Paper Shredder Fault

[73's de Edd]

Just a note I may have the A44 transistor the wrong way round on the drawing, it is difficult to see which way , has I am looking at it on the underside of the board and the transistor front ( flat part) is facing away from the contacts looking at it from the top .
As is being viewed from the top, the unit is being correctly installed, if the curved side of the plastic is on the side of the two black E-caps. And the flat side being FAR away from them.

Physically OPAQUE, intermittent blocking of the path of IR emitter to photocell should cause the voltage at the photocell to ground, to bobble up and down acccordingly.
UNLESS . . .considering . . that the present high ambient level of CONVENTIONAL room lighting, falling onto the photocell, with it not being being hidden down in its otherwise encased and darkened cavity . . . . would also have the potential A44 base drive voltage being grounded out by the phototransistor.
And if I remember correctly, even BLACK plastic electrical tape shielding of the phototransistor is not being an effective blocker of IR passage.

Also the ir emitter that feeds the photoelectric sensor is not lit , checked with a ir detector ! .
Sub in a properly polarity, installed conventional RED LED to observe, as it should always be lit.

Different topic . . . where was the units MICRO switch installed ?

 

[spike1947]

Just a note I may have the A44 transistor the wrong way round on the drawing, it is difficult to see which way , has I am looking at it on the underside of the board and the transistor front ( flat part) is facing away from the contacts looking at it from the top .
As is being viewed from the top, the unit is being correctly installed, if the curved side of the plastic is on the side of the two black E-caps. And the flat side being FAR away from them.

Physically OPAQUE, intermittent blocking of the path of IR emitter to photocell should cause the voltage at the photocell to ground, to bobble up and down acccordingly.
UNLESS . . .considering . . that the present high ambient level of CONVENTIONAL room lighting, falling onto the photocell, with it not being being hidden down in its otherwise encased and darkened cavity . . . . would also have the potential A44 base drive voltage being grounded out by the phototransistor.
And if I remember correctly, even BLACK plastic electrical tape shielding of the phototransistor is not being an effective blocker of IR passage.

Also the ir emitter that feeds the photoelectric sensor is not lit , checked with a ir detector ! .
Sub in a properly polarity, installed conventional RED LED to observe, as it should always be lit.

Different topic . . . where was the units MICRO switch installed ?

Micro switch is taped close, while testing ! .
cheers
Spike

 

[spike1947]

Just a note I may have the A44 transistor the wrong way round on the drawing, it is difficult to see which way , has I am looking at it on the underside of the board and the transistor front ( flat part) is facing away from the contacts looking at it from the top .
As is being viewed from the top, the unit is being correctly installed, if the curved side of the plastic is on the side of the two black E-caps. And the flat side being FAR away from them.

Physically OPAQUE, intermittent blocking of the path of IR emitter to photocell should cause the voltage at the photocell to ground, to bobble up and down acccordingly.
UNLESS . . .considering . . that the present high ambient level of CONVENTIONAL room lighting, falling onto the photocell, with it not being being hidden down in its otherwise encased and darkened cavity . . . . would also have the potential A44 base drive voltage being grounded out by the phototransistor.
And if I remember correctly, even BLACK plastic electrical tape shielding of the phototransistor is not being an effective blocker of IR passage.

Also the ir emitter that feeds the photoelectric sensor is not lit , checked with a ir detector ! .
Sub in a properly polarity, installed conventional RED LED to observe, as it should always be lit.

Different topic . . . where was the units MICRO switch installed ?

Tried a ordinary RED led, not lighting , measured voltage across points, 5v ! .

 

[Bluejets]

RED LED backwards..??

 

[spike1947]

RED LED backwards..??

Tried both ways,
Am wasting too much time for you guys, I need to get something sorted quick, so I am going to try and make a ir break circuit relay board, to work along side with the old board ! .
Spike

 

[Bluejets]

Time spent so far is in determining what you have in front of you from your replies.
So if it is taking too much time for your liking, there is only one source of the problem.
If you have 5v available across the existing IR LED, then a red led should work......so what have you done there.....??

 

[spike1947]

Time spent so far is in determining what you have in front of you from your replies.
So if it is taking too much time for your liking, there is only one source of the problem.
If you have 5v available across the existing IR LED, then a red led should work......so what have you done there.....??

Hi
Thanks for your reply , I made a mistake in the reply to you, it should of read " 0.5vcc" not 5vcc, I thought that I had put .5v .
ps: It is not my time I am wasting it is all the people that are answering my query, I have tried everything that has been suggested up to now, there has to be a cut off point ! .
Am not abandoning it , just going a different route to try to get to the same result !
Cheers
Spike

 

[spike1947]

This is what I am thinking of doing , to join up to the other board which has the forward and reverse switch on it .

cheers
Spike

 

[73's de Edd]

Sir spike1947 . . . . . . aka the "spikester"

Is that some old schematic derivation from off the internet. as those JAMECO parts numbers are from the 80's.
Also don't you think that I was worthy enough to know that this is dads unit ?
NOW . . .the first thing that I will be needing is for you to do is to take the UNPOWERED unit and measure across its relay contacts to see if its contacts are normally open or closed if being in a NON energizedcoil condition.
If you traced my BLUE arrow power flow route before, it would be needing a closed relay contact, then as a paper fill FULL condition would turn on the A44 and it would activate the relay which would disrupt power to the motor until the bin was emptied.
I can't know your answer yet but I will step ahead and give you the next test which would be to power up the system and take a short length of insulated hook up wire to then plac its bared ends from one end of theA44 transistor to the other end. That should cause the relay to click to its other state. Then remove the jumper and do a DC low voltage test with probes from A44 center pin base to A44 far pin emitter that connects thru the D5 diode to ground.
We need upwards of ~ + 7 tenths of DC voltage at that base for the transistor to be able to conduct to activate the relay.
If that is not the case, then leave the ground probe in place and back track with the + probe to D6 and then R5 and then the other side of R5 at the D4 and D1 junction source, which I believe that you measured as being 3 voltish last time.
This SHOULD now let us figure out the relay, its A44 driver and the questionable relay contacts . . N.O. or N.C. situation.
No way would I go with that auxililiary board build.
A forthcoming query will be directed to that somewhat wierd duck exposed RED LED on a step up pedestal and its abnormal R1 and R4 resistors and conjunct unidirctional D1 diode. Thus, suggesting that it is working off raw 220VAC.
Any chance that its BROWN wire from R1 goes to a round KLIXON type of snap action disc thermostatic disc that is thermally bolted to the shredder motor ??





ZUJ'ing . . . . . . .

73's de Edd . . . . . .

 

[spike1947]

Sir spike1947 . . . . . . aka the "spikester"

Is that some old schematic derivation from off the internet. as those JAMECO parts numbers are from the 80's.
Also don't you think that I was worthy enough to know that this is dads unit ?
NOW . . .the first thing that I will be needing is for you to do is to take the UNPOWERED unit and measure across its relay contacts to see if its contacts are normally open or closed if being in a NON energizedcoil condition.
If you traced my BLUE arrow power flow route before, it would be needing a closed relay contact, then as a paper fill FULL condition would turn on the A44 and it would activate the relay which would disrupt power to the motor until the bin was emptied.
I can't know your answer yet but I will step ahead and give you the next test which would be to power up the system and take a short length of insulated hook up wire to then plac its bared ends from one end of theA44 transistor to the other end. That should cause the relay to click to its other state. Then remove the jumper and do a DC low voltage test with probes from A44 center pin base to A44 far pin emitter that connects thru the D5 diode to ground.
We need upwards of ~ + 7 tenths of DC voltage at that base for the transistor to be able to conduct to activate the relay.
If that is not the case, then leave the ground probe in place and back track with the + probe to D6 and then R5 and then the other side of R5 at the D4 and D1 junction source, which I believe that you measured as being 3 voltish last time.
This SHOULD now let us figure out the relay, its A44 driver and the questionable relay contacts . . N.O. or N.C. situation.
No way would I go with that auxililiary board build.
A forthcoming query will be directed to that somewhat wierd duck exposed RED LED on a step up pedestal and its abnormal R1 and R4 resistors and conjunct unidirctional D1 diode. Thus, suggesting that it is working off raw 220VAC.
Any chance that its BROWN wire from R1 goes to a round KLIXON type of snap action disc thermostatic disc that is thermally bolted to the shredder motor ??

View attachment 50091



ZUJ'ing . . . . . . .

73's de Edd . . . . . .

Hi
Thanks for your reply, am not going with that old schematic, was going to try a auxiliary board as you put it as per attached schematic ! .
given by " dodgydave" on this forum !, but will do the checks you have mentioned first .

Cheers
Spike

 

[spike1947]

Relay is normally open !

 

[spike1947]

Hi
I The paper feed sensor output keeps the relay on for a few seconds, through a peak detector type circuit ! , it has to do this to give time for the paper to go through the shredder after passing through the sensor at the top of the Shredder ! .

Spike

 

[bezspamu]

Hi,
Have you figured out what's the problem? I have exactly the same shredder and the same problem - works only in reverse mode. Cleaned out IR but no effect. Thanks

 

[spike1947]

Hi there
No I didn't, it was a problem with the sensors circuitry on the PCB Board, I had to solder a bypass wire on the board ( easy to do ) , to be able to use it manually forward and reverse, which is fine by me .
Cheers
Spike

 

[bezspamu]

Hi,
The sensors were my first suspicion so tested with a multimeter and seem to be working fine - LED has a constant voltage of 1V and the IR has continuity when not paper present and around 2.2V when a paper is present in the sensor.
Also tested the two yellow capacitors (104k X2) and at least one of them is faulty (multimeter shows 18nF). Ordered both for replacement and will let you know if it helps in my case

 

[bezspamu]

Hi there,
In my case changing the two big capacitors that I mentioned above fixed the issue. Works flawlessly now!

 

[gbsimpsa]

Hello all, Tony here, I Just found this forum.

Yesterday, I was given one of these shredders with the same symptoms. Reverse OK, Auto doesn't work.
A bit of Googling and I'm amazed how many people seem to have reported the same fault with this Amazon Basics shredder.

So here's what I've found out:
First thing I did was bypass the Relay, I carefully shorted the N/O Contact (AC Mains!!) and it sprang into life, Checking the IR sensing circuit with paper I confirm that all works ok.
The relay is a 24V type (JQC-3FF) , but as someone else similarly found, the Voltage drop across it is insufficient to engage the contacts.
Working back, I can see the base drive on Q1 is a little low at about 1V (bearing in mind there is a diode on it's emitter), and is effectively high impedance/Off,.
So I bypassed C-E of Q1 and yet again the shredder sprang into life. I have a SCR in mine but that is not in conduction so moving on....
So working back from there I see the Voltage on ZD1 (Taiwan Semi 1SMA4742) is meant to be 12V however I measured around 3V.
So to give it a little helping hand I put 10V across ZD1 and again it springs into life.
D3, D4, R2, the IR diode and C1 all measure out ok.

I haven't dug a soldering iron out yet, or disconnected anything, to prove this theory, and I might yet be wrong, but I suspect my fault (and probably many others) is ZD1 going leaky.

I'll do my best to prove it in the next few days and report back.

Could it be down to a 30pence Zener and (what I think is) a rather crude and crusty design (Well it is a Basics I guess"!)
I wonder how many have just ended up in Landfill.

 

[gbsimpsa]

And Finally, Solved....
Turns out it was the yellow Poly Cap C5 after all (Sorry I doubted you ZD1).
I took them both off to measure and they've both started to degrade. C5 worse than the main line filter.
So as a quick (and temporary fix) I swapped them around and it works again.