DP-8035 U9 after major PM

**Vista David** · 01-29-2013

Hey guys,

Last Friday I did some work on a Panasonic DP-8035. I changed the drum, dcb, developer, fuser web, corona wires, toner waste container and feed rollers for tray 1 and 2. After changing the fuser web, drum, dcb, corona wires and developer I turned the machine on and performed a TDC adjustment. After the adjustment, the machine printed out a few documents that were in the queue and they looked great. I turned the machine off and removed the paper feed mechanisms for tray 1 and 2 and replaced the feed rollers. I re-installed the paper feed mechanisms and replaced the toner waste container in the back with a brand new empty container. I put the panel back on and turned the machine on to see that it has an error code U9 and it instructed me to close the left cover. I looked up the error code U9 and discovered that it was, in fact, an open left cover.

The only things that the service manual tells me are:

Left Cover is Open.
Left Cover Sensor is disconnected.
Left Cover Sensor is defective.

I have opened and closed the door multiple times, replaced the left cover sensor with a known working sensor, traced back the wires from the sensor to the DRV board and disconnected and reconnected the connector on the DRV board, along with turning the machine off and on multiple times and trying a different power source. I am now lost as to what to do and any help would be GREATLY appreciated!

**copiman** · 01-29-2013

U9 is for the cover on the left side below where the paper exits the machine. I'm saying this because my first thought when I read your post was the exit door. So I started thinking about the exit door and wondering what could have caused it. Opened the exit door on my machine and no U9. Then it hit me. Just thought I would throw it out there.

**Vista David** · 01-29-2013

Yeah, the door under the exit door is the one that I've been troubleshooting. There is a sensor on the left side that triggers when the door is open and that's the one that I have replaced and traced back to the DRV board. Thanks for the heads up though!

**doug94550** · 01-30-2013

From the heart, I am sooooo sorry. You see, the evil U9 bug and I have a history. I placed a couple of posts here about the same problem. Here's what I have got, and it ain't pretty.
I have serviced the product from it's launch and had never seen of or heard of a U9 problem.
Last year I had two at two different accounts about 6 months apart.
So you have the lower door sensor. From there you have a relatively short harness to the driver board.
If you go to F4-005, if I remember correctly, you can monitor the state of that sensor.
On my machines, all of the bits were set to 1 when most should have been a 0. That was my first hint.
I replaced the sensor, no go. Then out of a shop machine we installed a driver board. Nothing. Then I installed a new harness. Same, same. Thinking the harness was the cause we installed another driver board. This time a new one. And still the U9's.
Eventually we wound up talking with Panasonic Support. After many hours of talk over multiple days it went down this way.
On the driver are a whole lot of pico fuses. These are less than 1/4 the size of a grain of rice. We would need to take the board and fuse by fuse, figure out which one was blown. From there, we would need to pull the appropriate harness and find the defect causing the fault.
And of course, when you get it figured out, give us a call and let us know.
In order to run the board you will need a board mount, a lighted magnifying lens, and micro probes to hit the pico fuses.
We never did find out what was causing the problem and the machines were eventually replaced.
For me, both machines exhibited identical problems. Which is why when we saw the second and that we were walking down the same path we had already walked, we got it out of the field fast.
I have never seen this before and hopefully I will never see it again.
This is a REALLY, REALLY nasty bug and I wish you the very best of luck.
And in the words of tech support,
"Let me know what it is when you figure it out"

Doug

**mojorolla** · 01-30-2013

I have had this a few times and the DRV board is usually the cause. You can go into F4 and test the sensors individually. The same connector on the board controls the web solenoid and discharge lamp. If either of those are malfunctioning, it's the board.

Most likely a web solenoid wire got pinched between the fuser and frame. Make sure you inspect everything before you replace the board or you will hose the new one too.