Repairing Lexmark and Xerox MFP printers

We have two colour multifunction laser printers (in different premises) from Xerox and Lexmark that both recently and coincidentally had serious issues.

Part One - The Lexmark:

The Lexmark is an X792 bought in 2013. About 2 weeks ago it suffered a major fault and the LCD touch display was blank and non-responsive (but still had some dim backlighting visible). After speaking with Lexmark UK support folks they confirmed the unit was officially now discontinued for support (as of 2023!) and they would not be able to send either a technician to look at it or for that matter supply any parts. Ditto the various indy laser and copier repair guys I called up; sorry can't now get parts from Lexmark + we wont fit 'third party' obtained parts either, so we're not even going to bother to come out. Great start, not!

Decided I was going to attempt a fix myself, so after much googling, firstly located the 855-page official service manual. Then following a series of power on/off resets for diagnostics, I was pretty sure it was either the main system board or the low voltage power supply that had died. Given that the top scanning unit / still shone light when you opened the lid, the display was dead/unresponsive and the printer couldn't be reached over the network, I took a gamble on it being the system board.

The system board on one of these looks like this. Bit bigger than an ordinary computer motherboard but with a ton more connectors of all shapes and sizes coming off it from all sides and in the middle of the board. It's not a very service friendly design to say the least. I also managed to locate a new / genuine board in the Netherlands from a company called Service Parts International. This was €465 before shipping and VAT. Some other places in the US wanted over $1100 for the board! So I decided to take a gamble on the board with SPI and to be fair they were excellent. Dispatched immediately and arrived 2 days later via UPS. All properly sealed with Lexmark tape and kosher labelling. First little win.

Decided whilst I was in there to fit the full complement of RAM to the board, so managed to find two 1GB sticks of PC2-5300 SODIMM RAM from that vintage on Amazon for £16.

Now it was finally time for "surgery". With service manual on laptop and static wrist-strap on, away I went. Once I had removed the various plastic and metal covers, hinged elements and plastic protectors from the back of the printer - the system board was revealed in all it gory glory! I took a deep breath and started taking photos of all the connectors on my phone, just in case I couldn't recall what went back in what connector. Some connectors and wire patterns (like for the toner units) were identical and needed I needed the felt marker swab from the original assembly to know what connecter they belonged to. Looks something like this with the fax modem card and hard drive removed.

Happily enough about 2 hours later (I was gingerly taking my time), it was all back together again. Then it was a case of following the strict re-start guidelines to re-initialise the printer following the system board replacement (so the active config, serial numbers, firmware etc. gets copied from another working element of the system (operator panel, scanner card etc).

Mindful I could brick the thing at the final hurdle, I nervously pressed buttons 3 & 6, whilst turning the printer back on. First sign of success was the splash screen. Yay. Then slowly but surely the thing fully booted and test prints were OK.

Success was sweet. Made sweeter by the fact I was told it was effectively irreparable.

Edited by Pheasant (Mon 28-Oct-24 12:53:11)

Part Two - The Xerox

The Xerox is a Work Centre 7556. Bit of a beast from early 2012 that we bought when we were doing lots of printing. It's been a pretty reliable beast over the years, and the hard drive failing a few years ago and some bulk-tray paper feeder issues have been its only faults. Until recently that is.

The main issue was a smeared grey band across all printing. Without a service contract in place (we gave up on the PagePack agreement many years ago), official service from Xerox UK can be eye watering. So it was the case - Xerox UK wanted £678 for a fixed price repair.

Decided that was a bit exterme, so again with DIY-copier repair hat on, some furious googling, located the Xerox service manual (this time 1436 pages!) and a very helpful forum called copytechnet.com.

Firstly I discovered that the waste toner bottle/cartridge was overflowing chock full - despite the machine saying it was 2/3 empty! So a new waste toner cartridge on order for £28. Then I tried cleaning the print head lenses on each of the drum units. That failed to fix the issue. So I suspected one or more of the drum units was faulty (despite having plenty of service life).

So I order a couple of replacement drum units (they are all identical) and when they arrived I set about replacing them. It was the yellow drum unit that was obviously at fault. There was a whole heap of brown toner that had ruined the drum right where that smear would have been passed. A new drum unit and problem resolved. I expect the overfull waste toner cartridge led to its premature demise. Lesson learnt for the future, don't trust the consumables counters, always check manually.

Well so I thought. After a couple of successive power-on restarts to clear the fault codes, the unit was printing test prints cleanly and beautifully, but it was setting itself to the dreaded "Non Customer Mode" and so wouldn't accept printing or copying. Drats

Now after working out how to get into CSE / diagnostics mode, I had cleared some errors, but two stubborn errors kept repeating after resetting the unit. Google to the rescue for 303.355.00: Power On Self-Test Failure Detected During the NVM Integrity Test; NVM Battery is Dead

With that I discovered that there is a little yellow battery called the NVM (non-volatile memory) battery -that sits on a DIMM module, like so. Like all batteries these fail after a while. This one lasted 12 years, so that's not too bad. Googled and found a replacement battery, here in the UK for £17 + Royal Mail.

Thankfully Xerox design their system board to be very easily removable; a couple of thumb screws and pull back a plastic lever and the system board slides out in its metal carrier. A much superior design over Lexmark.

With that I thought, yes it's all over and fingers crossed re-booted the unit again. It takes around 10-15 minutes for a full reboot on these things. Quite slow really. So cups of tea are a necessity! The system came back up and as expected it behaved like a semi-new printer again and the expected dialog wizard screens came up. Unfortunately it now wanted an activation code. Argggh. Call to Xerox UK Support again. Alas it wasn't too bad and it only took a few hours for them to issue me with a fresh activation code.

Sorted!!

I enjoyed reading that it was a good read. Nice socks by the way.

🤣 I just dropped the photo in as was. No cropping of striped footwear here 😎

Pheasant must be one of those who adds Easter eggs to presentation slides just to check if anyone is paying attention.
Who needs analytics anyway?

Edited by prlzx (Mon 28-Oct-24 20:02:15)

Love a good Easter egg! 🥚 🙈😂

I'm hoping this Xerox machine will now be fine for a few more years yet.

The last "insurance policy" I'm taking out against its ultimate demise, is a spare 160GB 2.5" hard drive. The original was replaced back in 2017, so lasted around 5 years. This one's been going ever since...

Found that CPC Farnell were stocking re-certifed Hitachi SATA3 2.5" drives that match the spec., for a bargain £13.95 + VAT & postage. So around £20 all in!

Now I've just got to do a drive image copy and hopefully my insurance policy can sit on the shelf until it's needed.

That's awesome that, and those printers are well worth keeping going. Thanks for taking the time to post that as it was a nice read. In a previous place I worked we had tons of Xerox Phasers (eventually ColorQube), when they worked they produced excellent results, however when they went wrong there was always the treat of the Xerox engineers coming on site and getting highly frustrated trying to take the printers apart.

Once had the joy of one engineer turn up and mention his supervisor was coming along to check up on him, fast forward 30 minutes both of them swearing at the printer in front of everyone trying to get it apart and making remarks about the people who must have designed it.

Shame they discontinued the solid ink printers in my opinion, but there we go.

You can say what you like but you can't beat printing stuff!

Cheers.

The £13.95 hard drive arrived from CPC Farnell. Upon opening, discovered they'd actually sent a brand-new 2.5" Seagate Barracuda 500 GB drive (manufacture date is stamped as 11 July 2023 on it). So clearly not the 'matching' type & model "re-certified" Hitachi 160GB drive as advertised...

Anyway so I looked into the detailed procedure for a hard drive swap. Turns out that any hard drive swap in a Xerox requires the machines firmware and software to be reloaded from USB stick using the 'Altboot' process. As part of this process, when a new hard drive is detected after re-boot the machine automatically formats and encrypts the drive. So you can't image it externally and just drop it in. One needs to go though the firmware 'update' rigmarole.

A couple of folks have swapped out the original mechanical drives for SSDs in these things, not so much for speed, but as a more reliable device that should (hopefully) outlast the spinning rust. As it happens I had a new/spare 500GB Evo 870 SSD on the shelf, so this afternoon I did some further surgery and now have the SSD running in there.

So now the original Hitachi mechanical drive is the 'on shelf' hard drive crash backup solution for when the new SSD eventually bites the dust. Hopefully a while!

...and I thought that Hitachi drive got swapped in 2017 - but I looked at the serial number 42E7JUEJ and according to Mr Google the first three letters are the date code, so "42E" is 4 = April, 2 = 2012 and E = 14th day. So 14 April 2012. I think!! Maybe they swapped it with a 5 year old drive....

I wonder when it was going to crash....maybe it would have gone for another 5 or 10 years!!! 🤣

Edit:
There is a Xerox sticker on the drive, with a Xerox part number and the loaded software version of the printer firmware which was released in the first half of 2012. So I think the actual age of the drive is correct. I think what must have happened is that Xerox UK would have had a spares stock of these drives that probably originated from when the printers first arrived onto the market in 2011/12. So that probably explains why it's a now 12 year old drive, but was first installed during a repair in 2017. So actually has 7 years of usage and not 12 years.

For curiosity I popped the old Hitachi drive onto a SATA to USB-C adapter and had a look at it thorough Crystal Disk Info. The operational hours look lower than what I'd expected @ 9450 powered-on hours. I guess the the drive had been put to sleep when the printer was idle, which makes more sense with a power on count of 13,292.

Crystal says the drive status is 'good' but looking at some of the SMART stats I'm not so certain. Glad to have replaced it before it died unexpectedly. 😎

Edited by Pheasant (Sat 02-Nov-24 20:12:07)