Init Paper Shredder sensor circuit

[999999999]

Re: Init Paper Shredder sensor circuit

lol, I am reminded how much of a headache I get trying to trace circuits from random pics. Can you trace the circuit back a bit and with power off, measure resistance with the slide switch flipped one way, then the other? Looking at the switch contacts as two columns in the picture of the back of the PCB, the first two rows of contacts in each column should read very near zero resistance between each other when the switch is flipped that direction, and vice versa for when the switch is flipped the other direction.

[davg]

Re: Init Paper Shredder sensor circuit

That cap is for the DC power supply for running the electronics on the board.
So from the picture: This must be reverse-able motor.
The Yellow and the Green wires are for the motor's brushes?
The Blue and White wires are for the Stator motor winding?
The slide switch on the board, is that for forward/reverse motor function if you have paper jammed?

That is correct it is reversible? The slide switch is Auto - off - reverse. When set to auto the sensor starts the unit

[budm]

Re: Init Paper Shredder sensor circuit

That cap is for the DC power supply for running the electronics on the board.
So from the picture: This must be reverse-able motor.
The Yellow and the Green wires are for the motor's brushes?
The Blue and White wires are for the Stator motor winding?
The slide switch on the board, is that for forward/reverse motor function if you have paper jammed?

[davg]

Re: Init Paper Shredder sensor circuit

"105k 250 volt" is 1uF 10% 250V rating capacitor.
Can we see the pictures of the motor? one lead of the motor should go to the relay contact on the board. There may be motor start-up cap also.
You can bypass the relay contacts once we verify how the whole thing is wired.

Difficult to get a good picture but try this one. I was wondering where that large orange cap was loose on the board if it may have blown something else?

[budm]

Re: Init Paper Shredder sensor circuit

"I checked the voltage across the brushes and I am reading about 57volts?"
This does not make sense, unless the relay has really bad contact or something else is in series with the motor.
I am still waiting for the pictures of the motor and how they are wired up together.

[999999999]

Re: Init Paper Shredder sensor circuit

^ but my point was, it getting hot in a test isn't necessarily a sign of anything, they cut costs by using a motor that can't run continuously because it's expected to get hot.

[budm]

Re: Init Paper Shredder sensor circuit

Most shredder will have thermal switch that shut down the motor when it gets too hot.

[999999999]

Re: Init Paper Shredder sensor circuit

You already know the motor works, just measure whether it's getting 120VAC when in the circuit and running. Carefully.

The motor may easily get hot without it being a sign of anything wrong. They generally use small/cheap intermittent duty motors for little shredders like this and then instruct that you're only supposed to run them for a short time before a cool down period is needed.

The other possibility is that the cutters are dull. If they do not cut through the paper cleanly and quickly but rather mash it apart it will slow the shredder down.

Do a test. Put in a narrow strip of paper and see how long it takes. Next put in a full width strip of paper and see if it takes longer. If it takes more than a fraction of a second longer, the cutters are probably dull.

[budm]

Re: Init Paper Shredder sensor circuit

"105k 250 volt" is 1uF 10% 250V rating capacitor.
Can we see the pictures of the motor? one lead of the motor should go to the relay contact on the board. There may be motor start-up cap also.
You can bypass the relay contacts once we verify how the whole thing is wired.

[davg]

Re: Init Paper Shredder sensor circuit

Please try and check first that it is a 120vac motor -it should have some sort of plate/label on it

Yes it is stamped right on the motor 120 volts 60hz

[selldoor]

Re: Init Paper Shredder sensor circuit

Please try and check first that it is a 120vac motor -it should have some sort of plate/label on it

[davg]

Re: Init Paper Shredder sensor circuit

Can you clean /lubricate the motor bearings?
Can you clean the slots where the brushes contact the armature.
It could of course just be the motor is worn out - does it seem to get hot quickly?

The bearings seem ok I did clean the armature and the motor turns freely by hand while disconnected, and can turn the cutters ok by hand with the gears removed. The motor is not getting hot but then I am not leaving it running for along time. It is a 120 volt motor so if I were to by-pass the board and but 120 volts to the motor that should narrow things down?

[selldoor]

Re: Init Paper Shredder sensor circuit

Can you clean /lubricate the motor bearings?
Can you clean the slots where the brushes contact the armature.
It could of course just be the motor is worn out - does it seem to get hot quickly?

[davg]

Re: Init Paper Shredder sensor circuit

That orange cap and the 100 Ohms resistor are part of the current source power supply circuits feeding the bridge rectifier Diodes so it does not need power transformer for the electronics. The relay is for the AC motor that drives the shredder, yes try cleaning and lubrication, probably the paper dust particles clog up the bearing, just like it clogged up the sensor.

I think what I called a cap is actually a 105k 250 volt resistor? (The big orange one) I checked the voltage across the brushes and I am reading about 57volts? I removed the gears running the shredded to eliminate a possible clog, and the motor is still running slow almost like bad brushes, but checking the brushes they seem OK. Since I don't have a drawing I do not know what the voltages should be.

[budm]

Re: Init Paper Shredder sensor circuit

That orange cap and the 100 Ohms resistor are part of the current source power supply circuits feeding the bridge rectifier Diodes so it does not need power transformer for the electronics. The relay is for the AC motor that drives the shredder, yes try cleaning and lubrication, probably the paper dust particles clog up the bearing, just like it clogged up the sensor.

[999999999]

Re: Init Paper Shredder sensor circuit

^ agreed, it probably needs cleaned out and lubed... or you could just try lubing it first.

A quick way to lube the blades that's not much different than buying the real retail lube sheets is to just wet a regular piece of paper with mineral oil and run that through, but you may also have paper dust clogging the gears or even getting into the motor bearings.

[selldoor]

Re: Init Paper Shredder sensor circuit

I know nothing about shredders electronics but my guess would be the cap is ok. It looks melted in one pic but thats just the pic - right?
Other members may have more knowledge. If it were mine I would
turn my attention to the gears, the motor and the cutters - they do tend to get clogged up with paper and paper dust. Cutters I think it recommends cleaning and spraying on a very regular basis even daily depending on usage.
The gear cogs are often greased and that with the paper dust makes a very effective brake.

[davg]

Re: Init Paper Shredder sensor circuit

Here are the pictures I promised hope they are ok. I know that the sensor is not gone and the unit do not run continually any more. I cleaned the sensor and that took care of that problem, however it is still not working properly. It seems to be running very slow? I checked the main board and found that the 105k 250volt capacitor was loose on the board,I re-soldered it hoping that was the problem but not to be. Is it possible that this capacitor could be the problem? Can it be tested on the board?

[davg]

Re: Init Paper Shredder sensor circuit

I should have thought these were the type of thing you need
though what value ??
First try cleaning up the old ones with some isopropyl alcohol

http://www.digikey.co.uk/product-sea...mitters/524328
http://www.digikey.co.uk/product-sea...ed%20collector


Here is a link to a schematic for "a" shredder might help
perhaps you can find one for yours?

We may be able help more if you please post good clear pictures of each board, front and back and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

Please do not post inline and offsite as they slow down the loading of pages.

Examples of what is needed
https://www.badcaps.net/forum/attach...1&d=1290283049

https://www.badcaps.net/forum/attach...7&d=1280167246

Thanks I will post pictures tomorrow after I take it down again. Because one of the led is black in color I assumed it to be blown?? I will have a closer look tomorrow. Thanks again for the reply

[budm]

Re: Init Paper Shredder sensor circuit

The two looking LED's, one is the LED (light emitter source), one is a receiver (Photo sensor Diode, it can have dark looking body since it is Infrared).
You should be able to shine bright flashlight into the slot and see if it will stop the motor.
You can also have shorted TRIAC for driving the motor that is controlled by the sensing circuits.