Riso FR 2950 hook lever won't catch pressure lever. Sheet dead under drum.

[edparham]

Riso FR2950. Had been making good prints. Stopped three sheets into last press run and is still down.

Found that the hook lever has proper up-down action but will not move forward to catch the pressure lever (it will activate for a second about midway through the sequence but on a down cycle, so it doesn't catch the lever).

The result is a flat-out sheet dead below the drum.

The pressure solenoid tests good. So does pressure motor (though I had to test it on a GR; the FR manual doesn't have a test code for it). The pressure disk is properly oriented.

Any suggestions? Thanks.

[RRodgers]

You've double checked your timing?

[edparham]

Thanks for responding.

Sorry, but I don't know how to check the timing (wish I did). I'm not a tech, just a guy with a screwdriver and a flashlight. And a junked GR machine. And a set of Riso technical manuals on CD with garbled chapters having to do with the FR pressure roller (I went to the GR manual assuming there's not much difference in them).

Any help would be appreciated.

[joelsa12]

the test mode to test the solenoid is test mode 68. i would turn it on and the hook should fire. go to the back of the machine and shake the solenoid wire ( black and red with plastic around it. the up and down motion of the pressure assembly has been know to work the wire to the solenoid so much that it will break. also between the timing and guide rollers there is your paper sensor ( indise of where the drum is) I have see paper or even a piece of used master material sitting in front of this sensor to cause your issue. but like mentioned I would check the timing first. you can tell by the two disk on the back. the one on the left should have the hole right in the middile of the sensor and the one on the left should have the timing mark right below the sensor.

[edparham]

Thanks for responding, joelsa12.

The pressure solenoid tests good. No wire fatigue evident.

Paper sensor likewise tests properly.

The two disks are where it gets interesting. As I said, the pressure disk is aligned properly. Not until after reading your post and consulting the (GR) manual did I realize the P disc is flipped. The alignment notch and hole are 180 degrees opposite where they should be.

The manual says to loosen some allen screws and crank-turn the timing roller shaft to adjust, but I don't see how those directions synch the P disk with the pressure disk. Shouldn't I instead crank the guide roller shaft into position?

Please advise. Thanks.

[RRodgers]

There is a timing mark (hole) for the pulley just under that right P disk. Should be at about the 5 o clock postion (if I remember right) The timing mark for the center pulley points at 12 o clock (once again if I remember right) I really need to pop the cover off a Riso and have a look, it's been years.

[joelsa12]

you can only check if it is timed properly when the drum is in the home position. button up the machine. you can leave the back off. put in a drum and press the green button on the front by the drum and this will home the drum to position A. once that is done look at the disks on the back and see if they are where they need to be. if it is out of time the one on the left hand side (pressure disk) should be lined up with the whole right in the middle of the sensor and the one on the right (paper feed disk) will be off. this would cause your issues. another thing that you may check is if your timing and guide rollers are functioning properly. i have seen the sector gear which drives the timing and guide get in a bind. it will not come back to its home position after it feeds a few sheets. the one way gear on the end of the guide roller ends up being the cause of this. keep us posted

[edparham]

Thanks, RRodgers and joelsa12. Joel, I assume you're pulling for Butler in the big game tonight.

RR, about those alignment holes in the P disc: there are two of them, and which one you choose depends on the drum width (mine's legal-size).

Pulled out drum. Inside the machine I can put a finger on timing roller and rotate it clockwise (one-way only). The guide roller thus rotates counterclockwise. I can see both the guide and timing roller gears at the back end rotating in tandem.

This might be a (the) problem. Where the guide roller shaft exits the back wall of the machine’s main body and terminates, there is another gear IDed as a guide roller gear, and it is tooth-to-tooth with and below the sector gear. Being able to rotate the guide roller shaft, of course, means that it is rotating freely inside this second “guide roller gear,” since neither it nor the sector gear is moving. This may be by design — or not; I don’t know.

I have located instructions in the manual on releasing tension of the main belt so that the cam pulley (and P disc) can be rotated into correct position (you loosen the paper feed clutch and turn it clockwise). I’m about to attempt this operation. Will report back later.

[edparham]

Success! It took a while to figure out how to get a grip on that gear behind the P disk to turn it, and getting the P disk oriented without also moving the pressure disk was tricky until I jammed a small Phillips screwdriver into the pressure disk's alignment hole (after first hitting the green button inside the front cover to get the drum to home position, which was convenient).

Result: printed off a 100 sheets, good as before.

Thanks for all your advice and support!

[mikadonovan]

I have to say for a guy with a screwdriver and a flashlight you did pretty good. Even with the excellent advice given in the thread, 99 non-techs out of 100 still wouldn't have gotten it fixed. I'm impressed.