GR 3770 Timing Issue - Please Help!

[fantasyboytaro]

Having an issue with my GR 3770 after putting in an untested drum that apparently was messed up , when trying to make a master it got stuck and made a pretty nasty sound. This caused new master to be off by 12mm. Reading the forum and using the GR Technical Manual , section I-38 arrangement of cam and main pulley, we were able to get the print to align closer to the original (scanned document) to only be around 6mm off.

Getting it to this point was pretty difficult for us, as we originally were, after rotating the paper feeding clutch to loosen the belt, disengaging the belt, we were using out hands to manually rotate the pulley (crazy hard), so after failing at that and making it worse, we learned to use the little brown button on the motherboard to rotate the gears. (Figure 1 Dropbox - FigureOne.jpg - Simplify your life ) is this incorrect to use? Should we be "muscling it" or should it not be so difficult to rotate once the belt is disengaged?

So as I stated before, we were able to get the print to be only 6mm off (for some reason it also became horizontally off as well), the cam and main pulley adjustments were made while the red drum was in the machine. However, I tried to make another master with a green drum and it was back to being 12mm off again. This kind of stumps me...
Is it possible we made adjustments to a drum that was itself out of synch as well? Do the drums need retiming as well? Both of the drums had been used before the machine was having issues with no problems, so I dont really think the drums are the issue. Has anyone else had this issue.

I am attaching 2 more photographs, figure 2 ( Dropbox - FigureTwo.jpg - Simplify your life )
and figure 3 ( Dropbox - FigureThree.jpg - Simplify your life )

These are of the back panel, do they look correct? In figure 2, I have a part circled that i am guessing is the "35 011-11255-004 Pressure Sensor Disc" , which looks to me to be in the incorrect position.

In figure 3, I am trying to show the alignment of the main shaft plate and cam pulley.

So since the red drum is only 6mm off, I'm thinking we need to move towards adjusting the guide roller cam (I-37 in the GR Technical Manual) or should we tweak our position on GR Technical Manual , section I-38 arrangement of cam and main pulley again?

Please please please any help or wisdom would be greatly appreciated. Also if anyone knows how to make these adjustments and could guide someone over skype or facetime I would super be down for that and can venmo or paypal you for your time.

Also sorry for using dropbox links for the images, I couldnt get them to upload on the thread for some reason.

Fingers Crossed,
Taro

[jermyth]

Shouldn't have used the button. Looks (but I haven't been in a GR for a long time) like the timing is all off. If you got a manual, follow the directions and pictures and get the main pull and cam pull back to spec. I-38 shows the alignment holes. Then if the image is out of position follow the steps based on how far out it is.

Good luck.

[mwillems]

How are things going ith that part? I really have kind of the same issue aus documented in the facebook group "risograph printing", if you're there.

I really like to get through all of the details to fully understand the way it behaves.