This crappy paper shredder uses a mechanical sensor to detect paper
inserted, I think how it "works" is the lever arm rotates forward (to
the left in the photo) hitting the momentary switch, the motor comes on
and the worm gear attached to the driveshaft raises the smooth plate
pulling the arm forward again until it hits the switch again, turning
the motor off...I'm not sure that's quite right maybe someone could
clarify the sequence.

Kinda ingenious design when it works right, except in this model it
never really did, the motor always spun too long and now it won't
auto-detect entirely. The smooth plate likes to slip out of its
position, but I'm unsure of its resting position or how tight the set
screw above the spring needs to be to fix it (not sure what else could
go wrong...) At least until I finish this shredding job and take it to
the Goodwill, that is.

Pics of the arrangement:

<https://imgur.com/a/kuKct9f>

On Friday, April 7, 2023 at 4:29:07 PM UTC-5, bitrex wrote:
> This crappy paper shredder uses a mechanical sensor to detect paper
> inserted, I think how it "works" is the lever arm rotates forward (to
> the left in the photo) hitting the momentary switch, the motor comes on
> and the worm gear attached to the driveshaft raises the smooth plate
> pulling the arm forward again until it hits the switch again, turning
> the motor off...I'm not sure that's quite right maybe someone could
> clarify the sequence.
>
> Kinda ingenious design when it works right, except in this model it
> never really did, the motor always spun too long and now it won't
> auto-detect entirely. The smooth plate likes to slip out of its
> position, but I'm unsure of its resting position or how tight the set
> screw above the spring needs to be to fix it (not sure what else could
> go wrong...) At least until I finish this shredding job and take it to
> the Goodwill, that is.
>
> Pics of the arrangement:
>
> <https://imgur.com/a/kuKct9f>

Try a good cleaning before you toss it. Maybe the switch is full of paper dust.

On 4/7/2023 10:20 PM, tschw...@aol.com wrote:
> On Friday, April 7, 2023 at 4:29:07 PM UTC-5, bitrex wrote:
>> This crappy paper shredder uses a mechanical sensor to detect paper
>> inserted, I think how it "works" is the lever arm rotates forward (to
>> the left in the photo) hitting the momentary switch, the motor comes on
>> and the worm gear attached to the driveshaft raises the smooth plate
>> pulling the arm forward again until it hits the switch again, turning
>> the motor off...I'm not sure that's quite right maybe someone could
>> clarify the sequence.
>>
>> Kinda ingenious design when it works right, except in this model it
>> never really did, the motor always spun too long and now it won't
>> auto-detect entirely. The smooth plate likes to slip out of its
>> position, but I'm unsure of its resting position or how tight the set
>> screw above the spring needs to be to fix it (not sure what else could
>> go wrong...) At least until I finish this shredding job and take it to
>> the Goodwill, that is.
>>
>> Pics of the arrangement:
>>
>> <https://imgur.com/a/kuKct9f>
>
> Try a good cleaning before you toss it. Maybe the switch is full of paper dust.

I'll try that as well but I forgot to mention that the first
fail-symptom was the plastic trigger was stuck in the forward position
blocking the paper slot, sorry about that!

So I think maybe there's something mechanical going on with the
arm/gear, also. The lil metallic switch trigger seems to move freely
otherwise.