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JR2ALTA
08-31-2012, 11:47 PM
I replaced drum and developer at normal interval, immediately afterward problem occurred.


Front side of image has thousands of random white dots on fill of image. Mostly white sheets like counter printout look fine, a gradation chart is terrible. Only a handful of dots on rear side of image (portrait)

I put old drum back on and spots still there.

I will return with Dev unit and more developer.

Any thoughts?

Thanks in advance!

blackcat4866
09-01-2012, 03:00 AM
Check the right door latch hooks, especially the front. The loop at the front of the door may be broken, causing poor transfer (the transfer contact looses electrical connection). Simple Test: Emergency stop the machine with the paper at the drum. If you're getting a well developed latent image then it's definitely transfer. If you hold the door closed the image quality will clean right up.

The fix? I've had very good luck with LPC (large paper clip). Drill a couple of very small holes to attach a loop of LPC to the door. Manipulate your LPC until the latch returns smoothly, fold over the ends, crimp, and secure with superglue.

I don't want to think about what it would take to change out the door. My machine has done 150k since the fix. It seems durable.

The actual contact can become bent also. That was one of the classroom bugs. =^..^=

JR2ALTA
09-01-2012, 03:14 AM
Thanks BC, I failed to mention that I did a stop and the image problem is on the drum.

I also didn't mention that when I ran my TCR the new dust filter was not snapped in on the front side.

But...I don't think that could have done anything to the Dev Unit, as mentioned before I put the old drum back in as a test.

blackcat4866
09-01-2012, 03:24 AM
I can't imagine the developing filter making much of a difference for that short a time. Eventually you would have gotten a dirty laser slit glass ... hey, that's something to check. If you've still got the old primary, I'd install it in the new drum assembly just to see if it's any different. =^..^=

Kidaver
09-01-2012, 03:30 AM
We didn't do that bug in class but that's good info to know. Tho we did do the bug were if you plug the laser ribbon cable in backwards you will not get any error code but the machine will just print out blank pages all day long.

blackcat4866
09-01-2012, 03:34 AM
We didn't do that bug in class but that's good info to know. Tho we did do the bug were if you plug the laser ribbon cable in backwards you will not get any error code but the machine will just print out blank pages all day long.

Funny! Yeah all the contacts are on the opposite side. =^..^=

Darren King
09-01-2012, 04:01 AM
I replaced drum and developer at normal interval, immediately afterward problem occurred.


Front side of image has thousands of random white dots on fill of image. Mostly white sheets like counter printout look fine, a gradation chart is terrible. Only a handful of dots on rear side of image (portrait)

I put old drum back on and spots still there.

I will return with Dev unit and more developer.

Any thoughts?

Thanks in advance!

I have seen dirty ozone filters cause some strange image problems.
Darren

JR2ALTA
09-01-2012, 04:10 AM
Thanks gang,

This is definitely one I will check back in on. I'm not sure about the laser, I print a dozen or so sky shots, the amount of "constellation" spots will vary, but it's always bad...just sometimes worse.

The damned thing is that I have bad luck with getting background after these PMs, this time i saw a pure white background, did a dance then saw this...

BTW the dust catch I mentioned was the one under the transfer roller. Everything is clean and spiffy as far as paper path and laser glass goes.

Mr Spock
09-01-2012, 03:01 PM
On the c451 and up series they tracked this down to the mfp pwb. This is where image processing is done and something goes wrong on pwb causing it. It maybe the same thing. Hopefully not. I have a pwb that does not take a firmware update and use it for testing when I come across this issue. 90% of the time it is the pwb, especially if the defect is on the drum.

BDT Tech
07-25-2013, 03:34 PM
I have quite a few of these in the field. You need to replace the DV unit. If you let it go it will later have occassional sheets that have a strip of grit going across from the paper feed direction and then it will have what looks like black scales. It starts out as an occassional thing and gets more frequent. The first symptom is stars on the sky shot though. I have never had this issue after replacing the DV unit. It usually starts after replacing the DV powder. I am experimenting with not vacuuming out the DV unit when I replace the powder to see if that is the cause. I have had this at least a dozen or so times.

Hansoon
07-25-2013, 06:17 PM
I don't get it. Is this not basically almost the same Image Unit as the previous series? With those there where not such problems I believe.

Hans

BDT Tech
07-25-2013, 06:39 PM
I wish I knew the why. Maybe I'd make more money. I just know what has worked for me.

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