only seem to focus attention on one end.

The second one is

Now make sure that the cord connecting to the sensors must have no slack, pull it down to the lower control board area to make sure the position disc doesn't catch it.

Apparently they have had some occasions where that cable had some conflict with the position disc which may be why that warning is there. I would be inclined to look there first.

I have always had a love/hate relationship with intermittents. Hated them because they were so elusive but also loved them for what they taught me.
Please post the root cause when you solve it
Bill V

Shug wrote:Everett,
...
As a matter of personal and professional curiosity, I'm trying to diagnose the problem myself first rather than just send the whole package back for repair or replacement under warranty.
...
Transient failure analysis can be frustrating, but it's rewarding to finally stamp out that annoying bug once and for all, especially when the source of the problem isn't where you thought it would be and you have to go through some serious detective work to find it.

Shug,

You're preaching to choir with those statements! This forum is filled with problem solvers who feel the same way, each of whom would love to be there with you to discover what is throwing that error. I agree, with your credentials, the call needs to be escalated to a technical engineer with whom you can map a course to discovery, if they are capable of allowing that level of dialog to occur under contracts.

Your additional comments reveal the level of diagnostics and observation employed in your discovery mission are extensive.

If you cannot diagnose further based on policy, I would hope that they can provide you a detailed analysis of their failure analysis of your system.

Ideally, they have someone at Teknatool who has some history with these sorts of errors that can with a high degree of accuracy, remotely diagnose the problem.

Shopsmith has had a loaner headstock program in place for years where they will ship you a headstock to use in production while they effect repairs on yours.

I know inquiring minds want to know what it was when you find out.

Everett

JPG
I would lean that way too. But the surging suggests that the failure may be an error in the system reading the output from the sensor. Possibly very light contact between the position disc and the sensor cable. But that could be a WAG. A wag is a military term meaning a Wild A-- Guess. But I think you already know that!!!
Bill V