Toshiba Studio 2540 CE20, CE40, C970

[jesterace]

Hello we have this toshiba machine that has been fine until all of a sudden it started having blurry print (I haven't seen the defect, one of my colleagues did, but shortly after it came up with a service call error C970).

I'm not a printer expert but do plenty of electronic repairs and we have been taking a look ourselves.

On first inspection it showed C970 which i understand to be high voltage transformer issue. After removing toner, drums, transfer belt and cleaning and reinstalling we got a mix between CE20 and CE40. C970 would occasionally come up but mostly its been CE20 and CE40. We have been referring to service manual. We can see that the printer is printing a striped test pattern on the transfer belt in the middle and all colours are present on that but I haven't got an example to compare with to see if it's absolutely right. We checked the toothed wire and grids on each drum and they are pretty clean and nothing broken. High voltage tab/springs on each drum and inside the machine look good. There appears to be a nice even coating of toner/developer on the developer rollers of each drum unit. Everything moves freely. Waste toner box clear, transfer belt cleaner is clear. We have cleaned the image quality and alignment sensors and tested that the shutter opens and closes from the test mode.

We got to the point where we didn't know where to go next but I found in the service manual that there was a code to essentially bypass the image quality checks, and it showed that a test print could then be done in 04 mode (possibly code 127 if i remember?). To my surprise it printed off a few sheets. It contained a colour bar with CMYK but the black was awful. There was a square black blotch in the middle of the sheet and a thick dirty/smudgy horizontal black bar at the top of the page. When i then looked at all the drums, the black drum still had a thick stripe of toner adhered to it. All other toners were clean. This stripe coincides with the defect on the paper. I tried cleaning the black drum but the defect persisted and the toner still got left on the drum afterwards.

Shortly after we got the C970 error again and couldn't even do this test page in 04 mode with image check bypassed.

I then removed the black drum and 04 mode loaded without error.

Does this sound like a bad black drum? Is there anything else i should check?

Thanks,
James.

[blackcat4866]

The C970 is almost always caused by a shorting primary charge unit, which will coincide with your image quality issue ... so black. Often the post that the spring or grid attach to snaps off, but the primary charge unit itself could be shorted. If you want to be sure, swap the primary charge with that of another color, and see if your image quality issue follows.

Is the toner on the black drum fused to the drum surface, or just sitting there loose? If its adhered, the clearcoat on the drum is worn through, and will continue to adhere. If the toner is loose, it may just be a worn drum cleaning blade.

The CE20 & CE40 are just the inability for the machine to self calibrate due to poor image quality of one of the colors.

It would help to see the image quality defect.

Keep in mind that this machine has been obsolete for a while now, and will be difficult to find parts.

[jesterace]

Hi i have took some photos of the test prints that the printer gave me in 04 mode with image quality checks bypassed. I was wrong when i said horizontal black bars/smudges it was actually vertical as shown.

http://www.jmcomputers.co.uk/dump/pu...810_072746.jpg
http://www.jmcomputers.co.uk/dump/pu...810_072752.jpg
http://www.jmcomputers.co.uk/dump/pu...810_072802.jpg

Would appreciate any feedback about these prints as i'm not sure what a correct one looks like.

The toner left on the black drum was not adhered. I could wipe it off gently with a cloth. I've done that a couple of times but it just builds up again.

The surface of the drums all look decent. Is there anyway i can check to see about the short circuit on the drum? Will this be visual or can it be checked with a multimeter at all? Since at the moment we don't have any spare drums to do any part swapping. I have brought the black drum home with me to take apart and assess further.

Thanks again for your help with this.
James.

[blackcat4866]

If you think it's the drum, swap that drum to another unit, say magenta, and see if the quality issue becomes magenta.

What did you not understand about swapping the primary charge unit to another drum unit? =^..^=

[jesterace]

Hi I understand what you're saying, but..

I just didn't see how moving a charge unit around was going to tell me where the issue is (with regard c970). If it just gave me c970 again which it most likely will eventually then I'm no better off. Yes I can swap drums around between print units to determine if a particular drum is causing bad image quality but I just wondered if there was a way of checking for a charge unit fault on black. If I had a spare then it wouldn't be a issue. Unless of course the printer will allow me to do a test print with a print unit removed?

If I'm over complicating things I'm sorry. Just thought someone might know how to test the drum charger for a short. Seemed like the logical thing to do to that's all.


I guess I better hunt for a drum but I just wanted some confirmation I was on the right track.
Thanks,
James.

[blackcat4866]

Hi I understand what you're saying, but..

I just didn't see how moving a charge unit around was going to tell me where the issue is (with regard c970). If it just gave me c970 again which it most likely will eventually then I'm no better off...

Sure, you'll still get a C970 ... and those bars crossfeed will have become magenta, or cyan, or yellow, depending on where you move that charge unit.

... Yes I can swap drums around between print units to determine if a particular drum is causing bad image quality but I just wondered if there was a way of checking for a charge unit fault on black. If I had a spare then it wouldn't be a issue ...

That is going to be the main problem. Any kind of spares will be hard to get.

... Unless of course the printer will allow me to do a test print with a print unit removed? ...

No it won't print with an imaging unit removed.

Hey, I'm just trying to point you in the right direction. If you don't like my advice, please don't take it.
Oh, one more thing. I hope you've been keeping that drum unit in the dark. Drums will light shock if left out in room light.

=^..^=

[Rusty.Harris]

Take a close look at the plastic inside the charge units. If you see what looks like a white line sort of looking like a lightning bolt,
replace the charge blocks. Those older machines were pretty bad about the ozone screwing up the plastic and then making a
nice little white line all the way to the metal attachment screw. Especially if the assembly at the production of the machine, they
over tightened the screw, cracking the plastic.
As mentioned before, swapping the charge corona to another color EPU would be a good way to trace it down.

[jesterace]

All the info is greatly appreciated and nobody should ever think that I'm not taking their advice. I know these places can easy start fires when people who have knowledge get challenged by people who don't, but I know my place. I'm just asking questions and not judging anyone's advice. People on here are far far more experienced than I am which is why I'm here, but that doesn't mean I won't ask questions about something if it's not taking me closer to the root of the problem which is where I want to heading. We don't have the luxury to part swap with spares. We have kept the black drum in darkness and others have been covered up when out of the machine. I have the black EPU in front of me here and the printer is on another site, so this is why it's handy for me to know what potential defects to look for on the EPU.

To update we have tried swapping the charge units around between black and one colour but at present we can't shift the C970 popping up again. The only way it goes away in 04 mode is if we leave the black (or the EPU with the black charge unit installed) left out.

We will take a look at the plastic also as suggested. I could take some pictures of the black EPU disassembled if anyone would be kind enough to run their eyes over them?

Thanks again,
James.