Xerox 5021 copier, 1996 vintage with "U4" error code. Comes on, one fan runs but nothing lighting up on the control panel except that error code and "see user guide". (naturally for this particular code the user guide says "call for service" :rolleyes: ) Press "stop" and something makes a noise..otherwise pretty much dead.
One of these deals where it's a fairly low copy total machine but it sat around not being used much...maybe a few copies a month..and one day my parents turned it on and get this error code...working perfect before that.
I just now Googled Xerox and U4 and came up with the following-
U4-1: Fuser took too long to warm up
U4-3: Fuser temperature too high
U4-6: Web count expired.
U4-7: Open fuser thermistor
Mine has just 'U4' but wonder what 'web count' is ?
U4 is usually a fuser problem. Is it a U4-something? Like U4-2 might be fuser over temp.
Heck you might get to replace a fuser triac or something.
Some Zerox U4 discussion I found:
I see your edit includes these ideas. Maybe you can get in some good hunting with your trusty meter.
Yes, so far the possiblities are looking like -
1. Overheat fuse of fuser blown
2. Heat rod died
3. Fuser triac blown
Any ideas what a heat rod or fuser triac look like and where they would be found in the machine ?
Sometimes the internet gives you exactly what you want almost instantly. Thus far, I cannot find a picture of a fuser triac and its place in the copier. This is a triac though.
The thermister in your machine something like this.
Found this page of info on your machine. May be handy.
I finally figured out my error code is U4-1 (the secret is to press zero to see the subcode number)
With this knowledge I was able to clear the code and now the copier is fully "alive" again. But it eternally says "not ready" and I note the heat lamp for the fuser never lights up or gets hot at all. Sooo, either need new lamp (same as 'heat rod' I presume) or the thermal fuse for the lamp is blown. Looked all over for any hints of fuses but can't find any.
I guess next step is to check resistance in that lamp or check for voltage at it's connectors to see if lamp kaput or not.
Two possibilities on the lamp not lighting.
1. the lamp is blown(duh) 2. the thermal fuse is open.(both things you have mentioned) Heat lamps and thermal fuses can die from old age due to the many heating and cooling cycles. Also a bad thermistor which senses the fuser temp could be bad allowing the fuser to overheat thus blowing the thermal fuse. It's fairly easy to work on and replace those items. I doubt the triac or ssr is bad. Rarely see them go bad in any brand.
First thing is to check the lamp continuity. You can see the connectors coming off the lamp wires.
Those connectors are a pia but if you fiddle gently with them they'll come apart. if the lamps good next check the thermal fuse. To get to it you need to remove the black plastic assmebly on the top of the fuser section. Remove thel ong black screw on each end and it will lift off along with what looks like a white scroll. I don't think there's any other covers to remove. Look for a small rectangular block with heavy wires coming out on each end. Pull one wire and do a continuity
check on it. If thats not it let me know and I'll look into it farther.
p.s. I guess by your post you have found the fuser section but just in case, when you open the the machine it is in the bottom half on the left.
My Xerox had a fuser failure, the fuser is a HOT roller that the paper runs through to fix the toner to the paper. I my case the driver gears were nylon material that got brittle from use and shattered. I was able buy the gears and she runs fine now. The seller of the gears said it was a common problem with the XD155 I have. Since the machine is now six years old I also got a spare set. They don't make parts for very long for office products.
my wheels don't slow me down
Mike P, the fuser is in the housing that the hot lamp runs thru right ? Seems to be called "web housing" though..
The webb housing is the part directly over the fuser that contains the white scroll that comes out with the two long screws That whit scroll is the cleaning webb . "Fuser section" is a general term for the whole area below that. Yes it contains the heat roller with the lamp running through it. When you open the machine like a clamshell it is the area in the bottom half on the left. You'll see the ends of the quartz halogen lamp about as big around as a pencil and the leads coming off it. Along with the blown lamp or thermal fuse possibilty I've also seen the lamp connectors get fried and cause that fault.
Wish I lived closer, I'd pop in and give you a free repair
Just an update that I finally got around to checking the situation and it was the fuser heat lamp that was burned out...got 115VAC at the lamp terminals, but no heat or light from the lamp itself and infinite resistance on the lamp terminals when disconnected.
Well you didn't need Evan after all.
Now if my bid of $1.25 on this replacment lamp will just hold, I'll be set ! The normal price is $80
If I never fix another Xerox copier I will die happy.
Don, when you get the lamp wipe it down with alcohol. Any fingerprints on the quartz will oxidize and form a hot spot that will dramatically shorten the life of the lamp.
As for replacement parts prices, Xerox commonly makes around 1000 percent markup on parts.
Evan, thanks...I hadn't thought of that...maybe that's why the eBay seller made a point of stating "never touched by human hands" ? [img]smile.gif[/img]
Do these come in a pretty sturdy box ? Just seems like something that could get easily broke in two during shipping.
Is the Xerox 5021 a decent machine ? I got it for free, so if it's a POS don't worry about upsetting me with bad news
The 5020 series have a couple of problem areas to watch out for. The photoreceptor (the part that actually captures the image) is a mylar belt coated with photo sensitive material. It is easily contaminated both by slight outgassing from parts of the machine and from external sources. This shows up as a faded area on every other copy when multiple copies are made. This cannot be fixed except by replacement of the print cartridge. This problem will vary in severity depending on firmware level, location of the machine, temperature, humidity and use. To help prevent this it is best to turn the machine off when not in use. Also, the print cartridge has a hard stop limit on the number of copies that can be made. IIRC it is 25,000 copies but I could be misremembering.
The second possible problem is that a lot of the early models had a faulty power supply. The filter capacitors didn't last. This power supply is buried deep in the base of the machine under the fuser unit and is a pig to change. If it goes a replacement, if available, will cost more than a new machine. Again, the best way to prolong life is to turn the machine off.
Don't depend on the optical system to produce accurately scaled copies. It uses cog belts throughout to move the optics and usually develops errors with time as the belts stretch.
The web that cleans and lubes the heat roll can be rewound if it runs out. This isn't easy but it can be done in a pinch. However, it shouldn't be rewound all the way as it won't fit on the supply roll since it won't be as tightly wound as a new one. Also, the web counter must be reset in diagnostics mode to make the machine think it has a new web. No, I don't remember the codes and I threw out all my manuals, sorry.
If the lamp is in its original box it should be fine.
I see you got your lamp. What Evan said about that machine is right on. I'm no big fan of Xerox but that model was actually fairly decent.
Good luck with it.
Evan said "If I never fix another Xerox copier I will die happy". You escaped the immense gravity
of the black hole of copier repair Congrats on that.
So who makes the better copier machines now days and of the group who makes the better sub $1000 copier machines?
Escaped, yes, eventually. I worked for them for 23 years. It was a good place to work at first in the 70s and 80s but in the 90s it all went to crap as the company jumped on the right sizing/down sizing bandwagon. When I quit (in good standing, no buyout) I was consistently carrying 1.5 to 2 workloads. I became tired of it and started my own computer store. I am still in business eight years later.
Update on the Xerox...finally got the fuser light in, installed it today and she's working !
Now the only problem is the 40 multi page feeder doesn't work properly. Put one page in and you have to help it get started, otherwise it slips and doesn't go thru. Put 5 pages in and helping it doesn't get the ball rolling as all 5 pages go too far and it slips.
Maybe the rubber on the little feed rollers has got too hard over time ? If so, any way to soften it up...alcohol maybe ??