Riso GR3770 paper elevator stuck?

beau_house · 08-07-2009

My Risograph GR3700 was shut down for several days without the paper elevator being closed properly (it was left loaded with paper and the elevator was raised). When I removed the paper and brought it back online I received a "check paper feed area" message that does not clear and the feed tray lower button no longer works. There is no paper left anywhere in the feed area, and I have tried moving the safety switches above and below the paper tray to no avail. Since everything worked fine prior to powering down, I find it hard to believe that the safety switch could be faulty, although anything is possible.

I am at a troubleshooting dead end here. Is there something obvious that I am missing? Any suggestions would be greatly appreciated.

beau_house · 08-09-2009

So I thought I would give an update on my problem for anyone that might be following this thread. Sequential operation test 102 (elevator position) will not run (I'm assuming) because of the "check paper feed area" error message. Running test 40 (checking the state of the paper feed safety switch) indicates detection with a .1 second interval beep. According to the technical manual, this means that the switch is detached "for any abnormality occurrence". I'm assuming that's bad, but I could be interpreting the status incorrectly.

At this point, my best guess is that the safety switched is to blame. I may try to detach the wire harness that is connected to the switch, but because the elevator is almost fully raised, I don't think I'll be able to access it easily.

Has anyone seen a problem like this before? Is there a way to reset this switch that I am missing? Or perhaps another way to disconnect it to verify that it is truly the fault?

**joelsa12** · 08-10-2009

On the paper try you will see a cable underneath it. I suspect with the tray in the up position that someone of some thing has come by and pulled this out of the machine. Make sure that it is plugged in properly. Also follow this wire to the back of the machine. Make sure that it is plugged in by the feed clutch and also make sure that all connectors on the board on the top right are all plugged in. If that is all good, pull off the front cover and make sure that none of the fuses are blown. It the signal line fuse is blown you will get a fast beep when checking the sensor. Take canned air and blow the switches out. I have see paper dust cause them to trip. If all of this has failed then yes you have a bad switch. Take them out and check them with meter to know which one exactly. You can pull the elevator motor off the back of the machine to get the tray in the down position if you must.

beau_house · 08-11-2009

First off thanks for the recommendations. I checked the cable underneath the paper tray and followed it to the back of the machine (as far as I could see, everything is all right). The connectors on the top right board are properly secured as well. I also took off the front panel and visually inspected fuses 1-7, they checked out fine, although I do still get a fast beep when checking the sensor. In order to lower the paper tray I took off (then reattached) the elevator rack on each side. That made it much easier to remove the pickup roller cover and access the switches. I tested them with my Multimeter and neither one is faulty.

I'm stumped again. Is there a third switch under the feed tray that might be the cause of a "check paper feed area" message? I'm not entirely sure how and why that switch gets activated. Thanks again for the suggestions. When I progress further I'll post another update.

**joelsa12** · 08-11-2009

There is a switch on the under side of the paper tray. It is there incase someone would have their had under the tray as it comes down. There should be a bar acrossed the bottom that moves up and down. I believe that this switch is always pressed. i have seen paper get stuck down there and cause this bar to open the switch. Once again I would check this with your meter and make sure that it is working properly. There are 2 three mm allen screws that hold the tray on. take those off and the tray will come right out. remove connector and the tray will be in your hands. good luck.

beau_house · 08-12-2009

So I detached the tray, tested the switch, and it was fine. However, I did discover that the metal bar at the bottom wasn't pressing the switch (as you said it should) in its normal position. Somehow the metal plate that the switch is mounted on was bent so that the bar wasn't fully making contact with the switch. I persuaded it back into position and that cleared the fault.

Thank you so much for taking the time to respond to my posts. I wouldn't have been able to fix this without your help.

Sincerely,

Beau House