GR3770 feed

[sscottsr]

I have a 3770 that won't pull paper through the machine. The initial pick up of the paper works fine (I have just replaced the first section — tires, etc., too) and everything was working fine for several thousand copies. The first sign something was wrong was that the first sheet (and only the first sheet) after making a new master would not go through, but would "accordion" the sheet. After removing that sheet, everything would work as normal — never even a misfeed. However, now, suddenly, no sheets whatever will go through the machine. There is no "accordion" issue, but the sheets stop after passing past the feed tires with a paper jam error (under the drum). The sheet is not really jammed, but is just laying loose. I'm guessing something with the "interior" feed roller even though it seems to move appropriately. What should I check, clean, remove, etc.?

[joelsa12]

If is is accordian folding it makes me believe that there is an obstruction of some king. I would bet that the buckle sheet has cracked and is causing your problem, but that is only a guess. If you can pull out the feed tires with the e-clip toward the front of the machine you will be able to look in there. You will see a piece of plastic sticking out, that is the buckle sheet. The paper feeds to the rollers after this sheet and buckles to get your registration. See if there are any obstructions in the small gap that the paper goes through, and also check with a flash light theintegrity of this sheet.

[sscottsr]

Checked the buckle sheet already, but I checked again after your post to see if I had missed anything. No obstructions, no bends, no cracks. Another tech came yesterday and spent about three hours with the machine, too, in case I missed something (which I obviously have done). But, no go. He is at a total loss, too. We re-adjusted, re-checked, re-cleaned everything and it just won't work. By the way, we did see that the paper clears the buckle sheet area and appears to be stopping at the interior feed (registration) roller. But, the roller, gear, spring, etc. all are within spec and seem to function properly. The paper just stops and the machine errors out right after the lead edge of the paper clears the registration roller. Could the sensors be playing some kind of trick? Any other ideas? Thanks for the input.

[joelsa12]

Your machine is saying jam under drum. There are two sensors on the receiving section that kick this out. Make sure the covers are clean, the sensors will be next to the middle belt on the transport. This will give you a jam under drum even though there is not one. The other thing would be to take off the cover to the timing and guide rollers from the inside of the machine. I have seen mastermaterial that was supposed to go in the disposal sensor fall down in here. It gets in front of the paper sensor and causes the same proble. when you take off the cover there will be a space in the metal roller that is going acrossed and this is where the paper/master would be. Lastly is the machine timed properly?

[bannerju]

My 3770 does the same thing. It is annoying, but cheap to repair. Pull out the accordian and keep on truckin.

[mikadonovan]

My 3770 does the same thing. It is annoying, but cheap to repair. Pull out the accordian and keep on truckin.

That is not a repair. It is simply ignoring the fact that there is a feed problem that needs to be addressed.

[bannerju]

That is not a repair. It is simply ignoring the fact that there is a feed problem that needs to be addressed.

I apologize if that sounded like a smart-a answer, it wasn't intended that way. its just how I handle the jam.
Do you have a source for stripper pads for that machine?

[sscottsr]

I want to thank all for the posts. The machine in question is still unusable, so any additional posts would be appreciated. We finally took apart just about everything - clutches, etc. - but no change. By the way, the "accordion" paper issue was just the first thing noticed - it no longer does that, it just won't feed at all once it enters the machine. Every once in a while, as I walk past the machine, I just push print to see what it will do without making any adjustments [my really scientific approach ]. Once, it made 48 prints, and another time Craig got 198 prints, but then it went right back to no complete feeding of the paper with the jam under drum error. Mechanically, this makes no sense at all. The sensors check OK, but could it be some other electronic issue causing it to "shut down"?

As for pads, I don't have a good source, either, but I have used some for other machines from time to time. The pad on this machine is NOS pad I already had and just put on.

Thanks again.

[The Doctor]

Have you checked the "Stacker Switch" which is located in the stripper unit. It is designed to stop multi papers being fed thru the Riso which could result in the timing to jump out. When the stacker switch is activated it stops supply of 24VDC to the paper feed clutch. Worth a check!! Best way too isolate it is to adjust the stacker switch all the way down so it won't be activated.
Hope this helps.

[20gaugeO/U]

1)I agree with the stacker switch (disable with locktight on the screw).

2)Also recheck the timing lever gap. I use a 3mm allen wrench and put pressure on it to the gap tightens up a hair when the wrench is removed.

3)Test the paper IN sensor (TM #6) by taking and strip of paper and sliding it quickly in and out from the paper IN sensor opening. When this sensor is failing it will beep erradically (a couple of quick beeps, pause, beep, pause, pause, beep). It will test fine if you just slide a piece in there and leave it lay.

4)Replace the feed tire cores. The one way bearings will fail after a couple million.

5) Replace the two one-way load springs on the guide roller and oil them up.

Good Luck!