Repairing/Cleaning a dot matrix printer

[SiliconJon]

Anybody out there ever done this one? I've done little more than change toner & ribbons and clear jams when it comes to printers. I do know these print heads get very hot, so I'm letting it cool right now before I jump into it. And I also know the pins can get stuck, which is what I'm going to estimate as the problem.

It's an AP-5000 [Epson]

There are lines of missed print at the bottom of each pass, causing bottoms of letters to disappear and pictures to have horizontal white lines in them. It just got much worse a few prints ago. New ribbons do not correct.

Any advice before I jump head first into taking apart the head?

[dunbar]

Yes - don't take apart the head unless the manufacturer defines the procedure.

I'd use some light solvents, I'd definitely try Isopropyl Alcohol, needle grade (91%). I think WD-40 might be a problem for some heads.

Put a drop on the face where the pins are hitting the ribbon, use a swab to wipe solvent around. Wipe dry, repeat until solvent comes away clean when wiped.

After the solvent cleaning, ASAP, start printing. You know how to put the printer into self test mode?

[SiliconJon]

Self test draft

Press and hold alt and load/eject then power on

LQ test

Press and hold alt and line feed/form feed then power on

Actually got a hit on that one!

[SiliconJon]

That didn't work. Cleaned it up, and was it dirty. But I still have the line. Going to give it once more over. And the tests, I don't think they're working. Neither causes any printing. The ALT+LOAD causes it to forward feed one dot at a time, and the ALT+FEED does the same backwards. It's the wrong key combo, as looking at the printer I see it says "Micro Feed" for those key pressings.

Well, three cleanings, once getting it back on "wet" and running it dry right away, and the problem is still there. BUT, it's not as intense as it had just become, but is now back to where it was when I hooked it up (been in the closet for nearly two years).

Data format: RAW
Driver Name: Unidrv.dll
Data file: EPAP5000.GPD
Driver Version: 5.00
Environment: Windows NT x86 [2KPro]

To clarify: when reinstalling the heads, I ran it through a test page without the ribbon to dry the pins.

[zepper]

You can soak the tip (printing end) of the head in about 1/2" of nearly absolute alcohol (90+%) either denatured methanol or isopropyl. Do this and change alcohol until no more ink shows in the alcohol - swirl the head around occasionally while soaking.
. It took a while to get my old Mannesmann-Tally freed up sometimes. The ribbons are supposed to have enough lube in them to keep the pins freed up, but after cleaning you want to use a very small drop of penetrating oil and carefully clean off any excess.
. Then print w/o the ribbon to remove any more or the printing may look funny for a while.
. If the data cable that goes to the head has bare metal contacts on either end that you can get to, use some contact cleaner on them.
. Also check the ribbon guide(s) to make sure the ribbon is staying in front of the pins. And that they can move properly (some do move up and down to spread the wear on the ribbons).
Good luck.
.bh.

[SiliconJon]

Hmmm....seems that pulling a little tension on the end of the paper (post-print) stops the lines...It looks as if the ribbon guard is rubbing against the paper. In low res, it just takes of the ink. In mid & high res, the ink is so thick, it drags it across the paper.

Gonna have to get some duck tape...

Seems a piece is missing from it, one that holds the paper down as it leave the printer...DOH! But the cleaning did work for the most part, as it was much more severe. Thx for the nfo up Dunbar & Zepper!

Oh, anybody now how else I may be able to put this thing into self-test?

[zepper]

Most Epson DM prtrs go into self test mode (barber pole printout) by holding down one of the buttons while you turn the power on - usually the line feed or page feed. Be sure you've got continuous paper in there.
. There is a paper thickness lever in there somewhere that might help with that dragging problem.
.bh.