OS Guide pulls on the return course

Discussion in 'Heidelberg Printing Presses' started by Dave Wolf, Nov 7, 2016.

  1. Dave Wolf

    Dave Wolf Member

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    Location:
    Quebec, Canada
    I've seen another post somewhere where someone had the same problem, the side register guide on our CD74 (2010) on the OS continues to pull as it returns to its beginning position. We have to turn the pressure way down, below 1.2 bar, to remedy the situation. We had a tech come and check the timing, said all was good, and it was, briefly. A week later started doing the same thing again.
     
  2. exheidmech

    exheidmech Senior Member

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    Dave,

    Really this can only be caused by a couple of things. Since the turning valve that turns on/off the vacuum to the side guide and the part that actually moves the side guide left and right is the same part (turning valve for the air and cam for the side guide movment) it should be pretty easy to find the issue. One thing to check is this drive shaft, you will need to remove the inner bellows to see this shaft. It has 2 "key ways", one that runs the length of each side of the shaft. This double keyed shaft goes through a plastic plate on each guide that also has 2 plastic tabs or "keys" that slide through the keyed part of the drive shaft. Very common for these plastic tabs to be worn out or broken off especially on the commonly used side guide. If these are broken, they are pretty easy to replace, just getting the side guide timing reset can be tricky. If these are ok then most likely you need to actually replace the turning valve in the side guide itself.
     
  3. jmt

    jmt Senior Member

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    http://www.colorprintingforum.com/h...-74-2005-suction-pull-guide-problem-3930.html

    is this the problem you are talking about?

    we never did find the problem ran for years with this headache. Heidelberg wanted to replace the whole pull guide . the penny pinchers didn't like the cost and of course we where still running.so I have been doing a lot of cleaning of the lines the pull guide and anything else I could find that would help but never did. than about 6 months ago I did my usual cleaning and bang issue gone. so I don't know what happened but it is pulling fine now. I also did try to advance the feeder timing a bit to get the sheet there a bit earlier it did help some of the times but of course will cause other problems.
     

  4. Dave Wolf

    Dave Wolf Member

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    Location:
    Quebec, Canada
    If and when I can get some time, I'll check it out, thanks for the info and I'll let you know if I find the problem.
     
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