[Error Code] L4-31 after firmware update on MX-4501N

[AnthonyH]

I'm working on a customer's copier that has a constant L4-31 that showed immediately after the copier was updated from firmware 2.08 to 2.10. I have swapped out all 3 fans related to the error, replaced PCU with another from a 4501 of same year (ser# 65037052) and have tried version 2.09, 2.10, 2.11 firmware. All fans turn on normally and the L4-31 comes up after about 10 seconds. We have no record of the main drive ever being changed on this copier and it does have the extra toner fan over the black hopper. connectors and pins on the board all seem okay, too. Nothing was done to copier other than updating the firmware.

So, if anyone has any other ideas, I'd love to hear them. And if anyone has a copy of the old 2.08 firmware they could link up, that would be great as well. Sharp has not been able to locate it anywhere.

Thanks.

[OMD-227]

Check that the harness from the main drive unit, plugging into the PCU board has the grey loop of one wire and that no pins are bent. Its on CN7 or CN9 from memory.

If your machine was made before january 2008, and you dont have the extra cooling fans fitted (other than the standard one above the primary belt unit), and the main drive has been replaced with the new version, you'll have a grey wire loop on the harness plug. This must be cut off, as it is the wiring to communicate with the new fan mods. The L4-31 appears when the harness/main drive is updated, but the fans have not been updated.

If your harness is the old style (no grey loop on the PCU plug), and you have fitted extra fans (mods per bulletins), then you need the new main drive unit or harness for this to work.

The fans rotate because they have power, but the return signal is missing because of either wrong harness or bent PCU board pin.

P.S. This has nothing to do with firmware versions. Make sure you're running the latest at all times.

[DAR]

Check the HDD cooling fan.

[OMD-227]

The code is for a failure of one of the paper exit cooling fans (on the delivery unit).
When you run sim 6 for a fan test (POFM - paper output fan motor) the fans will rotate as normal. In normal user mode, the code appears as there is no return signal (harness issue I've mentioned above).
There is a chance you could have an actual fan failure. These delivery unit fans were updated on the Pastel1's & C-Jupiter1's a few years back. If one of the delivery unit fans is not rotating at all, then thats your problem.
However, I've never yet had a delivery fan fail on a C-Jupiter. It's always the MX2300/2700 Pastel1's that go (early release models).

[AnthonyH]

Thanks for the replies, guys. All of the fans check out okay and were swapped out with working fans from another unit, so I believe it's an incompatibility within the harness that isn't correctly dealing with the fan lock signals. Sharp updated the PCU firmware for the new style toner radiate fans after firmware version 208 (E00) and I'm guessing that the main drive or harness was replaced on this copier at some point, producing an incompatibility. This is a pre-2007 machine, so it's not possible to upgrade to the dual toner radiate fans -- according to the Sharp bulletin.

Wazza, I looked on the harness for a loop, but couldn't find one. Was the loop right at the connector on the PCU, or was it located further up the wiring? I think the loop, or lack thereof, may be responsible for the issue.

Thanks again.

[OMD-227]

The grey loop is on the plug at the PCU board. There is only one plug/harness going to the PCU board from the main drive unit. If the plug going into the PCU doesnt have the grey loop on it, then you have the old/original type main drive unit installed.

In your first post, you say that there is an extra toner fan installed. Are you sure about that? You can upgrade an old machine to have the additional fans installed, its just that there is alot of work involved & alot of parts to replace/upgrade in the process. It definitely can be done.

It comes down to this......

If you have the newer main drive unit installed with old firmware, the machine will be OK.
If you have the newer main drive unit installed with new firmware, the machine will be OK.
If you have the newer main drive unit installed with any firmware, no extra toner fans, you'll need to cut the loop.
If you have the newer main drive unit installed with any firmware, with extra toner fans installed, you'll need the loop.
If you have the older main drive unit installed with old firmware, the machine will be OK.
If you have the older main drive unit installed with new firmware, the machine will be OK.
If you have the older main drive unit installed with any firmware, no extra toner fans, the machine will be OK.
If you have the older main drive unit installed with extra toner fans installed, you'll need to upgrade the main drive unit (loop on harness).

Double check you have the extra toner fans installed (not just the standard one above the cleaning assembly of the primary belt). If you have a pre-january 2008 machine, with an old main drive unit (no loop) and the extra fans installed, you'll have errors from the very first startup. If you have a pre-january 2008 machine with a new main drive unit and the extra fans installed, it will bootup OK. The key is having the loop on the PCU board plug. This communicates with the extra fans. This situation over-rides the actual error code definition in the book of 'paper output fan error' as these are not paper output fans.

[AnthonyH]

This machine has the single fan located above the cleaning ass'y. I'm not sure if these came from the factory this way in 2006 or not. It does not have the dual fan upgrade of the more recent models. I will check a newer model with the dual fans and see if I can find the loop.

We learned that this same problem happened in 2008 after updating to the then-new E22 (208) firmware from the E00 (209). The firmware was flashed back to E00 and the copier operated fine until after this recent update attempt. I'd like to find the E00 firmware just to get the copier up and running again while we figure out how to make it work with the newest firmware. The loop is hopefully the key to whole thing, though.

Thanks.

[OMD-227]

OK, now we're getting somewhere.....

If you only have a single fan above the transfer belt cleaning unit, then you dont have any fan mods done. Therefore, the plug on the PCU board, coming from the main drive unit should NOT have the loop on it. The loop is only for the machines WITH the fan mod updates.

Therefore, you'd have the original main drive unit installed. This is OK, as you dont have the fan updates. That being said, you can run any firmware you like. You dont need, or shouldn't be going back to 2.08 anyway. The update revision list is too long, with alot of fixes included in 2.09, 2.09n, 2.10, 2.11 & 2.11a.

Double check the plug on the PCU board (no bent pins, no wire loop installed). The more I read this, the more it sounds like either an actual fan or PCU board issue. Also check the fuses on the DC board, F201 through to F205.

[AnthonyH]

I found the loop tucked into the harness on CN12. Looked like somebody put some effort into tucking it in the harness -- odd. Was greeted with an L8-20 after cutting the loop, which was cleared by swapping Boot/Prog roms with a pair from another copier. The copier is now running the most current firmware for the first time in 4 years or so. Thanks again for the help.

[OMD-227]

I honestly think you found the wrong loop, because its on the only plug coming from the main drive unit to the PCU board. I dont have a PCU board on me right now, but I'm sure its CN7 or CN9 from memory.
Its a long loop of 6-8cm long, and its not tucked into anything, and you dont get L8-20 either if you cut the loop off.
The loop is only part of the updated main drive unit to communicate with the extra toner radiate fans. As your machine was made early, you dont have the fan mods or the updated main drive unit. I think you've cut the wrong harness loop.

But.....

You say the machine is now working. Thats great! I was going to say that I've done some more research and found that the single fan above the transfer belt unit is actually on the same harness as the paper output fans (delivery unit), so I'm thinking that was the problem all along. Your original post said you replaced 3 fans related to this error, but which fans did you replace? The 2 delivery unit fans & which other?

Either way, you've hopefully sorted this out, even if it does sound like it was done differently than anything else I've seen or know of. Fingers crossed XX.

[tmaged]

Thought I'd update this thread since I had one yesterday. The fan over the black drum/dv unit wasn't turning. I pulled it out & cleaned it. I think it just had so much crap built up in the housing & on the blades it wouldn't turn on. It was fine & I reinstalled it.

[OMD-227]

Nice one!

I've always found it amusing that this particular code is related to the output fans on the delivery unit, but the majority of the problems are due to the fan above the transfer belt either not working or not detecting due to that harness upgrade.
Sometimes it actually is a faulty/non-rotating delivery unit fan, but because the harness is the same, it can be the other fan. No SM even mentions this, unless you dig deep into the circuit diagrams.