4505AC Color Deviation- Yellow Only

**mojorolla** · 01-13-2022

4505AC current firmware and all OEM toner and supplies.
Unit has extreme color deviation on yellow only. Unit fails 05-4719, and 05-4720 has a value of 2, indicating front side yellow issue. The yellow patches are not applied to the belt as almost nothing is being written to the front of the yellow drum. I also performed the color deviation bulletins but all fail when attempting 4719. I also swapped drum unit, removed cleaned and inspected laser unit. Tested LED and reg sensor in service mode. Issue persists. I am 95% it's the laser unit but wanted a second opinion before that amount of money is spent. And OF COURSE, it is a 4-hour round trip. Samples and examples are below.
Thank you

**tsbservice** · 01-13-2022

I'm speculating but any chance Y drum to developer sleeve gap front side is bigger than specified.

**Rusty.Harris** · 01-13-2022

Sure looks like a laser to me. Had a brand new out of the box 4515AC that had zero yellow. Sent the laser to
Hytech under warranty, they sent me a message a new one was on the way, this was was deemed "not repairable".

**Vincent128** · 01-13-2022

Something is defiantly not right.

Clean the toner replenish chute then block it off.
Move the Yellow dev unit somewhere else.

Make the problem follow a sub-assembly ..but its probably the yellow is way out of alignment on the laser.
Align mirror motor may be stuck..unstuck it.
Lift one corner of the laser unit a mm and see what it does.

Is this in a cold environment ?

Don't rule out the IQC shutter, it may be giving wonky readings and screwing with the align procedure.

**blackcat4866** · 01-14-2022

The badly misaligned yellow patches indicates to me that yes, it's the laser. I've changed four or five of these lasers. I've seen that bulletin, and I've never been able to fix it without the new laser.

Usually it's the black section that give line patterns crossfeed and possible CA40, CE40, CE41 error messages... do I have samples? Yes:

4505AC Sample1.JPG 4505AC Sample3.JPG

I've also seen "Call for Service CA22". Yellow lines crossfeed 0.2mm wide. Magenta voids crossfeed 0.2mm wide. Errors out during initialization, leaving yellow and magenta lines on the primary transfer belt. Re-occurs 4 days later at 8:00 am (eS4515AC). The manual will tell you that re-seating the imaging units can resolve this issue, and it does ... for a few days, until it returns.

Another reason you might see huge yellow voids is when the imaging unit front alignment post is snapped off. The drum ground spring wraps around this post, so without the post the spring gets deformed. This particular customer has broken everything else you could possibly break, but this was something new for me. We have a bunch of these at grocery store merchandising departments, and these customers have been particularly destructive. Samples? Yes:

yellow absent_drum ground1.jpg

=^..^=

**mojorolla** · 01-14-2022

My 5% reservation is the yellow dv unit, but I just can't figure the horizontal and vertical shift that dramatic.
I also went into 08-4864 (I think) and moved the yellow color registration from default of 30, low then high. There was no change at all. Environment is typical sales office, nothing extreme. Drum posts are present, spring and gap looked good.
Toshiba wants almost a grand for the unit, getting it from Hytech for about 350. Also is telling that the unit appeared on Toshibas ribbon index 3 times with 3 numbers, indicating retrofits.
I'm heading back out Monday and will post with results.
Thank you for your wisdom.

**BillyCarpenter** · 01-14-2022

Originally Posted by blackcat4866

The badly misaligned yellow patches indicates to me that yes, it's the laser. I've changed four or five of these lasers. I've seen that bulletin, and I've never been able to fix it without the new laser.

Usually it's the black section that give line patterns crossfeed and possible CA40, CE40, CE41 error messages... do I have samples? Yes:

4505AC Sample1.JPG 4505AC Sample3.JPG

I've also seen "Call for Service CA22". Yellow lines crossfeed 0.2mm wide. Magenta voids crossfeed 0.2mm wide. Errors out during initialization, leaving yellow and magenta lines on the primary transfer belt. Re-occurs 4 days later at 8:00 am (eS4515AC). The manual will tell you that re-seating the imaging units can resolve this issue, and it does ... for a few days, until it returns.

Another reason you might see huge yellow voids is when the imaging unit front alignment post is snapped off. The drum ground spring wraps around this post, so without the post the spring gets deformed. This particular customer has broken everything else you could possibly break, but this was something new for me. We have a bunch of these at grocery store merchandising departments, and these customers have been particularly destructive. Samples? Yes:

yellow absent_drum ground1.jpg

=^..^=

The hardest working man in the copier business. lol