Festool KS 120 fried, overvoltage

[Amon Amarth]

Well, hello forum. This one you may not have heard before: Due to an electrical issue I ended up with overvoltage in my shop momentarily. That means that instead of 230V in the sockets I had 400V for a few seconds. My Kapex was not running at the moment but it was connected and I could see a flash behind the handle and hear a little pop. Everything else in the shop is fine but the Kapex is of course stone dead now, no laser, nothing.

Apparently I hadn’t read the fine print and registered the machine so it has no warranty. I can send it out for a quote on nepair. Just curious though, maybe some people here are familiar with the electrical innards of these saws. What may have happened? Are there fuses of any kind inside? If the quote is too high so it’s not worth repairing, how are the prices on spare circuit boards and stuff? I have done some electronics repair and can handle the fiddly stuff pretty well. Spontaneously I want to think a capacitor might have blown from overcharging by 400 volts, what do you think might happen when a non-runnng saw gets blasted with more voltage than it is supposed to handle?

 

[Tinker]

I use surge protectors for all my electronic devices. It might be a bd idea to use them in the shop as well. I don't knowwhtelse one might do.
Tinker

 

[Cheese]

Interestingly enough, last summer the ground wire from the electrical pole got disconnected because of a tree branch rubbing against it. There was an ongoing voltage swing from 50 to 200 volts throughout the entire house. The Festool charger for the CXS and the charger for the C 15 both went up in smoke. Neither one was charging a battery, both were just plugged into the service.

Luckily for me, the Kapex was plugged in but unaffected. None of the other manufacturers chargers or tools had an issue of any kind.

I believe you don't need to register the tool for Festool warranty service to apply. Last year I had a Syslite that I never registered. I called Festool service, gave them the serial number, they verified it was under warranty and they issued me a shipping label for free shipping. I received the Syslite back 6-7 days later with no charges. I'd give Festool service a call.

 

[ChuckM]

Except for lights, no machines in my shop are hooked to a live outlet when they are not used. A few are plugged in a power bar and the bar is turned off unless the machines are used.

I, too, think that you may be eligible for any warranty service even if you did not register the saw.

 

[RKA]

In the US they don't require registration to obtain warranty service.  They do require proof of purchase or they will use the build date on the tool as the start date of the warranty if you don't have a receipt.  Your location might be different, but I would at least call and ask. 

That said, they may or may not cover this specific issue.  It depends on their goodwill, understandably.  If they won't, I would price out the board, open up yours and see if that's something you're comfortable replacing yourself.  In the US (and probably where you are), if you send it in and don't like the quote, they will send it back to you disassembled, which may leave you worse off than you started.  At least if you took it apart, you'll know how it goes together.  Hopefully it's just the smoked board that needs replacing, but you're taking a gamble.  This saw is not like most other miter saws, much more in the way of electronics, none of which I'm knowledgable about. 

 

[Sparktrician]

My shop has a whole-house surge protector.  It has served me well in general.  The down-side is that it doesn't work for Ethernet connections via the Verizon ONT.  A lightning strike a few years ago fried most of my Ethernet-connected goodies.  The surge came in via the ground wire from the distribution point to the ONT.  Unfortunately, the installer didn't common the ONT's ground point with cold water ground, so the surge got by.  I've since added an Ethernet surge protector and all is well on the banks of the Little Stinky Creek.  I concur with ChuckM in keeping tools disconnected when not in use.

 

[DeformedTree]

I assume you are in Europe based on the voltage, and simply can't believe they don't have warranty laws better than the US. So as was mentioned, you don't have to register for a warranty ever. In the US it the law.  "registering" is just a Data mining tool by companies and the businesses they work with to run registration programs. In short, never register for a warranty.

So Festool should be able to fix your tool.  I don't know where over voltage falls in their coverage. If this was an over-voltage from the grid, then the Utility could be liable for it. If something went wrong in shop, your home owners could come into play.  I would think Festool would be willing to help as long as you can explain it wasn't the your fault (you did something very un-smart).

Far as what could fail, any number of things, it will find the first weekest link, could be any number of things where the dialectic broke down first, so you might find yourself chasing parts for a bit.

 

[six-point socket II]

Hi!

Please don't forget that different countries have different laws.

Speaking for Germany there is:

"Gewaehrleistung" (one type of warranty) it's based on law(s) and must not be limited/restricted or otherwise tied to (additional) terms/conditions/requirements other than those set out by the law(s).

then there is:

"Garantie" (another type of warranty, maybe the better translation for this is "guarantee") it's based on whatever the manufacturer/seller sets out in terms/conditions or requirements. If you have not met/ If you do not meet the terms/conditions/requirements you have no base to claim anything.

Kind regards,
Oliver

 

[peter halle]

Sorry to hear about your issue.  I would suggest that you contact Festool Sweden or Festool in your country of origin via telephone and once again inquire about the warranty situation.  If they deny warranty coverage ask them to provide that to you in writing so that you can investigate other avenues as has been suggested here.  Filing a claim with a possible insurance carrier would certainly be the easiest route and then they can attempt remediation with other.

Peter

 

[Amon Amarth]

Well, hi again and thanks for all the replies. Apparently the "all-inclusive" warranty is only valid if the tool is immediately registered and as for a "basic" warranty, I find no information. Apart from what is required by law such as 30 days trial period for online purchases (in Sweden) I guess warranty is simply up to the manufacturer. Plenty of stuff you buy has no warranty at all. I guess Festool is perfectly within their right to place such conditions on their warranty schemes and not clearly phrase "if you do NOT register you are on your own, brother!". Such registration stuff normally contains nothing of real value so I just automatically toss it aside without reading it, so that is on me.

And dealing with insurance companies is about my least favourite thing to do, so I can't bring myself to that unless it's a house or a car... I have decided to dive into the machine myself and try to identify and replace the blown parts. USUALLY with stuff like this, I can get it done if I am stubborn enough. Which brings me to a follow-up question:

Normally with just about anything you can find excellent guides online on disassembly and repair on sites like Ifixit and such and there are also tons of useful videos on youtube but I have so far found very little on this saw. Does anybody have a good resource or some links that can be useful to me? I have started but just like with an Apple Iphone it feels like a Festool product is not designed to be easy to fix yourself...

 

[peter halle]

Disclaimer:  Personally I would not recommend that anyone attempts to repair their Festool Kapex on their own.  There are special tools and skills used by Festool when they make repairs.  Attempt to do so at your own risk.  I know that Festool does receive Kapex and other tools in boxes for repairs where the box is full of parts because of failed attempts to repair.  The repair costs for those tools may be higher than if the tool was sent in completely assembled.

That being said, here is a document that might help you figure out how to get the Kapex apart for examination or an attempt to repair yourself.  I only offer this whereas to the best of my knowledge it has been allowed to remain on the forum.

Peter

 

[Amon Amarth]

Thank you for that guide, it was helpful. So I did split the cover and saw nothing out of the ordinary (i wanted to check that first since I thought that was what threw a little spark when it happened). I then proceeded to pull the motor cover and remove the main PCB, or the first control board that gets mains power. I included a picture and from visual inspection it seems a resistor and a coated varistor has taken a beating... Now it would be kinda fun to replace those and maybe some more parts to see if I could bring it back to life but as you can see the circuit board is soaked in black resin which makes the board quite sturdy and resistant to various damage and also protects against DIY repair or reverse engineering. So I will simply have to find this board in the parts catalogue and replace it. I think it is very possible that the damage is isolated to this board.

I will post back with updates, thanks for your replies so far.

 

[Amon Amarth]

OK, so the new circuit board took its time to arrive, enough time for the holiday to take place. But now I am back and am piecing the Kapex back together from a faded memory (I took plenty of pics of the electrical connections but not enough of everything else) and at least the laser works... I reassembled the two shells with a couple screws and hooked it up, tried to run the saw but it would just hum. I disassembled it again and made sure the metal plate that holds the motor when the "smart stop" function (or whatever it is called, the knob for quick blade change) is not in the down position. I expected a DIY repair on a Festool device to be pretty miserable so that's all good. The blade will still not spin, it hums like something is holding onto it. When I pull the cord and move it by hand it spins and so does the motor but it does so in clicks, like one tooth at a time and it is quite heavy to move. I have not touched the motor itself but only replaced the main circuit board and the cables are back where they were before. What may be the fault? Do I have fried electronics past the main circuit board or have I forgotten something like a moron?

Feel free to roast me if I missed something obvious, I can take it and it also helps me learn.

 

[ChuckM]

Snip.
Feel free to roast me if I missed something obvious, I can take it and it also helps me learn.

I can't help you, but I like your attitude. [thumbs up]

I hope you can get it fixed and make it work again.

 

[harry_]

When I pull the cord and move it by hand it spins and so does the motor but it does so in clicks, like one tooth at a time and it is quite heavy to move.

I believe this to be normal. By hand mine has a stiff rotation and feels like there is detents.

 

[jonnyrocket]

Too bad about your saw. And sorry that the first board didn’t fix it. I will say that I don’t have any experience with fixing a Kapex, but in general when motors hum and don’t start spinning, it’s related to a bad capacitor. Could there be another board between the trigger and the motor that contains the capacitors for the motor? Again, not offered as a solution, but as something to think about as you consider the next steps.

 

[waho6o9]

Kapex Armature Instructions.pdf

I'm not sure if this helps but there's a pdf from another Fogger about changing the armature etc....

Best of luck

View attachment 1

 

[Amon Amarth]

Thanks for all the replies guys, I appreciate it. I have triple-checked the cable connections and everything looks good. It looks like all the circuits are integrated on that main board and while it is connected to the start switch and supplies the lasers with power there seems to be nothing between the power cord and the motor except that one board. I did some reading up on the Kapex's brake function which works by means of magnets, hence the clicking feeling when you turn the blade by hand when powered off. As I try to run it it does not simply hum like a completely messed up motor but seems like it tries to move and instantly runs into resistance. My gut tells me the motor tries to move and is able to produce power but the brakes are simply on and won't disengage.

Threads likehttp://festoolownersgroup.com/ask-festool/kapex-blade-brake/msg195262/#msg195262 makes me think the motor unit has taken a beating from the overvoltage and that the magnet brake function is now toast. My initial hopes that the damage is isolated to the circuit board comes from my previous experience with electronics repair, when too much power is blasted onto a circuit it often results in something failing like a resistor for example and once that fails it becomes pretty much like a blown fuse and the damage does not move past that point. But I may not have been that lucky this time around.

I will do some reading up on the motor parts/armature and figure out what may need replacing, I haven't gone into that yet so I don't know if separate parts make up the unit or if you simply buy the whole thing.  Good thing Festool parts are dirt cheap, haha....  [unsure]