Problems with a Sharp AR-286

[Guest]

I have a old AR-286 that has recently developed a jamming problem. It'll feed paper until it hits the end of the drum where it becomes hooked and folds over itself three times before the remove paper jam error comes up. I pulled the whole drum unit out and then the drum itself and found some torn up paper wedged between the drum and its holder, after removing the paper and reinstalling it I still have near the same problem. The paper will roll up around the drum and get stuck folding over on itself. Anybody have any suggestions or ideas before I call in the experts?

Thanks

[JustManuals]

Re: Problems with a Sharp AR-286

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[Nachoman4life]

Re: Problems with a Sharp AR-286

I'd test the drum separation solenoid in sim 6, if it checks ok, check the transfer/separation unit for grounding out. (usually a line of toner will be visible where the path to ground is going.

[blackcat4866]

Re: Problems with a Sharp AR-286

IMHO, if the drum separation solenoid is necessary, there is a separation charge loss. It could be a broken charge wire (any of them, shorting out the HVT), or a shorted separation corona unit.

The paper should never get anywhere near the drum separation claws if the separation charge is working properly. =^..^=

[amertrash]

Re: Problems with a Sharp AR-286

Thanks for the help guys, had a long weekend off in between. Looks like my problem is one of the two plastic claws that push against the drum when a solenoid fires to pull the paper down is broken off. I forgot to bring my meter so I can't test the separation unit for grounding out today. I'm no copier tech(more of a network IT guy) so excuse the lack of proper terms/dumb questions. I'm assuming that having that one broken claw is enough for the machine to jam, or would that still be unlikely if the transfer/separation unit was working correctly?

[johnbla]

Re: Problems with a Sharp AR-286

The chances are that the Drum Sep Finger broke during the initial paper removal from around the Drum... and was the effect and not the cause...

Remove the Sep Corona unit... the Yellow Unit in the lift-up frame below the Drum and check that there are not obvious Black powder marks or Scorch marks, which would indicate a Earth short or Arc and that there is a fine Corona wire running between the two spring holders in each channel.

If there is a problem.. with Arc/Scorch replace the whole Unit, if only Corona wire failure.... re-string the Bow...have fun.

Hope this helps

[ZOOTECH]

Re: Problems with a Sharp AR-286

The chances are that the Drum Sep Finger broke during the initial paper removal from around the Drum... and was the effect and not the cause...

Remove the Sep Corona unit... the Yellow Unit in the lift-up frame below the Drum and check that there are not obvious Black powder marks or Scorch marks, which would indicate a Earth short or Arc and that there is a fine Corona wire running between the two spring holders in each channel.

If there is a problem.. with Arc/Scorch replace the whole Unit, if only Corona wire failure.... re-string the Bow...have fun.

Hope this helps

johnbla is correct; there is also a ground wire at the rear of the lift-up frame that can be broken when customer rotates the handle 360 degrees.

[chubblies]

Re: Problems with a Sharp AR-286

As Zootech says, it was a very common problem on these machines whereby the bed lever would be turned the wrong way, causing the white nylon lift cams that raise it to snap, and therefore the bed section not lifting up to the drum unit correctly.
When you look into the machine and turn the bed lever 90 degrees, does the section lift up? If you push the bed section up towards the drum unit by hand as far as it will go for reference, the bed lever should move it to the same position when in the up position.
Another common fault was the reg and pre reg clutches overfeeding and creating too much of a paper buckle, this very often jammed under the drum, the clutches are a right pain to change too.
Run it with the front door open and tell us what you can see when it jams if possible...

[blackcat4866]

Re: Problems with a Sharp AR-286

Like everybody has already said, the drum claw needs fixing, but is more likely a consequence, not a cause. The transfer/separation high voltage unit, like the name indicates, uses high voltage, 1000's of volts, but only mA. You won't be able to measure a short. You will be able to identify a missing corona wire. More likely, the endblocks (gray plastic insulator ends) will start to leak current. In the beginning it will look like a little white ash on the inside of the block. As it gets worse, the inside of the block will turn a mustard yellow color with an ashy coating. When it's completely failed you can frequently see black trails across the surface of the block, and often hear snapping sounds as the high voltage arcs to ground.

Chubblies describes the bed lift mechanism quite nicely. There's no improving on that.

If you do have a broken corona wire you may find it easier to just replace the assembly. Or find a local tech willing to string a few wires for you. This is one of the few things we do that requires some dexterity. Hopefully your tech will have a few gray hairs. Otherwise he may have to ask you what a corona wire is. =^..^=

[argos]

Re: Problems with a Sharp AR-286

in the surface of the drum has 2 paper guides - like fingers.
These should be placed on the surface of the drum
One of them is gone from the spring and prevents the passage of the paper
Take out the drum unit and looked carefully under the drum and you will understand what to do
good luck

[amertrash]

Re: Problems with a Sharp AR-286

Thanks guys, you all rule. Free beer for anyone who is in South Dakota in the future

Remove the Sep Corona unit... the Yellow Unit in the lift-up frame below the Drum and check that there are not obvious Black powder marks or Scorch marks, which would indicate a Earth short or Arc and that there is a fine Corona wire running between the two spring holders in each channel.

The corona wires look fine - I pulled the clear little plastic caps off the ends of the separation unit and I can see a fine black line between the end block and the outer metal frame which I'm guessing is my short. I didn't say this before as I'm an idiot but before a couple times a month you'd here a popping sound and the machine would throw its breaker and restart, I assume that was the corona shorting to ground.

johnbla is correct; there is also a ground wire at the rear of the lift-up frame that can be broken when customer rotates the handle 360 degrees.

Looking again I see the ground wire at the top rear left of the frame, it looks fine and checked resistance between the lift-up frame and the chassis ground and it was fine.

As Zootech says, it was a very common problem on these machines whereby the bed lever would be turned the wrong way, causing the white nylon lift cams that raise it to snap, and therefore the bed section not lifting up to the drum unit correctly.
When you look into the machine and turn the bed lever 90 degrees, does the section lift up? If you push the bed section up towards the drum unit by hand as far as it will go for reference, the bed lever should move it to the same position when in the up position.

Pushing the bed up manually leaves about 1/16" - 1/8" of play versus using the cam lever, and the round nylon ends on both front and back look good yet.

Finding a service manual/parts list online was a big help, I take it I should replace the whole TC unit along with the broken pawl now?

[chubblies]

Re: Problems with a Sharp AR-286

Finding a service manual/parts list online was a big help, I take it I should replace the whole TC unit along with the broken pawl now?

You can just replace the end blocks and covers, and re-string it, as parts for them are getting few and far between these days, and you may be more likely to get a seperate end block than a complete assembled unit.
Saying that, I remember how frustrating and fiddly it can be to re-string a wire, so it may be easier to order it complete lol!
Good luck!

[amertrash]

Re: Problems with a Sharp AR-286

Well I've ghetto'ed it up for now, took my pocket knife and simply scrapped away the the burn(along with about 1/32" of plastic on the end block to get it all the way out) and she is up and working again. I found the pawl for $20, still looking for a complete TC unit. If I don't find one I'll be back to ask how to re-string the wire which I bet is loads of "fun".

Thanks again guys.

[blackcat4866]

Re: Problems with a Sharp AR-286

Congratulations. =^..^=