mpc 4500 faded prints. k only!

[ash_572]

i have a mpc4500. keep getting light prints on black only. the fading is in the middle of the paper but the fading varies sumtimes. other coloursprints are perfectly. ive replaced the pcu, transfer unit, black toner and cleaned the ID sensors. still the same. wat can it be?

have also cleaned the laser glass.

[schooltech]

Did you replace all of these items at the same time or were they replaced individually?

Did any of the items temporarily fix the problem? I'm surprised that replacing the PCU, given the fact that it was a PCU-related problem, didn't fix the problem.

What to your SMC printout readings state? You should have some td, id, vsg, vsp, etc, readings related to your copy quality. What are all of those readings compared to the default settings?

With the newer machines, especially with problems like this, what do your readings show? Let the troubleshooting specs in the machine do much of the work for you, as it can help you figure out what the machine IS doing right, rather than what the machine ISN'T doing right.

You might want to double check your K receptacle, to make sure it's all clean, although if it wasn't clean I'd be surprised that a code wasn't thrown.

Is the firmware up-to-date?

[iMind]

You can try engine clear and reprogram the machine from your SMC prints, if this does not work change the eeprom on the main board and reprogram from SMC.

eeprom part #1407-6362

I´ve had some problems with this: faint image, faint strikes 5cm wide in main scan, faint image on the edges in Long Edge Feed.

[ash_572]

these items were replace individually. pcu did not make any difference.

all readings in service are set to default nothing has been changed by a user.

wats a troubleshooting spec? how is it done?
also wats a k receptacle? cheers

[Fearless V K]

When you replaced the PCU did you only replace the Drum section, or was the development unit replaced as well? If you did not replace the development section, I suspect your problem may lie there.

[mrgoodcopy]

A dirty mirror motor will sometime cause faded images. Inspect the mirrors on the motor, when it turns dust will collect on the edge and couse all kinds of weird copy quality issues.:)

[ash_572]

i replaced the whole pcu including the developer aswell.

[schooltech]

these items were replace individually. pcu did not make any difference.

all readings in service are set to default nothing has been changed by a user.

wats a troubleshooting spec? how is it done?
also wats a k receptacle? cheers


I consider the 'troubleshooting specs' as the td & id voltages and all vsp, vsg, vref settings. From these readings, you'll get a good idea as what's going on from the drum/dv sections.

The K receptacle would be the plug for the k pcu unit on the machine end. They can get crap in there from residual 'stuff' and cause issues.

As Fearless asks, was the dv assembly swapped out? You didn't specify that, so I assumed all was well. If you didn't, you might have a doctor blade buildup issue or a slight toner supply issue. If there is a toner supply issue, the td voltage should raise. I initially overlooked the dv unit.



I just missed posting before you replied with the dv post........

[ash_572]

this receptacle plub in the machine end. does it look like an rj45 socket or isit sumfin else?

this prints have improved alot now since av changed the toner bottle and also have given ita a good vac from the inside. but there is still a slight faint black 1 in 5.

[TonerMunkeh]

Pound to a penny that's the laser shutter. These things and their little brother have been an arse for it. Update the firmware to the latest levels, if that fails to cure it take the laser unit out, remove the shutter and then run the machine. I'm willing to bet that's your culprit.

[iMind]

I also change the PCU and development unit and only the eeprom solved the problem, and all I can say is that this is my fourth machine with this problem, three of them where solved with engine clear.

[Ollie1981]

I'm putting money on the laser shutter, Toner Munkeh is right, I've had a couple of these do weird light copy things due to the laser shutter timing issue.

Check the firmware on the machine, make sure you're using the latest Engine firmware (then make sure you update all other firmware to the latest levels, there's literally pages and pages of weird crap that can happen with mismatched firmware levels on our in-house discussion board, paricularly with the Katanas)

There is another outside possibility. On the Kir (1015/1018) I have had uneven image density problems due to the developer auger gears being destroyed by dev getting into them. But this would also cause toner spillage and "Add Toner" messages.

[ash_572]

nice one. afterall it was the laser shutter. av only bin in the industry for 15 months. had engineers with 20 yrs of experience tryna figure this one out lol:D

[iMind]

Thanks for feedback, always learning, now I´m wondering maybe when I memory clear the engine it resets the shutter motor timing, I´ll try this one next time it happens.