MXC401 L4-12

[bdcrandall13]

Have replaced with new transfer belt, both primary and secondary with latest mods. I see suggestions to replace the fuser and even some to replace the Resist Sensor Unit. Any other ideas? I am heading out to see it in the morning. We just put the machine in the customer's office this morning and had worked like a champ the entire time we had it in our office.
Thanks in advance.

[bilyahn]

Secondary transfer seperation problem. Since you just replaced the belt I would start there.

Good luck.

Bil

Cause A change in the state of the separation sensor is
not detected in the specified time during separating
operation of the secondary transfer unit.
Secondary transfer unit separation mechanism
trouble
Secondary transfer unit separation motor trouble.
Secondary transfer unit separation sensor trouble.
Connection trouble of the connector and the
harness.
PCU PWB trouble.
Check & Remedy Check the operation of the secondary transfer unit
separation mechanism.
Replace the secondary transfer unit separation
motor.
Replace the secondary transfer unit separation
sensor.
Check connection of the connector and the
harness.

Replace the PCU PWB.

[wtroll]

Hello,
we have the same issue on MX-C310/380 in Europe.
the problem is caused by incorrect cleaning of the primary transfert cleaner blade.
Due to the toner contamination, the RESIST UN sensor may be unable to recognize the transfert belt giving irregular L4-12 code.
Change blade with new type (CCLEZ0216FC33).

Good luck!

[bdcrandall13]

Ok, we went to check the machine out this morning. They called yesterday and said the code had cleared and it was working again but had coded again this morning and would not clear. So, first thing we did is try to clear it. It wouldn't. We pulled out the 1st transfer belt and changed the cleaning blade to the newest version. I think it already had a new version in it but we changed it anyway. That didn't fix it. So we changed the entire belt to a new unit. That didn't work. We changed the secondary belt unit that didn't help. We changed the fuser and it didn't do anything either. The machine clicks once loudly after the FUM turns on, then clicks 4 times much quieter, but still noticeable, stops, then clicks 4 more times, then codes.
We called sharp and they referred us to TT-20213 which talks about the Resist sensor unit, the 1st transfer cleaning blade and the Fusing drive gear. I have tried to cleaning blade and we replaced the resist sensor unit. I doubt it it the fusing drive gear as it looks fine but will order it anyway. It says when checking the resist sensor unit make sure that it is opening and closing properly. My question is how does it open and close? When turning the gear or shaft by hand it does not turn the sensor cover. It appears the the entire unit is there after looking in the parts guide. Maybe there is something I am missing. I attached some pictures of the resist sensor unit and the secondary transfer unit. Give them a look and see if I am missing anything. Any ideas or thoughts are appreciated.
Here is the sensor cover unit. Again I don't understand what actually makes the grey cover move.IMAG0395.jpg

Secondary transfer unit. I don't quite get why the part below this is here. It is a flat peice with gear teeth on it. No idea...IMAG0396.jpgIMAG0397.jpg

[glewisme]

Check the firmware Sharp released a version to fix just this issue.

Complete Engine Firmware
Models MXC311, MXC401, DXC311, DXC401
Release Type Production Control ROM ID D04
Release Date October 2010 File Name CFRW_MAINsEFS_101122a.sfu
Versions
ICU MAIN
ICU BOOT
DESK
FINISHER
PCU
SCU
FAX
03.03.F1
01.02.F1
01.01.F0
01.03.F0
01.10.F0
01.02.F0
01.03.P2
Reason to change: (correction of error described below)
1. Changing the 2nd transfer separator control sequence could stop causing an L4

‐12 error.
Reason to change: (specification change)
2. A service mode to force toner onto the 1st transfer belt and to prevent the 1st transfer blade from being
reversed has been added to the engine software SW (Sim55‐1).
[Authorization/restriction settings]
0: Restricted (default)
1: Authorized
[Print volume settings]
0: 100 pages (default)

1: 500

[bdcrandall13]

Update:
Updated firmware to latest version. Changed fusing/delivery drive gear, secondary transfer seperation clutch, Registration sensor, entire right door including the secondary transfer belt again and the 2 seperation levers. Any other ideas? The machine still clicks once loudly when the machine is powered on, then clicks 4 times much quieter, pauses, the clicks 4 more times and codes.
Any input is appreciated.
Thanks

[jonr]

Re: MXC401 L4-12

The problem with your clicking noise is . on the back of the machine in the upper left side . small frame with clutch and three grears. i think. pull assm off. look very close at worm gear with diagonal teeth. you are missing one or two teeth on the worm gear. I have over 50 of these out and seen this more than once. I thinkl its was caused by fuser bearings that siezed or abnormal fuser drive bind. hope this hepls ya.

[Dougtech]

Re: MXC401 L4-12

jonr has good info.

Whenever I have this problem it has never been with TX roller or belt itself, it is always with the 2 cam arms (located in body of machine below the fuser a bit) that push to engage the 2nd transfer roller. check them out as something is causing them not to engage properly.
just my experience, good luck

[bdcrandall13]

Re: MXC401 L4-12

Gentlemen, we did find a resolution to this issue. It ended up being a Defective 1TUD_K sensor. All that work for a defective sensor. It was unable to see when the belt was in each position. A lot of lost time and money was put into this damn machine. But it works fine now!

[bdcrandall13]

Re: MXC401 L4-12

Oh yea, I forgot to mention that the sensor is the first thing that we replaced, but sharp's service manual had the wrong part number listed in the book and didn't have any changes noted anywhere. So the wrong sensor was replaced the first time...

[ZOOTECH]

Re: MXC401 L4-12 FYI

Oh yea, I forgot to mention that the sensor is the first thing that we replaced, but sharp's service manual had the wrong part number listed in the book and didn't have any changes noted anywhere. So the wrong sensor was replaced the first time...

We had the L4-12 error on a MX-B401 that would clear by pow down/up but then was pretty steady. It turned out that a simple cut of the shutter that covers/uncovers the Resist Pro-con sensor (item 28, section 31) allows it to work properly. The edge of the shutter (item 22, section 31) that covers/uncovers the sensor has a beveled edge that can be snipped off (about 1.5 to 2mm) and no more L4-12. This will work on the C-Frontier as well, but only the black tab is to be cut if you're getting this code.

[Ingersoll]

Re: MXC401 L4-12

Any pictures that show what you snipped off?

[ZOOTECH]

Re: MXC401 L4-12

Any pictures that show what you snipped off?

Sorry, no machines available at this time; the snipped edge is more like one mm than 1.5 - 2 mm.

[copiertec]

Re: MXC401 L4-12 FYI

We had the L4-12 error on a MX-B401 that would clear by pow down/up but then was pretty steady. It turned out that a simple cut of the shutter that covers/uncovers the Resist Pro-con sensor (item 28, section 31) allows it to work properly. The edge of the shutter (item 22, section 31) that covers/uncovers the sensor has a beveled edge that can be snipped off (about 1.5 to 2mm) and no more L4-12. This will work on the C-Frontier as well, but only the black tab is to be cut if you're getting this code.

I know this is an old post but I have a question about your modification. You have mentioned to cut the beveled edge, I see two beveled edges on the shutter. My question is do I make the cut from the front of the shutter (directly across it) or do I make the 1mm snip at the same angle as the bevels ( removing just 1mm from the bevels)?

[ZOOTECH]

Re: MXC401 L4-12 FYI

I know this is an old post but I have a question about your modification. You have mentioned to cut the beveled edge, I see two beveled edges on the shutter. My question is do I make the cut from the front of the shutter (directly across it) or do I make the 1mm snip at the same angle as the bevels ( removing just 1mm from the bevels)?

Cut from beveled edge to beveled edge - a little less than 1 mm. You'll be cutting back about 10 mm of the front (left) side of shutter. Hope that clarifies any questions you might have. What happens is the shutter does not retract enough to get a reading of the patch on the Primary.