FS-4020dn Close rear unit message

[Donnie]

This is a machine from another techs area with 25k on it i'm wanting to sell to one of my customers, at a nice discount. I have not worked on it myself so all i know is what i've been told. Initial set up was in an unheated, uncooled environment, when temps were extremely cold printer would show message of close rear unit , message would not clear until temps went up. High temps caused complaint of dark streaks. Machine was brought into shop loaner 4000 was put in its place. Dark streaks could not be duplicated, but we did not blast it with heat. Message was duplicated by putting machine in fridge for a little while and close rear unit appears. Meanwhile 4000 works fine, Cpu,temp pcb, rear unit switch have been replaced, since environment conditions were out of spec. you cant really say printer is at fault. Traded out with 4000 months ago it is working fine. We figured in a better environment printer would be fine. I get 4020 to check out for delivery it jams every print at exit, has message of close top cover (different cover) that will not clear, after clearing several jams, powering on/off printer finally works. I know operating environment was out of spec. but I dont think that was the problem. Any ideas? Thanks.

[DWise]

Re: FS-4020dn Close rear unit message

This is a machine from another techs area with 25k on it i'm wanting to sell to one of my customers, at a nice discount. I have not worked on it myself so all i know is what i've been told. Initial set up was in an unheated, uncooled environment, when temps were extremely cold printer would show message of close rear unit , message would not clear until temps went up. High temps caused complaint of dark streaks. Machine was brought into shop loaner 4000 was put in its place. Dark streaks could not be duplicated, but we did not blast it with heat. Message was duplicated by putting machine in fridge for a little while and close rear unit appears. Meanwhile 4000 works fine, Cpu,temp pcb, rear unit switch have been replaced, since environment conditions were out of spec. you cant really say printer is at fault. Traded out with 4000 months ago it is working fine. We figured in a better environment printer would be fine. I get 4020 to check out for delivery it jams every print at exit, has message of close top cover (different cover) that will not clear, after clearing several jams, powering on/off printer finally works. I know operating environment was out of spec. but I don't think that was the problem. Any ideas? Thanks.

We have seen in the past where incorrect paper size/setting in cassette can cause jamming either in the cassette or in the Paper Exit; check Size Dial on front of cassette and be sure it is set to the correct size. Also, check the paper path and verify that a piece of paper hasn't gotten stuck.

Regarding the top cover error, open the cover and verify the sensor is directly below the opening; it can get pushed to the side, if this has happened remove the top and left side covers and repair accordingly.

Are you still getting the "Close Rear Unit" error? If so, check the metal tab on the bottom of the fuser rail, and be sure that it is straight up and down (when looking from side), if it is slightly bent backwards, you will get the Close Rear Unit error continuously.

Hope this helps

[Donnie]

Re: FS-4020dn Close rear unit message

Thanks for the reply, I have checked paper size and actuator, they are correct. My own observations are that the machine jams first print after being off for a long period of time. It has happened 2 days in a row now. Cover open messages may or may not have anything to do with problem. I dont think environment temps are the issue. Maybe power supply or engine pcb? Service manager says fuser has been replaced but i cant find any record of that.

[HenryT2]

Re: FS-4020dn Close rear unit message

This will sound very odd ... BUT ...
One of our tech's had a ' close rear unit ' error that was corrected by replacing the DRIVE UNIT .
SERIOUSLY !!!!!
I KNOW ... We said the same thing !!!!
The only thing we can think is that a solenoid or clutch was somehow messing up the 24v line and causing this error.
If you want to try that ... let us know if that worked for you .

[JustManuals]

Re: FS-4020dn Close rear unit message

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[Donnie]

Re: FS-4020dn Close rear unit message

Thank you for the info, do you know if the message was constant , from what I understand this message could not be duplicated until room temp was lowered below specs. It was in a warehouse or guard shack I think . I have not seen that particular message. At power up it jammed twice at exit unit ,lead edge was almost out , then it said close top cover and would not clear until power on/off . It was working fine the afternoon before. It may work fine when I put it all back together? But I will look at the drive pack. Thanks again.

[Donnie]

Re: FS-4020dn Close rear unit message

ll
reassembled machine, jammed first print, if I carefully remove dev unit, reg sw actuator is sticking, that is jamming problem. I have adjusted top cover microswitch so far so good. These problems were probably interjected. Machine has been dis-assembled several times in past for troubleshooting rear cover message. As of now this case is closed. Thank you.

[Has Been]

Re: FS-4020dn Close rear unit message

Look for tiny scraps of paper in the fuser plug. Drove me nuts for a half hour.