Konica minolta bizhub 284e keeps jamming in the third tray (Error 20-21)

[Proffice]

Hello guys
I have a bizhub 284e that keeps jamming in the third tray (error 20-21).
It prints fine by trays 1,2 and 4. I have checked the rollers, the sensors but no help.
Any suggestions?

[patrickjlc]

Swap all pick and feed rollers from tray 4 to tray 3, including the white and the black clutch bearing that are with the rollers and see if it works

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[blackcat4866]

Check to see if the tray #3 exit mylar is deformed.

If you've been already working in the back of the machine, check to see if CN3 is fully plugged in at the EXCB. During replacement of clutch CL8 it's easy to pull on the harnesses and partly unplug connector CN3.

On the C360 I've seen a couple other things:
The customer got a batch of paper that was 0.6mm oversized. Since tray #3 is not size adjustable the paper fit too snugly.

Also if the inner vertical paper guide comes off it's pins you can get 20-21 jams ... but that's pretty obvious to somebody who's investigating.

On the bizhub 423:
I've seen slipping one-way bearings at the feed section.

Or I've seen endusers load ledger sized paper to the tandem tray, then expect it to feed.
=^..^=

[allan]

Does it work if you put pressure on the side door while testing?

[tsbservice]

Swap all pick and feed rollers from tray 4 to tray 3, including the white and the black clutch bearing that are with the rollers and see if it works

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This is really simple and fast test that I like to use in such situations, works almost everytime. 99% of time it's either rollers or oneways/torque limiter.

[EarthKmTech]

in sensor check see if the vertical transport sensor is actually functional in tray 3.

For some reason its always tray 3 that has the pins of this sensors connector get oxidised in environments that wet mop the floors. If its not responsive usually disconnection and reconnection of this sensor fixes the issue - till next time.

[DelawareJim]

Jamming from tray 3 and/ or tray 4. Pull down the side door, and lightly roll upwards on the black transport roller. It should roll upwards easily. If it is hard to roll, suspect the 1-way clutch assembly located at the rear of that transport roller. To service it, remove the feed unit, remove 1 gear that is in the way, and then a c-clip and pull the assembly off. Squeeze the assembly together in your fingers (you may have to also rotate the outside white parts) and you will feel it seat. Then just reinstall the assembly onto the transport roller, but before you put on the c-clip, install a spacer washer or 2. Konica Minolta part number: A108213800. 9 bucks per at Discount Copy Center. We bought a bag of 100 from Aliexpress for 9 dollars and that included shipping. The OEM washer is between .1 and .2 mm, so we bought a bag of .1mm, .2mm, .3mm, and .5mm. This allows us to create the perfect spacer size...not too tight and at the same time no play. Store name on Aliexpres is Jason Hardware World, and the exact washers we ordered were Thickness 0.1mm Stainless steel Flat Washer Ultra thin gasket High precision Adjusting gasket M3-M40 Thin shim SUS304
(https://www.aliexpress.com/snapshot/0.html?spm=a2g0s.9042647.6.14.7b704c4dsICb1y&orderId=8125258003599953&productId=32817597278)Inner Diameter: 6x12x0.1 (100pcs) The 6x12x0.1 is the important part of that. Also 6x12x0.2, 6x12x0.3, and 6x12x0.5 The entire order was 32 bucks and shipping only took about 3 weeks.