Built like a tank and weighing as much as a small tank is one of the reasons that many HP printer owners prefer to have their printer repaired, instead of replacing it. They also tend to keep their old heavy printers running for a longer time. That's because they don't want to deal with dragging the old printer to the recycler and dragging the replacement back to the office. Best to delay such exercise as long as possible.
I acquired a lightly used HP Color LaserJet Pro MFP M477fnw printer form a customer that was closing their office. It weighs about 50 lbs (22.7kg). It took some effort carrying it up the stairs to my house.
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I'm currently refurbishing an HP Color LaserJet CP1518ni printer which weighs 40 lb (18.2 kg) which is giving me far too much exercise. I can see why offices don't like to upgrade and move heavy printers.
I couldn't find how much your Silentwriter LC-890 weighed.
No, that's a naive expectation. You don't need to keep an entire page in RAM to be able to generate a page *in* the computer.
You treat the page as a series of smaller regions (the top 1", the next 1", etc.) and define a clipping region into which you "draw" the page.
Then, ship that portion off to the printer.
Then, move the clipping region to the next region and repeat the process.
The printer can never know how long it will take you to send an entire page, so it has to be willing to accept a region's worth at a time... with indeterminate pauses between them.
The same process can happen in the printer (e.g., send a PDL representation to the printer and let it create a portion of the page at a time). If the printer can *internally* render faster than the marking engine, then it only needs enough of a buffer to keep ahead of the marking engine.
When printing text (using internal/downloaded font generation) and/or mixed text and limited graphics, this allows the printer to cheat on RAM requirements.
My Phasers were 1200dpi and none of them had more than 200MB of RAM (and they can't pause and restart the marking engine once it's begun)
So, whatever memory you have in your printer, by definition, is adequate for it to be able to print whatever it needs to print (subject to the caveats, below -- and above).
But the printer only has to store what it *thinks* it needs to print. E.g., if you can't resolve 16 bits of grayscale, then you don't need to hold 16 bits of greyscale per pel.
IIRC, color lasers print 4 different monochrome pages, in succession.
I'd assume that the reason to use plasticizer here would be for increased toughness.
Not necessarily. Plasticizers are rated by their volatility, which implies evaporation, versus extrusion. Nor do we know which plasticizer was used, if any.
Yeah, I've seen that too.
Sounds about right.
Hmm. It's a backup printer these days. Eventually, I'll de-accession it.
Well, my experience is different, for a simple reason.
I always bought printers intended for small businesses, for use in my home. These printers got enough traffic to stay healthy, but never wore out. I was buying reliability by spending up front.
Hmm. I don't think I've ever reached 75,000 pages on a printer, even with COVID related demand. I'll have to look.
Yeah. But my 5mp is still young at heart.
If I recall, I bought it in 1996, for about US $1000.
Lasers were ideal for my use case, as their ink did not dry out or degrade between uses.
This sounds about right, although where I've worked, company employees did perform service calls, like clearing jams that we couldn't clear ourselves.
Yeah I did the videos as well, ever having invaded the MFC-9840CDW's innards before. If I have to, I'll replace the scotch tape and gooey foam with wool felt.
By the way, the gooey foam is probably polyurethane, and the polyurethane is reverting to the urethane monomer from which it was made. There are urethanes that don't revert, but many are sensitive to oil and/or heat.
Wool felt is naturally immune, as is soft leather, attached with a suitable adhesive (which I have not yet studied, for lack of motive). It may be that the stickum that comes on adhesive-backed wool felt is already good enough.
Yes. Xylene can also be bought by the gallon at paint stores and the like. I have a gallon, used from time to time.
All I did was to abrade the outside of the rubber rollers with a big fiberglass scratch brush, and clean up after with isopropyl alcohol.
Yes.
I didn't bother with calculations. By the time I wanted or needed more memory in the MFC-9840CDW, the requisite DRAM was dirt cheap, so I just maxed it out, so I won't ever need to do that again. Not that it was difficult, once I figured the documentation out.
You can't trace the switcher schematic to see where the enable comes from? That seems a much simpler job. The last think I would suspect is the CPU.
I've not seen a repair shop that would even diagnose a unit for under $100. Unless you are talking about someone essentially doing this as a hobby a repair shop has to charge rates similar to auto repair, a plumber or whoever. None of this is cheap. What type of unit is worth $1,000 when it breaks? It may have cost $1,000 new, but I'm not going to spend a couple hundred dollars on a four year old computer. Computers become obsolete more than wear out. A small minority of users will waste their time trying to nurse old programs to run on a new machine or try to keep an old machine running when newer software won't run on it correctly. XP is a perfect example. I don't waste my time trying to run the same old OS on every computer I upgrade to. I just get on with my work.
So you suggest the typical user should get a bad unit, attend Devry training school for some months to learn how to repair it and then attempt to apply their new found knowledge to repairing the $10 clock they bought half a year ago?
BTW, only a complete idiot would make a special trip to the store to return anything. So the hour and the gallon of gas are bogus. As to your pollution, you are already a blight on the earth just like the rest of us. Do you apply the same consideration to pollution issues when you take a vacation or visit family out of town or even just keep your home warm or cool? A clock radio isn't going to tip the scales.
I can't believe you don't understand that issue. Literally by definition ham radio operators are a crowd that understand how their products work, at least for the most part. Clearly the design info is important to that market. Why would you not understand the difference with a clock radio?
Yeah, because up to the 70s people could and would repair such gear as it was relatively expensive. Now such gear is much cheaper on a relative scale and much more reliable as well as MUCH more complex, so harder to repair.
They still have proprietary firmware for booting up.
You mean the guys who don't exist?
Yeah, YOU repaired such gear. 99.99% of people can't and don't. Why can't you see that? You always show a very limited view of the world from your own little corner without understanding how anyone else views it.
People make a big deal of windmill scrap. I wonder which is a greater issue, PWBs or windmills? We sell something like 2 billion cell phones each year... just cell phones! I bet the cell phones generate a lot more scrap than the share of the windmill scrap that was used to charge cell phones.
That works nicely for printers that can tolerate start/stop paper feed operation, such as inkjet printers and plotters. Laser printers need an uninterrupted paper feed (to keep the fuser from setting fire to the page when the paper stops) which is not likely to happen if the computah has to send parts of a page to the printer. Even with some buffering, any interruption in data transfer will cause a misprint simply because the paper cannot stop moving in mid page.
Ever see a laser printer that stop feeding paper so the computer can catch up? I haven't.
Which model Tek Phaser? The neighboring office had one. Long warmup time, expensive wax bricks, wax in printed page would sometime melt or crack, wax didn't stick to some types of paper, reds would fade, slow printing, etc. Otherwise, I really liked it because the colors were bright and accurate. I didn't know the Phasers could do 1200dpi. The neighbor has one of the earliest Tek versions.
However, to be fair here, we were discussing the HP LJ 5MP, which is a monochrome laser printer, not color. Color introduces a whole new set of problems, including yet another increase in required RAM. Usually, the printer manufacturers reduce capabilities in some way in order to keep costs down. For example, the Brother mfc-9840cdw color laser printer:
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prints at 2400 x 600 dpi because the base version only ships with
128MBytes of RAM. This can be increased to 640MB RAM, but the print resolution remains the same. They're probably (not sure) using some of the added RAM for rasterizing the entire page, and the rest for print buffering, font smoothing, HPGL emulation(?), and Postscript 3 processing.
Well, that's a good general statement. Add to that how it's handled if some of the processing is done in the computah (Truetype, JPEG rendering), some of the processing in the printer (font smoothing, PCL interpretation, Postscript, etc). At this time, there's quite a bit of processing happening in both the computah and the printer. However, the original problem was about trying to print todays complex documents on a 1995 vintage laser printer. The computer might be furiously computing, but the printer is still running at 1995 era memory capacity, processing speeds, and capabilities. Without sufficient printer RAM to build a bitmap of the printed page, a 24 year old printer is only going to print what was possible in 1995.
True. Each page has to be stored in printer RAM in order to print. To save on RAM, my HP Color LaserJet MFP M477fnw will only do 600x600dpi, or 38,400x600dpi in an enhanced dpi mode that I've never been able to make work. RAM is 256 MB NAND Flash and 256 MB DRAM with no options to add more RAM.
Are you sure the gears are delrin and not nylon? I'm not sure and don't have any loose gears handy to check. "HP 8640B Gears - Nylon or Delrin? DeVries says Nylon! "
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From India:
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Cast resin gears:
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HP 8640b range & peak deviation gears replacement
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HP 8640 Service: Hints & Kinks
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See item 2 and 3.
One of my HP 8640B generators on the left. A customers HP 8640B partly disassembled on the right:
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I like my gear repair method better. Carefully save the pieces of broken gear, which conveniently cracks in two pieces at the set screw hole. Glue the pieces back together. Plug the set screw holes in the gear and hub with wax. Use a large round file to enlarge the center hole in the plastic until it fits over the brass insert. Glue the parts together with epoxy and let harden. Clean out the set screw threads with a tap and you're done.
I don't care. I just followed a discussion with a happy ending. They said Delrin. But it kept me from buying one.
I mostly use R&S generators. I have a 8662A that is in its favorite state: broken. Works from 0 to 160 MHz, does not from 160 to 320, works again from 320 to 480, does not from 480.. and so on. It will take some pressure to make me open it. Or boredom. Or someone who says: "That's easy! mine had that, too..." :-)
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