Canon NP 6050

[copydr]

I have a customer that has an old Canon NP 6050 and the copies are coming out blank. The charge corona looks good. Can't pull out drum section to see anything. Any ideas?

[lkrsardis]

6050

a blown exposure lamp will cause a blank copy on these machines.
You have to remove the developer unit to get the drum unit out.

[costd]

You have not given much info so pardon me but - first thing I would do is a sky shot and watch to see if the lamp comes on. No light - blank copy.

Work on the 6050 almost weekly and do not understand why you cannot pull out the AP unit (drum section). Perhaps he was right in that you forgot to remove the developer assembly first. Once you get everything out of the way, the AP unit is held in with just 2 screws. When in doubt - RTFM.

I would not suspect the drum though. Everyone has their own ways but I would check the scan lamp first. If that is working, then set your system to make several copies of your NAI test chart) - then after the first copy, pop the front door (stops the system). Remove the developer and look at the drum to see if it is being written on. Depending on the results, go forward/backward in the copy process (who'd a thunk I listened in class ;-).

[mannu]

remove dp unit and now u pullout drumunit .if carona wire is ok see the hvt unit ......

[blackcat4866]

I'm with Iksardis on this one.....

I'm with Iksardis on this one. Don't make this overly complicated.

If the exposure lamp does not come on there is a problem in the exposure lamp circuit. This can be diagnosed easily. With the power Off & unplugged you can ohm out each component in the exposure lamp circuit. There is always 120VAC present at one of the lamp terminals, even when the lamp is off, even when the machine is off. You can tell by the arc marks on the side of my favorite magnetic screwdriver.

Ohm out each component one at a time. As likelihoods go I'll lay these odds:

1) 85% exposure lamp open
2) 10% optical thermal fuse/switch open
3) 4% lamp harness open
4) 1% who the hell knows.....

[copydr]

Thanks Canon NP 6050

Thanks for the amazing response!!! I am shocked at the fast results, I look forward to giving back in the future.

As for this situation. I will go by the customers again on Monday, The lamp was coming on during the warm up cycle, but I did not specifically check while making a copy, so I know the lamp is good, still could be the harness or something.
I did check the corona units both seemed ok wires not broken and clean.

As for this so called dp unit - how do you disengage it. My Intrivia book said you need a special tool to take out the drum unit out is that correct?

There is also a key counter attached to this machine that the customer wants removed, does anyone have the code to disable that?

Thanks

[costd]

Perhaps it is refering to the drum rotating tool. It is just a plastic knob that is normally kept in the waste toner area. We never use it as the drum shaft key should only be hand tight. Just use a rag to hold it while you unscrew (make sure the drum does not rotate counterclockwise).

[Canuck]

If lamp went,copies would be black at first,then blank when the machine does potential control.Turn off potential control in service mode then run a copy...start by re-wiring all coronas...you said both corona units looked ok...there are three on this machine....i've had the drum screw come loose(drum doesn't turn)and get blank copies.Check the developer drive gear...i've changed a few of them(Dev roller seizes and wipes out dev gears)

[yourownfree]

key counter

the key counter just unplugs, then you have to look at the schematic to see which wires are which to bypass. Usually there is a jumper on a connector that you pull off when you install a key counter. maybe you can just buy that from canon, then you don't have to fuss around with it.
clarification "a connector with a jumper attached"
I never saw anyone mention potential control. Maybe it has gone cuckoo and overriding the system. can turn that off to get rid of one more piece to the puzzle. Rare but..... also what if no transfer is occurring? Maybe pretrans is crapped out. seen that stop transfer current. remove and test. or just primary not engaged all the way in the plugs. then #4 from blackcat

[Canuck]

Do some trouble-shooting..shotgun approaches take longer and are more costly....check Vd and Vl in service mode..if Vd is way low,drum is not being charged(primary)..if ok and lamp comes on,Vl should be ok.If not, check potential control,optics obstruction. If ok,look at transfer currents in service,check transfer wire..pull the cover off the transport and run a copy and see if transfer corona wire glows..if ok,make sure drum is turning..if ok,check developer,dev drive...whats left?Before you do anything..turn off potential control and run a copy..if i get a blank copy call on one of these the first thing that i do is ask customer if copies were black before blank..if they say yes i bring a exp lamp in with me..black copies until machine does potential control again..then blank. 15 minutes of trouble-shooting is easier than 2 hours of shotgun blasts

[mdm7266]

Re: Canon NP 6050 blank copies

help with blank copy canon np6050. Already Jammed the copier in the middle of copying and looked at if there is am image on the surface of the drum. but no image at all. so i conclude that there is no primary charging (no output on primary charging) Developer is ok (rotating as in no broken gears).

What i notice that there is no Primary charging, no output on transfer/separation. (no high pitch sound)

I also notice that when i tried to copy a multiple copies, slowly there will come out an image. It takes to run many copies to create a whole image of the document. So what might be the problem?

Already clean primary charging recaptacle, transfer/separation receptacle and check for high voltage leakages.

Electrical problem? no 24v supply on HVT? (Note: already check HVT boards for Cold solder terminals. HVT ok, because i already swapped it with other machine. i did not yet swap the other parts because it takes miles to go there.

Any more suggestions?

[Brian8506]

Re: Canon NP 6050

Rewire corona units. Change developer clutch.

[yourownfree]

Re: Canon NP 6050 blank copies

help with blank copy canon np6050. Already Jammed the copier in the middle of copying and looked at if there is am image on the surface of the drum. but no image at all. so i conclude that there is no primary charging (no output on primary charging) Developer is ok (rotating as in no broken gears).

What i notice that there is no Primary charging, no output on transfer/separation. (no high pitch sound)

I also notice that when i tried to copy a multiple copies, slowly there will come out an image. It takes to run many copies to create a whole image of the document. So what might be the problem?

Already clean primary charging recaptacle, transfer/separation receptacle and check for high voltage leakages.

Electrical problem? no 24v supply on HVT? (Note: already check HVT boards for Cold solder terminals. HVT ok, because i already swapped it with other machine. i did not yet swap the other parts because it takes miles to go there.

Any more suggestions?

Replace the lamp it is burned out. It controls the charge. look at the ends they will be blackened. Meaning it is gone.

[Brian8506]

Re: Canon NP 6050

He says he's slowly getting an image. Still worth a look at the lamp.

[yourownfree]

Re: Canon NP 6050

He says he's slowly getting an image. Still worth a look at the lamp.

A quick check of the lamp... turn on machine does the lamp light up during initial startup?