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[N2NJO]

This is a good one, especially since it involves the drill changing directions from one day to the next. (The motor assembly was changed out previously)

Long story short:
Bosch hand held drill chuck rotation was reverse what it should be. I opened the enclosure and reversed the motor leads and all was fine. I used it a number of times that same day. The very next day when I checked to confirm all was ok, it reverted back to opposite rotation by itself. Forward was reverse, etc.

There are two transistors (3 leg) attached to the heat sink in the base of the handle and one other component (2 pin), rectangular in shape. My guess is it's a capacitor, but I never saw one like that before, the corners were not rounded. If there are any other components, they would be in the trigger switch itself.

Ok, would someone like to explain WTF is going on? I haven't tried to re-reverse the motor leads again yet. Getting the motor leads reversed is one thing, but how can the direction just change from one day to the next, there is no microprocessor circuit here?

[AF6LJ]

Sounds like your drill has a defective microcontroller.
With that said here is a stop gap measure.
https://www.mcmaster.com/#left-hand-drill-bit-sets/=19kx8yn

[KC4ZGP]

Bosch is German. They use 220 volts 50 Hz in Europe.

We use 120 volts 60 Hz.

Anything else?

Kraus

[N2NJO]

And the microcomputer is exactly located where?? Changing drill bits?? Why, The reverse switch works, just opposite of what it should.

Europe vs US electrical is of NO issue. Just because they are a German company, models sold here are for the US like any other product that is foreign based. I don't know why you even brought that up. 

[AA4PB]

Is this a battery operated drill? Most of them have a reverse switch to permit changing rotation direction. Is it possible that you bumped the switch causing it to reverse?

[K0UA]

And the microcomputer is exactly located where?? Changing drill bits?? Why, The reverse switch works, just opposite of what it should.

Europe vs US electrical is of NO issue. Just because they are a German company, models sold here are for the US like any other product that is foreign based. I don't know why you even brought that up. 

Because Kraus fully intends to be a stand up comic some day, and he is practicing his material here on a captive audience. I am not sure he is going to make it in his new endeavor, and perhaps he should keep his old job he has in the daytime in good stead. Or to put it another way, Kraus craves attention, and will get it any way he can.  He loves to say stupid things because it gets peoples attention.  It worked in this case. Heck he got me to waste a few hundred keystrokes just explaining it...

[N2NJO]

Yes it is battery operated, I thought that was in the OP, but it was not. My bad there, I'm usually more thorough.

The reverse switch is fine, no issues, no dead spots or intermittent operation and it's not a "bumped' issue. It's a real pain to open it back up due to the tightness of the screws (worst I ever encountered) and the possible proprietary head slot.

[AA4PB]

So with the reverse switch in the forward direction, sometimes it runs CW and sometimes it runs CCW but you can always change direction by changing the switch position?

[N3QE]

Some high-end battery powered tools now use brushless motors with motor controllers. The motor controller is a multi-legged power IC, usually on a PCB that also contains the motor frame windings, and this sets the direction based on external input.

Usually the motor controller will be a PCB on the motor, not on the direction switch, but I don't know the details of this Bosch.

Tim.

[AF6LJ]

And the microcomputer is exactly located where?? Changing drill bits?? Why, The reverse switch works, just opposite of what it should.

Europe vs US electrical is of NO issue. Just because they are a German company, models sold here are for the US like any other product that is foreign based. I don't know why you even brought that up. 

If it is variable speed and reversible there is a microcontroller running the show.
If it uses LI-ON batteries you can bet your life there is a microcontroller to manage current draw and battery temp...


The left hand drill bits were intended to be sort of a joke.

[K8AXW]

I second 4PBs answer..... you do indeed have a mysterious problem but as in some cases, the cure is worse than the problem.

I'd just check the direction prior to use and if necessary flip the switch.

In the meantime, I'd contact the maker and ask them what is going on with their tool!  This should be interesting because Germans can't tolerate imperfection.  It drives them nuts.

As for Kraus's pointless answers; everyone stop clapping and get back to your beer.

[KD0REQ]

heck, every box of nails I buy has heads on the wrong end about half the time.

compensate.

hold the hammer head and whack 'em with the handle.

[K4JJL]

Because Kraus fully intends to be a stand up comic some day, and he is practicing his material here on a captive audience. I am not sure he is going to make it in his new endeavor, and perhaps he should keep his old job he has in the daytime in good stead. Or to put it another way, Kraus craves attention, and will get it any way he can.  He loves to say stupid things because it gets peoples attention.  It worked in this case. Heck he got me to waste a few hundred keystrokes just explaining it...

[KC4ZGP]

You guys are funny. We're all funny and all incredibly bored or none of us would be here.
I'm at work right now.

I do check in here in the evening at home just to see if someone has money for me.

My point being, I lived in Europe for five years. Everything seemed backwards. Or I
was just going the other way.

1.815MHz, Morse, 2200UTC anyone brave enough to outdo The Kraus.

Kraus

[N2NJO]

Some high-end battery powered tools now use brushless motors with motor controllers. The motor controller is a multi-legged power IC, usually on a PCB that also contains the motor frame windings, and this sets the direction based on external input.
Usually the motor controller will be a PCB on the motor, not on the direction switch, but I don't know the details of this Bosch.
Tim.

Not a brushless motor.

Ok, answer this; the issue isn't that the direction is reverse of what it should be, but why did operation change (reverse) by itself the next day after it ran correctly? Can there be some correlation between the specific motor and the external electronics that it did some 'correction' on it's own (for lack of a better description)?
This motor assembly (includes the clutch & chuck) was swapped with another identical drill to troubleshoot a different possible problem not related to this.