Diagnose a NeXT 400dpi Laser Printer

Started by bobo68, February 24, 2016, 08:51:35 pm

Previous topic - Next topic


Quote from: "barcher174"I'm curious about this diagnostic unit you connected. Can you share more details?

Hi Brain,

it's mainly cabling, a PCB and some jumpers so I could connect various signals to either supply or GND. Nothing fancy. I'll post a picture tonight.

When I was in the middle of diagnosing the unresponsive printer, I was contemplating to make a real diagnostic unit out of it, just for the heck of it - but then the thermo switch revealed itself before...



Quote from: "Rob Blessin Black Hole"
Here is the Laser Printer doc in full http://www.nextcomputers.org/NeXTfiles/Docs/Hardware/  
Thank you !

Actually I really have to thank you for providing all these scans and other files!

Some nights, I went to sleep with a printout of the service manual in hand. And it was an unbound printout, so in the morning there was a sorting job to do :)



Quote from: "bobo68"I had some success. Found a utility named printer preferences ("PP") on a NeXT PD-CD. It show the status of the printer and allows to make some settings.

After I fed the printer with fresh paper it started to print but would not be able to pull the paper through (exept for one time).

Here is an interesting maintenance video for the printer: https://dl.dropboxusercontent.com/u/1429222/Videos/nextprinter.mov (can somebody copy it to the file area?).


where can I find the  utility named printer preferences ("PP"), please help

Rob Blessin Black Hole

Quote from: "rockus"These are the photos of the thermo switch and my mounting. It's intended as preliminary. But as things go, it'll probably stay that way...

Ideally, from a historian's point of view, I would find out how to get the original mounting out of the point-welded assembly so I can re-use it...

Hello NeXT Community:  I have gone through 2 stacks of NeXT laser printers 20 total.   My findings are most of them will initially power up , if you can position your self to look in through the crack by the exit tray , you should also see an orange glow .

I noticed if that does not happen than logging in and using print manager , opening the cue and choosing test print will just sit at idle.  In looking at this post (thanks Oliver) , is this a symptom of the thermo switch being toast?

If it does glow and you log in and run a test print , it should glow again my guess is it is getting things up to temperature to print so then you hear the intake drive motor start up.

Then another issue crops up Paper jams: A few things can cause this:
1) Paper
Thick laser printer paper is recommended also microwaving a small stack for 15 to 20 seconds draws the moisture out
2) Intake roller
Chances are the intake roller has shrunk overtime and I've had limited success cleaning the intake roller and 5 smaller rollers and 1 longer roller
with Rubber Rejuevenator , in the example they use acetone.


Still doesn't work I did this for the first time ,lol after all these years , replaced the feeder roller , so there are 3 deck lid screws and then seven internal screws but the catch is the ones that hold the assembly to the case are cheap and easily strip if off center , it seems like 1 in 4 is torqued way down  so care ful right sized philip's screw driver is important .
taking the assembly out tight tolerances but she comes out and clips to remove old roller and put in new one .... took me twenty minutes.
and it worked with a catch ,

3)  the bloody expeller year on the printer is worn out ...

so I switch plans  surely I can just swap out this know good working new intake roller into a printer   that lights up and tries to pull paper in.

Thought I had one #20 finally  but started to strip the screw on the surface mount and I am being really careful. I need a reverse bit to back it out.  

I had success with 4 printers in the last few month's  but this whole batch has me rethinking everything, They can't all be bad as a few of these are in nice cosmetic condition and I suspect replacing the thermo switch and intake roller should have me back up and running.

The expeller gear replacement looks complicated  at any rate , I'm recycling a bunch of them that I think look ridden hard and put home wet, extracting the logo's , logic and emulator boards which we can use to make non adb sound boxes and will save few spare parts..... usually if your printer latches are broken and the deck lid pops up tis a sign of previous anger with the paper jam problem. I'm being patient so Matt hopefully i'll have a working one for you today.   I'm evaluating is it worth it for me to try and repair these I have a few listed for sale as props on eBay for $59.95 , if you are serious about repairing one , I will sell you one of the nicer ones it includes trays and cable and I also have cartridges for cheap $20 and I will tell you what I think is probably wrong with it , heck buy 2 for $100 for spare parts, new intake roller $15 , I may even order a couple thermo switches and take a shot at repairing a few ,

As I've used the same mono turbo system to test  all of these, so I'm going to make a fresh DD of the SD card  to make sure there is nothing corrupt in the printer spool files or  cache .

It would be nice to have software diagnostic that may point to the failed component , Brian any thoughts?

wish me luck I just need one working one to fill the order onto printer 21.

Rob Blessin President computerpowwow ebay  sales@blackholeinc.com http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community  since 2/9/93

Rob Blessin Black Hole

in addition to above blast , I also found this which should prove useful in Troubleshooting .

   Printer Troubleshooting
      If you have trouble with your printer, the most common causes are:

      Defining the wrong baud rate between your NeXT computer and the printer (see "Attaching a Printer" earlier in this chapter).
      Using a Macintosh serial cable. These cables are incompatible with 68040-based NeXT computers, and are usually incompatible with 68030-based NeXT computers.
      Using a serial cable designed for a 68030-based NeXT computer on a 68040-based NeXT computer. They're incompatible.

   For help in diagnosing printer problems, the file /usr/adm/lpd-errs might contain some helpful information. This file contains a log of any errors that occur during the printing process.

You can get further help in diagnosing printer problems by downloading the program ehandler.ps, located in /usr/lib/transcript (this is for PostScript printers only). This program makes the printer print a page listing any errors after each job is printed.

To download ehandler.ps, enter the following in a shell window:

lpr -Pprintername ehandler.ps

   Once downloaded, ehandler.ps continues to follow each failed job with an error sheet until the printer is reset or turned off.
Rob Blessin President computerpowwow ebay  sales@blackholeinc.com http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community  since 2/9/93