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Author Topic: yet another RTS400 not working  (Read 318 times)

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Offline imaginarynumber

  • Posts: 71
yet another RTS400 not working
« on: October 27, 2019, 03:16 AM »
My first RTS400 was largely unloved by me when I specialised in painting MDF units. I would guestimate that over a 4 year period it would have been used for 30 hours.

One day, I needed to use it sand a customers walls. Both of my Rotex devices were elsewhere at the time.

I was using the RTS and noticed the speed kept fluctuating wildly- it would drop from full speed to the lowest and then back up to full speed. After a day or two it eventually just started humming loudly and the sanding base was almost static.

I tried to dismantle it but I could not remove the screw that holds the crescent shaped brass plate that enables the oscillating of the base plate. Frustrated, I binned the sander.

Roll forward a few years and I needed another RTS400. after about 10 months the same thing happened. I sent it back for in warranty repairs. It was fixed. I used it for a few months, all was good. Again, I didn't use it again for ages and when i needed it, the same thing happened after a few weeks.

I own several Festool products, other than the RTS and the plastic teeth used in the old Rotex 150, I have never had any complaints about build quality.

I take it that I am not the only person that has experienced this fault. Does anyone know if the problem is related to the speed control PCB or the bearings?

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Offline Alex

  • Posts: 6191
Re: yet another RTS400 not working
« Reply #1 on: October 27, 2019, 07:29 AM »
Does anyone know if the problem is related to the speed control PCB or the bearings?

I've been using the DTS and RTS en ETS 125 for years now and I have never experienced any problem except for the Plug-It cord failing. If the cord or plug is broken it can cause the symptoms you discribe.

When Festool fixed your RTS, didn't they tell you what it was they exactly fixed?

Speed control units do tend to fail once in so many cases. It is a small percentage, but it is one of those parts that fail quicker than others because it is more complicated.

Offline imaginarynumber

  • Posts: 71
Re: yet another RTS400 not working
« Reply #2 on: October 28, 2019, 08:20 AM »


I've been using the DTS and RTS en ETS 125 for years now and I have never experienced any problem except for the Plug-It cord failing. If the cord or plug is broken it can cause the symptoms you discribe.

When Festool fixed your RTS, didn't they tell you what it was they exactly fixed?

Speed control units do tend to fail once in so many cases. It is a small percentage, but it is one of those parts that fail quicker than others because it is more complicated.

Thanks for the reply Alex.

I have tried other PlugIt leads and the pins seem to be free of charcoal deposits.

Perhaps I should contact Festool and give them the serial number to find out what they did to fix it last time.

I have no idea why I have been so unlucky with the RTS. My oldest Festo tool (DX93) was purchased in the late 90's and is still going strong (after replacing the odd component here and there).