I destroyed a printer so you don't have to.

Started by spitfire, July 21, 2022, 03:32:50 PM

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While consulting the printer service manual, I noticed that the document appendix is truncated at page A-4 and some key pages are missing.

Does anyone know if there's the faintest chance to retrieve them?


For those (apparently, not many...) who are following this thread, I have recapped the main DC board.
Now the printer is giving some sign of life, but it's still unable to start a printing job.
PP still giving hardware failure message, the printer monitor is complaining there's no paper in the tray or that the printer cover is open, even if it's not.
I need to check the other boards...


So, I could finally get the first (and so far sole and last) page printed.
After recapping all the boards, the unit came back to life (still something weird going on, though...).
It's hooked to a Cube 030.
During the booting sequence, at the very end, just before the login prompt, the unit is powered up, the main motor spins for 1 second (making sometimes very clunky and scary noises, which is not a good sign...).
Once you are logged in, the printer takes some 2 minutes to warm up. At that point, I can send something to print, means the printer status is "ready", which means that the fuser is at the right temperature.
First issue: the default state of the printer is "paused", and it doesn't wake up unless I open the Print Manager and push the button "Continue". Shouldn't be like that, I assume there's still something wrong... (Note: if I boot from MO with NS 1.0, the default status of the printer is NOT paused, so it could be some software thing...)
Anyhow, after sending something to the printer, it takes some time before the job is ready.
Once it's ready, the printer tries to load the paper. If it fails (in my case, it's 100% of the cases), it throws the dreary "Paper jam" error (which is triggered when there's too much delay from the start of the print job and the moment the paper is reaching the exit sensor) and from there on it's impossible to recover the situation, I have to restart the whole machine. Every time. Which surely is not normal either...

Main issue: the pick up roller. Or, better, in my case the combination of pick up roller and paper tray.
I have to say I'm not sure my printer is indeed 100% in original conditions, as the previous owner mentioned some attempts he made for fixing the faulty paper feed section.
So it could be that the pick up roller is no longer original.
Anyhow, I dismantled it, the rubber roller is in fact a chunky plastic roller sheathed by some 3 mm thick rubber sleeve.
To my eyes and to the touch, I would say the rubber sleeve is still sufficiently grippy. Anyhow, I removed the sheath, cleaned carefully with slightly abrasive "magic eraser", then remounted rotated some 90 deg compared to original position.
Better, but still unable to load the paper.
My attention then moved to the paper tray, which in turn is not exactly in pristine condition.
I could see that there's a pad in the front of the tray that has been replaced by something grippy and not at the right level, but my understanding is that - on contrary - it should be as frictionless as possible.

So, bottom line, by playing with the pad and by manually pushing a sheet through, I could get - by sheer chance - at least one page printed.
Sufficient for having confirmation that the rest of the printer is somehow healthy, which is already something...

Anyhow, I would appreciate if someone could share pictures of the original roller and the front pad in the paper tray.


I could get more pages printed, the output quality is not bad, the pages are still a little dirty, but the more I print, the cleaner they get.

Anyhow, the major issue I still have is that the paper is getting jammed 98% of the times, I guess the pick up roller needs to be replaced.

I have seen that spare part RA1-3851-0000 is suggested, but the roller I have in my unit is definitely different, it has a plastic core and a rubber sheath, similar to the one appearing in the service manual. The shape of the cam also looks somehow different.
Is it confirmed that RA1-3851 is fully compatible?

Second point for which I would need some help: is there a pragmatic way to recover from paper jam error? So far the only way I could figure out is to reboot the main unit.

Thanks in advance for support!


So, eventually I managed to bring back to life my Laser Printer, it now works like a charm, without missing a beat.
The wiper blade in the cartridge is probably deteriorated, so there are still two thin horizontal lines in the printouts, but it's more than acceptable.
Concerning the pick up roller, I replaced the rubber sleeve (probably not original) with some ultra cheap silicone rubber bands.
They are extremely grippy, durable and temperature resistant.
Paper feeding works flawlessly, both from the cassette and from the manual feeder.

IMG_3744 Medium.pngIMG_3746 Medium.png 


Nothing new or particularly exciting, but - just in case - here's a short video showing the printer at work.


Simple question (or maybe): is there any possibility to print alternate pages (even/odd) in such a way to get a front / back print in two passes?

Is there any specific printing utility a little more flexible than the default one?

Thanks in advance for feedback

Rob Blessin Black Hole

Hello NeXT Community: I'm having one of those days in NeXT hardware repair that I needed to take a break from it all.

 The equipment is aging as am I , 

 The latest NeXT Laser printer , I had it working right ,with new intake roller , cleaned it up ,

then it started bunching up the paper , had not seen this one before , the new intake roller basically crumpled it up taking the whole sheet in,

it would work fine hand feeding single sheets and spitting them out the other side with nice prints.

So I removed the intake roller assembly ,I can do it in the dark now .

 I had fixed the issue of it also not recognizing the intake paper tray with paper in it,
as there is a spring that holds the tension that had come loose so it would not engage the contact for the paper and tray sensor located lower right on base of printer.

Setting the spring back into the slot so it had a return spring action to it resolved it. I also noticed some of the assemblies have different style springs .... 3 coils verse 4 coils

I swap in a new assembly their are 2 very small parts , aluminum non magnetic that make contact with a brass roller and this starts the process of creating static on the paper. https://www.nextcomputers.org/NeXTfiles/Docs/Hardware/NeXT_Laser_Printer_N2000/NeXT_Laser_Printer_Service.pdf figure 5 on feeder roller assembly instructions:

The Little part drops directly down into the gears, seriously the last screw holding it in bumped it into the void aaaaarg.

I disassemble the feeder apparatus once more and I can see the damn thing , shaking no go, needle nose nope' Oh it gets worse as it disappears under the next set of gears, enter my stupidity at this point.

So there is a part with nylon thread , I know not to mess with that ever, yep it came loose, I think the needle nose clipped it so now I'm screwed six ways to Sunday.

I'm thinking myself there is no way in hell 20+ NeXT laser printers, I have here all have burned out bulbs. As this one, the one I just screwed up actually lit up orange.

I'm going to try swapping the top assembly with the bulb that lights up into another printer by referring to the manual. Some where in chapter 6

It is now personal with this printer but it has screwed me on doing my other NeXT hardware projects for today which in turn creates a domino effect.

I'll work through the weekend in silence finally, getting stuff done for my customers as the hardware Cubes and Stations will be much easier.

I am multitasking as well  with several systems set up ,

 installing software images on sd's and my latest round of ZULU scsi cards have arrived.

UPDATE on the Printer:  Well 4 hours later and with help of a surrogate printer and the manual , I was able to check and recheck where all the screws and parts went and the order to reassemble successfully . Some good new she powers up and lights up and starts to take he paper in but it uniquely folds it upwards rather than send it through the processing assembly . Enough for today, my NeXT move is to try a completely different feeder assembly with it's own new intake roller and drop it in , I've got this if it still bunches up then my guess is gearing alignment or the orientation of the new intake printer roller and side pieces as they are oblong , I currently have all 3 aligned but maybe the 2 end pieces may need to be opposing the center piece stay tuned.  Try try again....now I'm comfortable with an almost complete tear down of the NeXT laser printer , so I learned something today ....

############### Comment section , to follow as the Black Hole Turns lol personal drama and dilemmas general bitching below #######
So first is my left hip is so painful; I can hardly get from my bed to the bathroom some days, I'm trying I like to work .
The frustration for me mainly is my left hip was so damaged by MRSA , it collapsed the femoral head which means , I'm walking working on a fractured hip with no way to support it as I've tried with a brace.
I've been to at least a dozen appointments, MRI's, XRays and told by 3 orthopedic Dr's with a lot of experience it is a no go from them. Meaning they have passed on doing my hip replacement surgery , even though it was cleared by a infectious disease Dr this week.

Anticipating a cluster f$#% , fortunately, I kept the best orthopedic Dr. in the state Dr. Hug , yep that is his real name in my hip pocket and the appointment for December 7 still stands.

 I am assured today by his nurse , he will be able to handle any potential complications should they arise with my hip and joint replacement surgery.

However , he probably won't be able to have time to do the surgery until late March because he is in high demand.

That is why I tried t find other Orthopedic Dr's that would have been able to do this in a matter of weeks, so it was disappointing. Now normally I would be prescribed pain killers and arthritis meds like Embrel to help with pain management. The pain killers apparently are out as my primary care Dr is hesitant to prescribe anything beyond naproxen, ibuprofen and Tylenol these days because of my sleep apnia /asthma and my arthritis Dr won't prescribe enbrel because my immune system has been hammered by MRSA and antibiotics. 

My walker arrived today which makes it easier to move around the house and get to the NeXT equipment as my most recent helper Tom is MIA . Tom suffers from aging and is recovering from eye surgery lol

I'm considering ordering a tiny Violin trophy from Temu lol .36 Cents to help restore my confidence and honor , I know I'm good at this stuff it is just one of those days. On a real positive note I have the house back to myself .  So no more constant interruptions from Crazy roommates in their bad relationship which ended last Friday with her basically breaking in here taking a sledge hammer to his bedroom door. Then ransacking the room while I was on the phone with 911 and I found the restraining order paper work which helped a lot. Lisa was uber pissed at Todd as he took another girl to Guns and Roses.

I'm not making any of this stuff up and man  bro is seriously motivated now,  moving his stuff out daily under the cover of darkness finally.
I feel for the people, Todd is moving in with as I don't know if they are aware that he has 3 junker cars, 2 work trucks, one not working and a big trailer. Also half a garage of tools and crap, hey I'll have my garage back and 2 additional rooms of stuff like 3 fish tanks, oh add a shed and my old van full of more of his hoarder crap and no more excuses about him / her not being able to pay rent or any bills.  He started this move in July by the way last time I received any rent as well but he promises to do work on the house in the future, we shall see ....  as for Crazy Lisa aka sledge hammer nelly, where about s unknown, I would not be surprised if she pop's out from behind a bush ambushing him lol she is a vet and sneaky.  I don't want to know, not my circus not my monkeys, I think she drove them crazy at the jail as she was released the next day and all records of the incident mysteriously vanished but I did here she was kicked out of the Catholic Charities Homeless shelter so probably at a motel 6 with tweakers until she figures out where Todd moved to lol. I'm off to the post office to mail small packages then back to work the evening on the NeXT printer and many other projects. Thank you I have that off my chest, it is therapeutic for me and for those of us burdened with working on our beloved vintage hardware in spite of the environment , peace out. Rob
Rob Blessin President computerpowwow ebay  [email protected] http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community  since 2/9/93


By chance, today my printer went on strike, too.
I was in a rush for printing something, the printer ran out of paper (for real), I tried to feed some paper on the fly, but then it just stopped working at all.
I restarted the printer a few times, to no avail.
Eventually, though, just as I was just about to start dismantling the damn thing all over again, it came out of strike.

As for the feeder, it's indeed the most delicate part of the printer, light bulb aside. In fact, it was factory aligned, so in principle never ever touch it.

By the way, it still wonders me the fact that I am writing these lines on a machine with 4096 times the memory and god-only-knows how much cpu power more than the 030 cube driving my printer and that still I get seriously disappointed if something built some 35 years ago doesn't work as factory new.
I would have liked to have aged as gracefully as the NeXTComputer and the  Laser Printer I play around with...

Take it easy, and all the best with your hip.

Rob Blessin Black Hole

Hello Paolo: I read back through your thread messages here and last night I disassembled and reassembled the feeder assembly and horrendous clicking noises on power up.  Like you experienced :)

It is frustrating because you can't open the printer or remove the lid and activate the lid sensor switch to see in and identify the source noise. My guess is the gears are not in synch and this is probably my fault ,

I'm about 30 hours in to diagnosing this thing, at least 6 tear downs and rebuilds all carefully and fortunately,
I have a stack of NeXT laser parts printers. 

I think the clicking noises after studying the manual probably has to do with the clutch alignment.

As my guess is the factory fine tuned the clutch assembly to match the gearing for each printer and it appears the made slight modifications to the assemblies in different revs.

I was hoping a simple feeder assembly swap would resolve the paper bunching issue.

As the original feeder assembly lacked spring or give so the paper simply hits a metal wall .

The replacement assembly does have spring however creates horrendous clicking noises and still bunches , the gears may differ just enough from earlier to later models.  Reminds me of the throw out bearing grinding in my 61 Karmann Ghia  because the 1650CC engine and transmission differ just enough to cause an issue in first gear.

The section above has the latching mechanism also  had a broken latch on one side (most likely previous owner printer jam deck slam), so I swapped it out by doing so I may have misaligned it just enough reassembling it ,

we are talking millimeters of tolerance here causing front end paper jam bunching, maybe I should try using a spark plug gap tool.

The new intake roller is working like a champ, it pulls in the full sheet of paper but it crumples it up never making past step1

 and I have actually had successful manual feed prints, so possibly the tray I'll try a new old stock intake tray.

 I don't even want to get started as to how annoying it is to have the 2 small aluminum parts drop into the gears , non magnetic so magnetised screw driver retrieval is out.
It is literally the last 2 screws when it happens it royally sucks

as does dropping 1 of 3  cover screws dropping into the damn gears, I've found setting a sheet of paper in their works most of the time to catch them.
 The tip says shake the printer upside down lol if this happens but murphies law the part you need to shake loose will fall further into the assembly 50% of the time and I have a fractured hip bone lol .

 I only wish I had a 24 hour cam on my efforts that I would be able to show to my customers waiting on their cubes and stations,
 but I'm trying to fix this printer for an interactive museum display in Washington DC.
 I had sent them a perfectly restored one but the damn ink cartridge exploded all inside the printer probably due to the difference in cargo hold pressure changes  or no pressure, just drop testing it by shipper.
I usually ship the ink cartridge for just this reason outside of the printer again murphies laws on this one.

I'm having one more go at this printer as we speak an if it doesn't go. It is being put on the bench for  few days as I have so many pending projects,

On a plus note my new red hot rod walker lol makes it easier for me to hobble around the house / shop and has a seat that works well for transporting cubes and monitors. Also it is nice to have peace and quiet restored to my living and working environment as my constantly arguing roommates are gone moved out finally! I may have to call 1 800 got junk because Todd has left a dumpster of stuff and I'm not sure he will finish up cleaning it out.

 It was so much easier when all of this NeXT equipment used to just work and I was physically healthy.

Thank you for the emotional support as you know working on the vintage hardware with problems IMHO causes emotional repairman PTSD trauma lol I know I am not alone.

The screw I was searching for an hour last night just fell out of the printer when I put the paper feeder tray in lol however it still makes noises and jams.

 I'll try one more time tonight,  like Thomas Alva Edison , by try 1001 the light bulb worked!

Paper Jam issue , I think it is the sensors and timing on the software combined with residual print jobs in the nextstep software usr/printer/spool swap disk pool , the amount of ram for theday and our patience causing us to just reboot the system as computer  things are so much faster now, doesnt mean they work any better though lol .
 I'm going with a small image on sd card as the old scsi drives noises are a form of torture lol
and using a dedicated NeXTstation for the print repair and server testing , keeps screwing up other NeXT systems out of the equation . 

In theory when clearing the paper jam works leave the lid open, remove the offending paper

Before closing the lid ,clear all print jobs from the print manager.app cue ,
 "clear the paper has jammed in your printer" pop up window (just press X in the corner to make it go away and then close the printer cover ,
With any luck you should hear the printer make a start up noise...
then try a new fresh test print from the printer manager app.
Open the cue in printmanager.app as well to see any still pending jobs as I say clear those out before setting the lid back down after clearing the jam.   I do have new old stock NeXT Laser Printer intake rollers for $15 and new old stock intake Trays for $20  and exit trays for $15, NeXT Logo Laser Printer Cables $20  for forum members.

If that fails to work yep power off and back up and it is OK to curse lol.

Don't slam the lid down on the printer as the plastic latching mechanism has become brittle with age when hearing the paper jam error , you can change the language of the voice of the printer jam  error as well lol the original siri. A broken NeXT laser printer latching mechanism opens a whole new can of worms lol  trust me , you may need a rubber room to decompress after working on repairing the NeXT laser printer or old malfunctioning computer hardware in general. Remember if you are frustrated take a break from it and try again another day.
Rob Blessin President computerpowwow ebay  [email protected] http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community  since 2/9/93


Hi guys,
So, apparently my printer too has decided to abandon me.
Not using it intensively (what for?), last week I printed a few pages, then switched everything off normally.
At the next restart, though, it got simply dead quiet. Not even the relay in the AC power brick gets triggered.
Now, in fact, if I disassemble the whole thing, reset it, put it back together, the relay closes and then immediately opens up again.
So, I would say there must be something that got busted and is now shorting.
At close visual inspection of each board and component, though, everything looks fine.
The lamp seems also to be OK.
Would you have any suggestion where to start from?

Rob Blessin Black Hole

Hello  Paolo: First to make sure it is a printer issue , if you have another NeXT see if the same thing happens on a NeXT with an original SCSI hard drive as I'm wondering if some of the Printer reset issues are related the ZULU or SCSI2SD images and their interface with NeXT software , printer drivers and timings etc......

Another troubleshooting option ,  I have plenty of NeXT Laser Printer OEM parts , I don't know if you still have the molds for NeXT 4000 Monitor feet but may be we can work a trade if you do.

I have a new old stock intake printer roller , Paolo, I admire your ingenuity on modifying the original roller but if you would like a factory replacement I have one fo $15 also I'm wondering if it may be your NeXT printer cable I have a lot of these and would like to see them put to good use Used $10, or new old stock $20.

We both both have been tearing these NeXT Laser printers down and rebuilding them or at least trying to with many others and it is kind of fun and a challenge.I just watched videos of someone restoring a 1958 Rolex watch lol the NeXT Laser Printer is much easier lol .

Check to make sure those 2 metal pieces one the right side of the feeder (Intake) roller assembly
are making contact as this starts the electrostatic process  https://www.nextcomputers.org/NeXTfiles/Docs/Hardware/NeXT_Laser_Printer_N2000/NeXT_Laser_Printer_Service.pdf pictured in figure 5

Along the left side of the front intake paper assembly, cover latching mechanism and cover sensor is a little ribbon connector make sure it is plugged into the PCB board, 

If you remove that assemble underneath it are 3 relay switches , these detect if there is a paper tray and the manual or automated feed all dependant on a few seconds of timings . If the roller doesn't feed the paper through it signals paper jam. So make sure they all click.

My issue with the printer is a horrendous clicking sound when it powers up and my guess is looking through the manual it refers to a clutch with a special factory tool , The NeXT / Canon factory Laser Printer Manual I scanned awhile back is proving to be gold https://www.nextcomputers.org/NeXTfiles/Docs/Hardware/NeXT_Laser_Printer_N2000/NeXT%20400%20DPI%20Laser%20Printer%20Complete_OCR.pdf

The Electrical System is thoroughly covered in Chapter 2 and The Mechanical in Chapter 3 step by step diagrams.

If it just was working as I say if you have a second NeXT see if it jump starts the printer ,

#### War Story ,I know when we had a full time NeXT laser printer for the Network at Alembic, we had a headless NeXTstation for the dedicated print server connected to the NeXT laser accessed over the network and usually when it went south , it was at the worst possible time. Faxing was big back then so I found on an inbound fax you could send it to PDF then edit the postscript with the Tailor post script editor app, which was earth shattering back then as I filled the forms out in Text and faxed them back blowing many peoples minds back then. 

##### I also know customers that day in day out printed up to 2000 page documents on a bank of NeXT Laser Printers, I would have to see it to believe it as a chorus of your paper is jammed inyour printer no doubt ensued at some point.

#####  We moved over to an HP 4MP Post script printer with a Jet Direct Card and that solved a lot of issues ,no more more having to reboot the print server , the server and the clients but it was neat when everything NeXT just worked.

I've been going through reading this entire document NeXT Laser factory service manual , this may help you....https://www.nextcomputers.org/NeXTfiles/Docs/Hardware/NeXT_Laser_Printer_N2000/NeXT%20400%20DPI%20Laser%20Printer%20Complete_OCR.pdf  page 2-28 and figure 2-41 talks about a protective system for over current that automatically shuts off the power supply to prevent damage if to much current flows through then it says to power it off .

I know there is that little NeXT Printer utility on one of the Peanuts CD's for powering the printer on and off from the OS, which I might try to see if it will simply reset the Laser Printer after a paper jam , in effect trick the printer into powering up and trying to intake the paper again without having to reboot. Also this is separate from the NeXT printer manager software.

 I also found the NeXT laser Printers have a fuse , located by removing the ozone filter and fan :)

I would check the power cable as well , I hope it is something simple ....  I'll try and help . I

For my printer issue... I'm also trying to see if there is something like a top dead center mark on the gears for alignment like in an engine .

 I think before disassembly next time I'll make a red alignent mark on the gears before removing the feeder assembly (intake roller) .

To try and trouble shoot this noisy sound and  it to see if I can get it to align  I may try rotating it 45 degrees at a time to see if the noise gets better or worse, dial it in as nothing in the manual points how to just referencing a "special tool"lol  .

 The frustrating part with this Laser Printer is I had everything working perfectly and the very last deck lid screw fell into the gears lol murphies laws.

I now set a simple sheet of paper inside the printer  so if the deck lid screw drops from the magnetic screw driver , the paper catches it and it doesn't disappear in the gears. At first I thought the noise I'm describing might have been a screw in the gears lol but no it is definitely gear alignment.

Stay tuned as I had another NeXT printer come in the original box and I'm hoping it will simply be an intake roller replacement.
It is cold here with about a foot of snow on the ground so I'll be working on more NeXT projects all week.

Hopefully my assistant Tom will be able to help as it makes it so much easier for me to keep pace with all of this holiday NeXT madness lol. Normally we have Black Friday shopping event, this year in the states a lot of the stores we're very empty so a lot of merchandise is piled high in the stores and amazing deals on electronics will probably happen.

The economic problem is prices for everything like food , utilities, rent, property value and mortgage interest rates, cost of health care and insurance and people with heavy credit card debt and interest, people  are leveraged and stressed  every where and many are priced out of holiday shopping....
 I've been lucky enough to remain in a frugal lifestyle, paid down my debt and miraculously covered the hospital expenses,  I also try and remain fair on my prices  for everyone , thank you all for your support and I hope all is well with your friends and family

I'll never get rich doing this NeXT stuff and don't need to be  as I'm happy doing it and who would hire a 60 year old vintage computer specialist with multiple health care issues. So it is a good thing I hired myself to continue carrying the NeXT torch  awhile back and against all odds have made it work.
#### End of rant jibberish lol
 Oh and my hobby is tracking the Powerball with statistics and code breaking , I have to put the good old NeXT's to work with Mathematica and Improv and when you hear someone some day in Fort Collins wins big, it has to be me lol, I'm trying to manifest a win , according to tic toc social media advice .....well that would be me, ha....

 It is funny CNN says we broke a record today of 9.8 Billion in sales for Black Friday, conspiracy theory of sponsors perhaps influencing the news but Tic Toc says something else and I honestly believe the folks showing video of empty Black Friday parking lots Walmart, Kohl's and Best Buys piled high with unsold merchandise from yesterday,

I know here in Fort Collins as it was 10 degrees and a foot of snow not much Black Friday shopping was going on lol Cyber Monday is easier. Link to my NeXT eBay store https://www.ebay.com/str/blackholeinccomputerpowwownext   , if you want to learn all about NeXT , I have an  Excellent  book / gift  Inside NeXT available here https://www.ebay.com/itm/285488380132  Happy holidays !
Rob Blessin President computerpowwow ebay  [email protected] http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community  since 2/9/93


Hi Rob,

Thanks for the very detailed reply to my generic inquiry, it's very kind of you, I appreciate it.

I spent the whole afternoon trying to figure out the root cause of this sudden death. To no avail.

Unfortunately, I don't have at hand my second NeXT system, which is temporarily stored some 12000 km away from where I live now. But I would rather have a second printer (which I don't), for narrowing down the defective section.

However, I have swapped motherboard with a spare and I have also tried to boot the system from a different OS and start up device. No effect.

There seems to be some negotiation taking place in the boot sequence, but the printer just doesn't wake up.

I have thoroughly inspected all the recently recapped boards and they do look fine to me. I also tried to desolder some recently replaced capacitor just to check if some super fast degradation occurred. They are still perfect.

So far the only fact I know is that the relay (which I have tested as OK) is not closing when the main unit is supposed to be sending the "wake up" signal.

I attached a logic analyzer to the interface, I could record some activity, but I am afraid attempting some reverse engineering is beyond my reach without knowing what is what in terms of pinout and expected values.

Assuming the signal is sent and received by the DC controller, could be there's a safety circuit preventing the system from starting. So, maybe connected to the heater, which I am very reluctant to dismantle, for the reasons you know very well.

To this regard, about the scanned Canon / NeXT manual: do you still have the original copy? The PDF is truncated halfway into the appendix, where the interface to the system should be described... without that section, it's like having just half of the treasure map.

As for the rubber rollers mould, I still have it, but I am afraid I am not in the position of committing to making a new run any time soon (all the necessary items are also stored far away).

Rob Blessin Black Hole

To this regard, about the scanned Canon / NeXT manual: do you still have the original copy? The PDF is truncated halfway into the appendix, where the interface to the system should be described... without that section, it's like having just half of the treasure map.

As for the rubber rollers mould, I still have it, but I am afraid I am not in the position of committing to making a new run any time soon (all the necessary items are also stored far away).

I'll take a look around for the manual as I did not notice the missing section before :) , if you have an idea of which boards it may be I have a couple parts printers here :) or send a photo I can send you the parts cheap :)
Rob Blessin President computerpowwow ebay  [email protected] http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community  since 2/9/93


I think I have narrowed down the issue to the DC power supply.
First off, I found out a capacitor which was totally out of spec, then a cracked solder joint.
Once both issues had been addressed, at the next restart the fan briefly spun before the safety relais cut the current off, clear signal that there's still something serious which is not OK.
By the manual, the safety board seems to be connected to the heating unit, but before moving to that (almost hopeless) part of the printer, I would like to understand if the DC power supply is OK or not.
What I see is that the AC unit is filtering and directly feeding line tension to the DC unit, which in turn should supply +24, +5 and -5 V DC. However it doesn't seem to be doing so when under tension.
What I don't understand so far from the documentation is whether this is intentional (i.e. the DC unit is switched on only if triggered by the logic board, in turn controlled by the external device via the interface board) or not (i.e. the logic board needs in the first place to be powered by the DC unit for operating the whole thing). Kind of chicken and egg problem which hopefully will be further addressed in the remaining part of the manual, assuming it will ever be available.
Else, it would be very helpful if someone could check with a tester on a working printer whether the DC unit is always live or not. Thanks.