Cause/Solution |
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- No vacuum at the cups at all:
- Check if there is vacuum at the vacuum generator. Disconnect the line at the generator and measure/check for vacuum.
If there is no vacuum, check the pressure at the inlet to the vacuum generator and make sure it is high enough.
- Cover all the cups on the same manifold to see if vacuum is generated when they are all covered. If there is,
there is likely a single bad cup with a missing orifice or the cup is not making a good seal with the manifold. Isolate
and replace the bad cup.
- Check if there is vacuum at the connection point to the lines from the registration bar. Disconnect the quick fittings
and check for vacuum. If there is vacuum at the connection point but not at the cups, there is likely a problem within
the registration bar. Remove and inspect the registration bar components.
- One vacuum cup is not working:
The easiest way to determine if the cups are working is to cut a small piece of printing plate larger than the outside
diameter of the cup and test each cup individually for vacuum. In service shell, type punch cups up and wait
for the command to complete. This will raise the cups. Then type punch cups vac on to turn on the vacuum
generator to the cups. Take the plate and cover the first cup, it should draw down relatively quickly (around 1 second)
and make a good seal. To release the plate, cover the exhaust port of the vacuum generator with your finger temporarily.
You will notice that the vacuum reduces and you can take the plate off the cup. Then you can repeat for the next cup and
so on.
- Remove the vacuum cup by itself by pulling it off the barbed stem with a twisting motion—be careful not to rip the cup in doing so.
- Replace with a different cup and re-check to see if the cup was defective and the leak has now gone away.
- If not, remove the cup again and then remove the cup mount. This is done by using pliers or a similar tool with a rag
or similar on its jaws to aid in protecting the aluminum vacuum cup mount’s barbed surface. Inspect the cup mount to
ensure it has Teflon tape and that the orifice is not clogged or missing.
- All the cups on one manifold leak.
- Likely, the vacuum line fittings or the end plugs are leaking. This can only be diagnosed by removing the
registration bar.
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Registration bar removal |
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To troubleshoot mechanisms inside the registration bar, you must remove the registration bar and plate deflector assembly
(500-03541A). To do this:
- Disconnect all the tubes and the cable going to the plate sensor inside the sheet metal. There are 3 M5 screws on each
side with Belleville washers that fasten the sheet metal side flanges of the deflector to the steel side plates of the tilting
side registration mechanism 500-03542A. Note: there is a single short screw on each side near the pivot that is required for
clearance issues. It is a long piece and is best removed with 2 people, however, this can be done by one person if you put some
foam underneath the part while disconnecting each side and then removing it while supporting it evenly.
- Once the assembly has been removed, place it on a suitable surface for further disassembly/troubleshooting.
- The registration bar can be removed by taking out the two M4 screws that mount the rod ends of the registration bar actuation
cylinders to the registration bar (there are two access holes on the top of the registration bar to do this). Once the screws are
removed, the registration bar can be pulled away from the cylinders and rotated up and out of the deflector pan sheet metal.
Flip the bar over and all the components can be accessed from this orientation.
Installation is the reverse of removal. To maintain the smooth operation of the registration bar, it is important to ensure
that the cables and tubes are reattached and strain relieved as before.
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