GR3770 image printing short

[smallprintds]

I have a GR3770 that has a problem that is driving me crazy. I've looked over other threads and I haven't seen any that answer my question, with that said...

I can't make one of my machines print more than about 15 inches of what should be at least 16.5 inches image area. What happens is the print starts about 1.5 inches late on the paper... I've checked my master and it's the proper size, the machine just starts the print late on the paper. I've fooled around with a mess o' things and I can't seem to find an adjustment that moves the image in the direction I want it to go (other than the machine's fine tuning adjustment)

I've messed with the timing cams, and those don't do much... I can make it worse adjusting those, but I can't make the image move in the direction it needs to go.

Any gurus out there who have an easy fix for this? Or even a hard fix would be ok at this point

Thanks
DaveS

[smallprintds]

If at first you don't succeed try, try again... you'll either fix it or break it so bad it can't be fixed, and that's kind of a fix too.

I wonder if I've got a belt off a tooth or something weird like that? I'm not sure the belt would make a difference with one of these things?

Regardless of belts, I believe I have the problem fixed... or at least it seems fixed, I haven't put many copies thru the beast and that's how you really know, right?

I was able to move the image by adjusting the sensing wheel on the right side so the notch is 3/8th of an inch ABOVE the sensor... much further and it throws the timing off and you get paper stuck to the print drum.

Thankfully I don't work on these much... and that's why I don't know the proper names for these things I mess with. Sorry about that, I know it makes it hard to understand exactly what I did and whether that would work in another situation... What really sucks (for me) is half the time I forget how to fix the problem the next time it occurs. Which is both good and bad; bad because I have to re-learn how I fixed it the last time, but good because it means I'm not always working on my Riso

I love'em when they're working... not so much when they're not.

I hope this might help someone else. And if you read this and think what I've done is stupid and there is another way to do what I did, please let me know

Peace
Dave

[20gaugeO/U]

Loosen the 3 gold screws on the base of the feed clutch. Unhook the silver spring on it. Move the belt a tooth or two over the timing cam. Reconnect spring and tighten screws and hit test print. It sounds like you are flying blind, do you have a book for this to see what you are adjusting? The main belt will stretch over time and copies so good luck.

[smallprintds]

I have a 'kinda' manual and a 'kinda' schematic outline I bought off ebay a few years ago. Neither are very good, but they're better than nothing. But do I have the equivalent of a Chilton's Manual? Nope, unfortunately I am more or less flying blind when I find a jam... Fortunately my father was a mechanical genius and taught me quite a bit about how to problem solve machines so that helps... I just wish I had his ability to 'see' problems. Sigh.

I appreciate the advice... I might give it a try (I had the belt loosened once already – you wouldn't believe what I went thru the other day

I think I have it 'fixed' but maybe not... I haven't put it to the real test yet. I'm going to wait until I've fixed my other 3770 and then worry about dialing-in the machine this thread is about.

I need to replace Gear "A" and Gear "B" on the other 3770, hopefully I have a couple on order. But I'd be interested knowing a good source for parts if anyone has a line on that.

Thanks for the reply 20gaugeU/O

Dave