I have one of the first production models of the 1613EVS and have had two problems with it in the last several years of light duty use.

I am a recreational woodworker, not a repair technician. The following experience is being shared in good faith to help others resolve problems with the router. All risk and liability associated with following this advise remains with the reader not the author.

On this early model, the ON/OFF switch in the handle has a two piece case construction. It appears to be glued, with no way to open it to expose the electrical contacts inside. I noticed, however, that tapping the switch and blowing into the microscopic gaps produced a very small stream of super fine dust to exit the interior of the switch. After 15-20 minutes of constant fussing (mostly tapping while simultaneously depressing and releasing the switch) the power came on when the router was plugged back in and the switch was pressed normally. Bosch appears to have redesigned this switch on newer production models. The latest part doesn't appear to have any gaps for dust to enter, so a replacement switch may be in order when you grow weary of cleaning the old one after every few hours of operation.

This is scary and potentially dangerous!

This problem is most pronounced on my unit when the router is close to the maximum plunged position and mounted in a table.  Others have experienced the same problem while using the unit hand held.  In both operations, this is probably the most frequently used depth range because, as most of us know, you can never quite get enough bit sticking out from that base. During hand held operation, others stated that the router continued to plunge down while in use. In my case, the router was tight and did not move after locked when pushed in the direction that exposes more bit (plunged more). But mounted upside down in the table, the weight of the unit would occasionally pull the bit continuously down through the base during use, shrinking the amount of bit protruding onto the tabletop. About the only time that this MAY not be a problem is when a straight bit is being used for trimming. For all operations, especially when using a profile bit, the consequences are ruinous. And if you are foolish enough to have inserted a bit from the outside of the base that has a diameter LARGER than will fit through the hole in the base, you are asking for a serious injury! When the unit sinks low enough, it will pull the bit into the base and create instant shrapnel. On two occasions, without warning, the unit violently dropped to its maximum extended position, pulling the bit down through the hole in a fraction of a second. All of the blood drained out of my face in the blink of an eye.

Good news! The fix was easy on my unit. The problem was that the skinny top of the locking lever was bumping into the motor housing before the unit was fully locked in place.

• Find the locking lever (it looks like a giant plastic comma).
• Remove the single screw holding it in place.
• Gently remove the lever just a tiny bit to allow you to rotate it on the locking shaft. This will allow you to move the top of the lever away from the motor housing. Note: There is a nut on the end of the locking shaft that fits into a molded hole in the cap. You are trying to remove the locking lever just enough to unseat the nut from lever, but not so much as to allow the spring to become undone. The nut is welded to the shaft, so it won't fall off inside the locking lever.
• Replace the screw and your done.

I must confess that I thought about rotating the locking lever without totally removing it only AFTER I disassembled everything. I don't know if it is actually possible to rotate the lever without tearing everything apart or the spring becoming dislodged from the lever, but it's worth a try. If you can't rotate the locking lever without the spring coming undone, or you just want to see how the thing is put together, then continue reading.

• After gently removing the lever just a tiny bit to allow access to the spring, carefully compress the spring with a screwdriver and release it from the notch on the motor housing (there isn't a great deal of pressure, so don't worry about it flying all around as you release the tension).
• Finish removing the lever

Notice that the locking mechanism is nothing more than a brass (or brass color) tube threaded on the inside with a nut welded onto the end that fits into the plastic locking lever.

• Insert the bent end of the spring back into the lever with the bend sticking into the skinny tip of lever. Notice that the spring partially obstructs the molded hole where the nut rests inside the lever. Just ignore this for now.
• Begin replacing the lever, with spring already inserted, onto the shaft.
• Guide the straight end of the spring back into the notch on the motor housing.  The locking lever will not yet be touching the nut.
• Reposition the lever on the nut to allow tightening without causing the lever to prematurely bump into the motor housing. Note: The process of turning the lever to align the molded hole with the nut will compress the spring far enough to unblock the hole in the lever that was obstructed by the spring.
• Insert the screw back into the locking lever and you're done.

It is possible that the manufacturer located the locking lever close to the body originally to prevent the user from over-tightening the mechanism. Keep this possibility in mind now that you have extra room between the lever and motor body. You may want to use only enough pressure to firmly hold the router in place. I'm guessing that excessive pressure may not be good for the unit over its life.

To quote Norm, "Remember, there is no more important safety rule than to wear these safety glasses"