Faded Problem with 4000 even with a new toner.

[woodss]

I have a 4000 printer that's been given to me its April 1998 of manufacture, however its seems to be running slow with printouts not working the full 17ppm like it should, and print quality has faded too, it came from a college and the college technician and a printer technician told me that the Engine Controller PCA has a voltage issue, I am posting this in this website for some other opinions.

I would like to save this 4000 from the scrap, I know sometimes you can save them but I would like to give this 4000 another chance of life, the page count is 97,000 copies, premature death in my book.

I have placed a newly manufactured toner cartridge from a known working printer "4050".

I would like to ask which part of the Engine Controller PCA that is responsible for providing the transferring ground from the drum in order to transfer the drum to the paper, and nothing was on the drum, if it was its very faded out.

Something must be driving the machine down, causing the voltage down, at first the printer's motor is going normal, then when printing it slows down and takes longer for the printer to pickup the paper as well, this is a real test with my troubleshooting skills.

Sometimes when turned on for a while the quality does become more dense but still faded, and it looks a capacitor could be shot but which one, with my father's eletronics knowledge spanning over 40 years should help me to troubleshoot the actual board.

It has evidence of something inside the machine that is driving the voltage down, because when you first turn it on the motor is at a normal speed as soon you send a job to the printer is slows the motor down, its a lot slower compared with my 4050, which is based on the exact same engine of printer minus the formatter, my theory is that a motor or even the fuser is driving the voltage down for the quality to be so faded,

Whats even more interesting that sometimes the full motor speed does occour with using tray 2 quite well, when you do a Font Page test it prints at full speed, but to do a configuration page it slows down the motor.

However when the scanner assembly's motor speeds up little more when using tray 1 slows the machine down and it looks like some kind of voltage drop there too and after doing that tray 2 still keeps the full speed but sometimes it loses the speed.

And as the machine is used the printout gradually becomes darker, but not enough for the printer to be used in general, by examing the printer more is getting me convinced there is a voltage problem somewhere in the printer.

So the fading of print quality isn't the only problem is with the slow down of the motors when a print job is executed it slows down, the paper exits the machine a lot slower than normal, I have compared this with my 4050 which is a fully working machine which was manufactured in 2nd of January 2001.

This might be a case of a voltage dropout caused by one of the parts of the printer, which parts can do this other than the Engine Controller PCA?

[MichaelTech]

Well! very insightful post! Ahem,,have you thouroughly cleaned this unit?
Not just wiping it out, mind you, but completely tearing down this unit and most likely you will have to replace:
1}Feed assy. RG5-2651
2}Registration assy. RG5-2652
3}P\U "D" rollers {4} RB1-8865
4}Feed\separation roller RF5-1885

Also: drop down the ECU and blow off any toner , check fuses, and contacts.
Dirty fans can cause odd behavior, and of course, the scanner may be on the way out too.
Take off the main gear assy, and look for any build-up on the gears. Clean.
Remove the transfer roller, and blow out the trough it sits in.Check the contacts and clean.
Check the paper transport assy. in the middle of the unit. It may have paper scraps in it, or maybe a staple, or who knows what crud gets in there!
I hope you have the ability to do these things, as it doesnt sound like you are a technician. But, good luck! {PartsNow has a few diagrams that will help}

[woodss]

I have checked the scanner unit and its very clean inside, i do have a hardware training video for the 4000 all i need to do is follow the video, there is a lot involved but I feel confident to under take those tasks with the disassembly I have to seporate the engine from the tray assembly these are two different assemblies, i did not know that till i watched the video.

I suspect that the ECU has issues with the high voltage, however I will try the things that you suggest, maybe a reseat of the cables would do a real good for it, if anything it could be a problem with a capacitor or even a resistor, on this board.

Could a power surge cause this?

I have done a half test and nothing was on the drum, yet there was a faded print out on the page, the printer is writing on the drum but the printer is not developing the image and transfering the image onto the paper like its suppose to do, the fuser gets hot so thats fine also there is no error message either, it sounds like a high voltage issue doesnt it? if so could it be a transformer or a flyback? because it would take up too 400 or more volts to do such a task, and since there is high voltage that must be supplied to the charging / transfer roller to develop and transfer the printout the printer is failing to do this.

Because any writing takes place in normal working conditions, the high voltage unit of the ECU applies 400 volts to the drum via the charging roller of the toner cartridge and when the laser beam strikes the drum once it converts the 400 volt area to 100 volts and toner is attracted to that area some how this unit is failing to apply this 400 volts to the drum.

Officially, I am a college student, not a technician yet, however studying to become one :) I'm part of a generation of new technicians, between the video, service manual and forums like this and practice and asking questions I will get there.