Resolved Issue With MPC5501 Black Marks

[engineers]

IMG_20141030_154544.jpg

As in image, black marks in centre of page roughly 4cm apart reoccurring sometimes darker than others.
First thought was dev unit, luckily had another machine so could swap everything over, dev/pcu/itb/ptr/fuser just tried all units as they were there, no change.
Then went for dev clutch, no change. The marks are on the ITB so must be on the pcu, so looked at the connectors and checked grounding etc.

Anyway left it until last, engine clear and sorted.

Just in case anyone runs into the same thing

[SargeNZ]

Was this on copies or prints or what? An engine clear is kinda drastic....

[slimslob]

IMG_20141030_154544.jpg

As in image, black marks in centre of page roughly 4cm apart reoccurring sometimes darker than others.
First thought was dev unit, luckily had another machine so could swap everything over, dev/pcu/itb/ptr/fuser just tried all units as they were there, no change.
Then went for dev clutch, no change. The marks are on the ITB so must be on the pcu, so looked at the connectors and checked grounding etc.

Anyway left it until last, engine clear and sorted.

Just in case anyone runs into the same thing

Next time please provide some indication as to the direction of paper travel.

Was this on copies or prints or what? An engine clear is kinda drastic....

The sample in the picture is a system SP mode test pattern.

[engineers]

That copy was done through copy screen in SP mode, just a blank copy off the glass. LEF.
Was both prints and copies, was worse if doing a counter straight after a sky shot.
It is resolved and working fine, put values back in from birth certificate etc.

You are right with a memory clear being drastic, it was either that or boards to try next. I didn't have any boards to spare so went that direction.
Usually if done correctly I don't run into any adverse effects, but I do leave it to one of my last options.