RTS 400 Running slow?

[Joe Jensen]

My RTS400 seemed to be running slow.  I checked the speed control and it was on 6.  When I adjusted it to 1, the motor won't even spin.  Time to figure out how to service a Festool.  Hope it's not gone too long.

 

[Rick Christopherson]

The obvious answer is that you need to have the tool sent in for service, regardless whether it is under warranty or not. The only cause for reduced speed that I can think of is a failure in one of the output transistors on the PWM module. This is not user serviceable, except that the entire module could be replaced.

 

[spikfot]

The obvious answer is that you need to have the tool sent in for service, regardless whether it is under warranty or not. The only cause for reduced speed that I can think of is a failure in one of the output transistors on the PWM module. This is not user serviceable, except that the entire module could be replaced.

Rick,
In the spirit of being helpful and responding kindly to a question, the first sentence above serves no real purpose.

Joe,
It is easier to answer technical questions if you state where you are on the planet, or at least offer what voltage you are operating on.
There could be a number of faults that create the problem you describe, And yes, I own the sander in question.

 

[Rick Christopherson]

Rick,
In the spirit of being helpful and responding kindly to a question, the first sentence above serves no real purpose.

You misread the intent of my posting. I was not being condescending, which I suspect you thought I was. So let me restate my answer, and see if you don't view it differently this time.

"Given the symptoms described by the OP, this is not a user-repairable problem, so obviously it must be returned for service."

There was no ill intent. You cannot replace the output transistors on the PWM board.

==========================================
Edit: Actually, your posting was a good thing, because it made me reread everything a couple more times, and it occurred to me that a dirty wiper in the variable resistor speed control might also cause the symptoms.

So before giving up and sending the tool in for service, with the tool running, constantly move the speed control back and forth from 1 to 6 and see if performance changes at all. If you see erratic changes (sudden leaps in speed) but the problem still persists, then the dial assembly needs replacement. However, exercising the dial like this could also clean the wiper, in which case full performance could be restored, and no repair would be necessary.

However, if doing this results in no change whatsoever, then my original diagnosis is probably correct and the PWM module needs replacement.

 

[Joe Jensen]

I'm in Arizona running on 110V.  Planning to send it in unless there is something like the brake broken or out of position that could cause this. But since it's under warranty I'll send it it.  Seems to be running full speed on setting 6, but it's hard to tell.

 

[Wood_Junkie]

So before giving up and sending the tool in for service, with the tool running, constantly move the speed control back and forth from 1 to 6 and see if performance changes at all. If you see erratic changes (sudden leaps in speed) but the problem still persists, then the dial assembly needs replacement. However, exercising the dial like this could also clean the wiper, in which case full performance could be restored, and no repair would be necessary.

However, if doing this results in no change whatsoever, then my original diagnosis is probably correct and the PWM module needs replacement.

THANKS RICK for posting this.  I am having a similar problem with my ES150/5 running only at full speed.  I'll try this tonight and cross my fingers.  The previous owner said he never changed speeds.  "Got best results at full speed".  So perhaps it's just a dirty/sticky thing.

 

[Rick Christopherson]

THANKS RICK for posting this.  I am having a similar problem with my ES150/5 running only at full speed.  I'll try this tonight and cross my fingers.  The previous owner said he never changed speeds.  "Got best results at full speed".  So perhaps it's just a dirty/sticky thing.

Yes, with those symptoms, it is the variable resistor that is not working. Furthermore, given that the previous owner did not change speeds very often, it is also very, very likely that you can restore full functionality by exercising the dial.

Edit: Hmmm, there might be another possibility, but I would have to see a schematic of the PWM module to know for sure if this is possible. My initial thought would be that if the variable resistor was disconnected, the motor would not run at all, but if there is an internal bias resistor on the PWM module, then unplugging the speed control would have the same symptoms.

If it is no longer under warranty and the steps above do not result in ANY change in speed, then you might consider opening the case and see if the speed control came unplugged from the PWM module. As a matter of fact, exercising that little white plug (reconnecting it several times) could also restore a bad connection. Just be careful not to bend the pins on the receptacle of the PWM module.

 

[spikfot]

I'm in Arizona running on 110V.  Planning to send it in unless there is something like the brake broken or out of position that could cause this. But since it's under warranty I'll send it it.  Seems to be running full speed on setting 6, but it's hard to tell.

Under warranty? --- best to check first before enlisting the help of the peanut gallery.
But, when all else fails, we're here (for better or worse)
Ride the yule tide,
Bill

 

[bobbobbob]

THANKS RICK for posting this.  I am having a similar problem with my ES150/5 running only at full speed.  I'll try this tonight and cross my fingers.  The previous owner said he never changed speeds.  "Got best results at full speed".  So perhaps it's just a dirty/sticky thing.

I recently sent my ETS 150/3 in for this same problem.  They replaced the entire module.  I too, looked at the connections and they were fine.  My pot for the speed control had no physical resistance so that was a clue there.  Good luck!

 

[Joe Jensen]

I traveled the last 7 days and stupidly forgot to send it in before leaving  [mad]

Will send it in tomorrow.

 

[projectboats]

Mine has similar symptoms. Any idea what the module replacement costs?? They seem to have the market cornered for repairs.