Troubleshooting Lexmark 4069 Fusers – Part 1

In my previous post I wrote about Lexmark T-Series fusers in general. Now I’ll get more specific. In this post I’ll try to provide some, hopefully interesting, observances about individual model idiosyncrasies, challenges and opportunities.

Remember, I’m not trying to tell anybody how to troubleshoot. Nor am I claiming that all the information contained here is gospel. This is just some stuff I’ve noticed, experienced and talked with other techs about over the years. It’s information that’s worked for me. I hope it works for you.

At the outset I’d like to say that Lexmark fusers are ‘complicated simplicity’. I said in the last post that Lexmark hasn’t changed much of the basic design since the Optra S. That’s the ‘simplicity’. The ‘complicated’ enters the picture with the number of little variations within each model according the Type Number.

Let’s begin our fuser journey with the Lexmark T61x.   This is ‘engine number’ 4069. Specifically 4069-xxx. Included in this series are 13 different models: two T610s; two T612s: five T614s; two T616s; and two T23s. Each of these has two (2) 220v and two (2) 110v versions. That’s a grand total of 52.

Confused? Overwhelmed? I was too until I realized that the main thing to look at is the last three letter/number combination of the “Type Number’. For example; T610 = 4069-010 or T614nl = 4069-41l. So when referring to the fuser parts drawings you need to pay particular attention to those last three numbers. Here’s page one of the fuser parts from the manual. Note the highlighted portions in the ‘Description’.

Index    Part #           Units      Description
12-1        99A1977           1            Fuser Assembly w/115V 875W Lamp
12-1        99A1585            1            Fuser Assembly w/220V 875W Lamp
12-1        99A1969            1            Fuser Assembly w115V 550W Lamp
12-1        99A1661            1            Fuser Assembly w220V 550W Lamp
12-2        99A0725          1            Wiper Assembly, Wet
12-3        99A1603           1            Cover, Fuser Assembly with Thermistor,Thermal Fuse,
and LH & RH Fuser Lamp Contact Assemblies
12-4        99A0263          4             Screw, Contact Assembly PP
12-5        99A1631           1             Exit Roll Assembly
12-6        99A1520           1             Gear, Upper Redrive
12-7        99A0833          1             Detack Assembly
12-8        99A1521           1             Hot Roll, 010/212/41b/41e/41l/21n/01n/23v/23e
12-8        99A1549           1             Hot Roll, 414/616/61n
12-9        99A0159           2            Spacer, Back Up Roll 010/212/01n/21n/23v/23e
12-10     99A1621            2            Bearing, BUR
12-11     99A0173           1             Solenoid Assembly, Envelope Conditioner
12-12     99A0263           1             Screw, Solenoid Mounting PP
12-13     99A0263           1             Screw, Board Cover Mounting PP
12-14     99A0160           1             Backup Roll, 22 mm
12-14     99A0158           1             Backup Roll, CBM 28 mm 414/616/61n
12-15     99A1598           1             Shield, Fuser Board
12-16     99A0144           2            Retainer, Backup Roll Bearing
12-17     99A1553           1             Board Assembly, Fuser
12-17     99A1868           1             Board Assembly, Fuser 41b/41e/41l
12-18     99A1649           2             Screw, Fuser Mounting
12-19     99A1902           2             Standoff, Fuser Control Board
12-20     99A0919           1             Standoff, Fuser Control Board

Some of these parts appear to be interchangeable when compared visually. But trust me, they’re not; at least over time. Notice the different lamp wattages; one 550w and one 875w. That’s 325 watts difference. If you rebuild one of these fusers and swap the lamps it will be noticeable over time.

A 550w lamp in an 875w machine eventually causes excess, unused toner to accumulate on the hot roll resulting in a print quality issue that will probably cause you to replace the fuser earlier than it should have been. It may also result in Error Codes 920, 921, 922 or 925. The end user will get one of these codes, power off then on and possibly reset the error, only to get a different error code later on.  By they way, all 900 error codes are fatal. The printer is down until it resets or gets repaired.

An 875w lamp in a 550w machine will cause excessive paper curl. The amount of curl will also depend on the paper used. Most notable curl will be on thicker paper like cardstock. Labels will be a real messy problem. Labels that get peeled off the backing get stuck to the holl roll and collect toner. The hot roll is done. I’ve rarely been successful removing a label from the fuser once it’s cooked to the hot roll.

Which is a perfect segue to the hot roll. Notice the different part numbers. In a previous post one of my collegues talked about OEM versus 3rd party or generic parts. If you’ve re-built these fusers you know what I’m getting at. The Lexmark T61x has two different hot rolls. These rollers are constructed with materials to match the wattage of the lamp, print speed and media types of a specific machine(s). If you match the OEM part number exactly, the fuser will have the proper lifetime, and satisfy Lexmark’s conditions for parts and materials.

Many of the “one size fits all” vendors list one part number that can be used in all models with the same “engine” number like the one we’re discussing here, 4069. And those hot rolls will work. I’ve used them for years to keep the cost of re-building reasonable. I’ve also done my own unscientific research on these kinds of fuser parts. And while it may not be consistent and may not always affect the fuser life significantly, it does have an effect.

Another part to watch for with these fusers is the backup roll (lower pressure roller). The differences between the 22mm (99A0160) and the 28mm (99A0158) is a lot more obvious, however, than most of the other parts. It’s real hard to mistake one for the other. But I’ve done it, all the way to completing the re-build, only to remove the wedges and find that the hot roll doesn’t even touch the backup roll. Oops, try again. So pay attention. There is not only a difference in size, but a difference in weight. Now I try to make it a habit to take the old roller with me to get the new one. The weight will help determine whether you’ve chosen the right roller from the bin.

Believe it or not, nothing I’ve talked about so far has addressed the most significant design feature of the 4069 series. That feature would be the electrical plugs on the front of the fuser. This was Lexmark’s attempt at ‘modular’ construction. It didn’t last. With the next two ‘engine’ series, 4060-5xx/7xx (T63x) and 4061-xx0 (T64x), Lexmark went back to the tried and true Lexmark formula. With the 4062-xxx (T65x), Lexmark has, in my opinion, gotten to a workable modular fuser design.

The 4069 design has some real interesting ‘opportunities’ associated with these plugs. For instance, the screws that hold the fuser in place are captive. So when the fuser is removed the screws stay with the fuser. That is unless the forks that hold the screws captive get even slightly bent. So, if the tech isn’t examining the fuser as it comes out of the printer the screws could come loose. Or, if one gets a little over-zealous removing the screws he could end up taking the screw completely out of the forks, damaging the threads in the process. And they’re big hex-head slotted screws just to add yet another type of screwdriver techs need to have on hand for Lexmark printers.

Let’s not forget the plugs themselves. They don’t always align themselves properly with the installed receptacles. So when replacing the fuser in the printer you need to pay close attention. You have to ‘feel’ it into place. Make sure the screws line up with the holes and that the fuser sits flat on its bottom. Then you can’t just screw it in. That has led to bent pins and, believe it or not, a bent fuser frame. Start one screw then start the other. Go back and forth like that until both screws are fully installed. A colleague of mine, while in a hurry, didn’t follow this back-and-forth procedure and  bent a couple of the pins in one of the plugs. That’s one of those goof-ups you try to hide from your shop mates to avoid hearing about it for next decade or so.

We also had a real hard time replacing lost or damaged screws (Fuser Mounting Screw 99A1649). Market Point carries them and I did find another supplier in Salt Lake City that had a few they were willing to sell if we purchased additional parts as well. Everybody else said their techs had some but they weren’t for sale.

Of course the new electrical design required a new fuser cover, lamp contact assemblies, thermistor and thermal fuse. All encompassed in one part number, 99A1603. Make sure your vendor knows you expect to get all of those parts with that number. Other than Lexmark, I don’t have a vendor that carries that part as described in the manual. I can get covers, and was provided alternate, proprietary numbers for the thermistor and thermal fuse. But the lamp contact assemblies remain illusive. So when those have degraded past useful I send the fuser in as a core for a vendor re-furbished fuser.

Now for the electronic boards: there are two in the T61x series, 99A1553 and 99A1868. If you examine the parts list carefully and match board to model the rhyme and reason gets lost. This exercise usually leaves me dizzy. The bulb wattage makes sense: 550 watt bulb for the 20ppm models and the 875 watt for the 35ppm machine. No problem. But the boards aren’t arranged using the same logic. So, my suggestion (harping?) is to make sure you match that last 3 number/letter combination with the part number you need.

You might also notice that the T614n is listed twice with discrepancies for both models. The first is 4069-41e for which there is no bulb number listed. The other number, 4069-41n has no board number listed. I’ve figured it’s a typo and used the parts for the alternate fuser and haven’t experienced any insurmountable problems. So, 4069-41n bulb in the 4069-41e and the 41e board in the 41n.

Yup. Dizzy again.  Now, just to add to the confusion I’ve created so far…

Remember I said earlier that the T61x was part of ‘engine’ 4069. The second and final part of this series is the 4069-5xx/7xx (T62x). There are only 8 models in this series. I am currently gathering the information necessary to provide some insight into this series. My research so far has presented some very interesting insights and revelations. I may even need to revise some of the information provided in this post. If so, I’ll highlight it to bring it to your attention. Stay tuned!


Brian Ude is a certified printer technician with years of experience. Brian serves Western Office ( in Billings, Montana.  If you have a question for Brian regarding this topic or have any other printer repair related questions or topics you would like more information on, please post a comment on this blog or send an email to

One thought on “Troubleshooting Lexmark 4069 Fusers – Part 1

  1. Nice post. We haven’t seen the error codes problem. Wondering how common that is. What are some of the rest of you techs seeing out there? Would love to get some dialogue going on this! Thanks.


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