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HP CM1312 Printer

Discussion in 'Electronic Repair' started by [email protected], Sep 21, 2013.

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  1. Guest

    I posted about this before but it got back burnered. I ran out of black toner and the thing quit working. I was reluctant to buy a toner cartridge because I suspected something had gone wrong with the printer. I was right. The black did start to fade away of course, but one day it just wouldn't print anything at all in any color. All the sudden like.

    Recently I acquired a junk printer the same model. I was told it needs a fuser which is quite expensive. After taking it apart (violently) I can see why. Yes I animaled it a bit because I don't have all month.

    Anyway, in my opinion, not enough paper has been run through mine to think the fuser is even worn out. I never eve put toner in it.

    It was not in the best of environments for a time. A small area full of people smoking cigerettes among other things, and generally not air conditioned in the summer, and gas (gravity) heat in the winter. I suspected high voltage problems.

    If mine needs a fuser or any major mechanical thing it is getting thrown out. I see how this thing is put together and they certainly don't make it easy to take apart. I will say that it is prety nifty engineering really. I won't say impressive but not being familiar with this type of equipment I can appreciate the design.

    On one side is a board with the HV supply, they use jumper wires on the component side to make contact with spring things that conduct all the way to the toner cartridges which have the rollers built in. So far so good. That is the part I am going to get into first on mine.

    At this point I wonder what kind of voltages I should expect. Of course more than zero but how much ? Couple hundred, couple thousand ? I can't see itbeing over about 2 KV because it doesn't appear to be made for any higher.If I see 700 volts there I would have no idea if that is low or what at this point so that is one piece of information I would like.

    Unless I find that something was spilled on the board, and I lack HV which I suspect, it seems quite possible that one of the cartridges might be shorted. Of course I do not expect this to show up on an ohmmeter....

    If anyone has worked on these I would appreciate anything. If I wanted to eliminate the toners as a short, how would I go about faking the machine outto make it run with them removed ? I might have a way, almost....

    The junk machine had one toner missing. I already put the black in mine andtried it. It reads full up which brings me to another question. I wonder how it tells the level.

    From what I've gathered, printers now do not need to weigh the toner or detect the level of ink in an inkjet, they can approximate it very closely by just what has been printed. Apparently this causes a problem when one refills his own. As such they sell a replacement chip for the cartridge that supposedly fools the machine into working.

    Having thought about the matter, this could work several different ways. Ofcourse the data could be burned into the chip, but it could also be storedin the machine in NVRAM and the chip on the toner is simply a serial number. This would work just fine unless people started swapping toners. Would HP go to the trouble of doing it the harder way ? (well, more expensive by PENNIES !)

    The vendors of the replacement chips state that your printer must be working well at the time of replacement for it to work, after that you just fill the tank when the need arises.

    The question therefore is; the toner I put in from the donor machine reqds full, does that mean it's full or is the machine just assuming it is new and starting its countdown ?

    I will be tearing into the machine I want to save in the next couple days. I would like some ideas about what kind of voltages to expect and so forth.Anything help[ful is appreciated, and if I (we) get this thing running there might be some beer in it for someone....

    Thanks in advance.
  2. N_Cook

    N_Cook Guest

    toner level sensing is usually by a sort of inductive proximity
    detector, the toner (or not) changes the Q of a resonant circuit
  3. Guest

    "toner level sensing is usually by a sort of inductive proximity
    detector, the toner (or not) changes the Q of a resonant circuit "

    The chip is cheaper.

    Anyway I now found I was measuring the wrong place. I need to drag it out again and check for the HV, which I STILL don't know what should be. The difference now is I know where.

    If that proves good, I assume I would have to have a look into the fuser. Uugh, it better not be that. I don't hasve one and even if I did I would refuse, it is too much work for this unit. Five hundred new, on in pristeen condition froth with toners might fetch half that. The fuser is $190. If I stole one I would not put forth the effort to change it. (we clear on that ? lol) It would take too much time, really.

    Actually **** it for now. I only came in for a trim on my left front paw soI oculd play some guitar.
  4. Guest

    Thanks. I kinda started thinking like that. Trying to be a printer technician. I have determined that fuser is good.

    The parts unit seems to have taken on moisture, perhaps cat uriine as he said he has three cats. Toward the bottom is what I think is called the transfer plate, on his there is toner all over the place and the rollers on the cartridges have all kinds of lines in them.

    I actually got the manual for the thing, surprisingly.

    I know it has the word "store" in the URL but I got it for free. You might want to bookmark that.

    As a test I again ran the color copy mode, it actually did print but very faintly. The paper was slightly warm, I would guess from the fuser. The little bit of toner on the page was stuck well, it did not smudge.

    According to the maual there are like 13 HV power supplies. These things have come some way since I familiarized myself with the process.

    Anyway, in my current opinion, one of the HV sources is out. There is a slight possibility that the LASER is bad and only putting out a fraction of it's power but it seems to me that the HV is more likely to fail. It doesn't matter though because I have the whole HV board as well as the LASER assembly.

    Replacing either as a whole would require alot more disassembly so I would really prefer to just replace a couple of components on the HV board.

    Is there a surefire way to confirm the output of the LASER ? One reason I ask is that they don't seem to give alot of detail on these HV supplies, like how much do they put out. Towards the bottom of the board where the section is that (I think) charges the drums I see disc caps rated at 6 KV.

    At this point when I tear into it again, (hopefully after sage advice from here...) I figure I'll take a wild guess that they didn't uase 6KV caps fora 5 volt line, that it is definitely over 2 KV. Unfortunately I have no HVprobe, but I'll figure out how to measure it. I might have to go digging through my old big resistor stash.

    What would really help is a way to confirm the operation of the LASER. The other thing I would like to know, and yes I wil RTFM some more to see if itis in there, is there just one LASER and a bunch of mirrors or are there four LASERs ? It almost seems there should be four because to only use one would be an engineer's nightmare. If there are indeed four LASERs it is highly unlikely that all four of them to take a shit at once which leaves the power supplying them. Doesn't aseem to be much there, one plug with four or five wires, and a ribbon cable. I would gues the ribbon cable supplies the data in something like an LVDS format and the other plug is power. That is accesible from where I'm at, but the thing is I am going to have to comb that manual for info on the pinouts. Last time I was trying to understand whythe hell there are 13 HV supplies in there. It's starting to make some sense but I can indulge in more studies of the theory of operation (and the universe) after the thing works. I don't need the parts from it all over the place for ten years.....LOL, I have enough things like that.

    So really, confirming LASER operation, perhaps I could smear lemon juice ona sheet of paper or something like that ? BELIEVE ME I am not going to tryit without someone saying I should. I don't want to wreck those rollers and all that by sticking anything on there it won't like.
  5. Guest

    "The fuser is
    We are NOT clear on that. What I thought was the fuser panel, from what the guy said, is actually the transfer panel I think. The fuser is not all that hard to change. The transfer panel is what is smack dab in the middle of everything.
  6. Guest

    It seems to have been the LASER. I changed th HV board - nothing. then of course I forgot to rehook this little spring thing to the LASER assembly and it wouldn't work.

    Now comes the fun part, putting it all back together.

    So, on the by and by here - are these manufacturers allergic to screws ? Everything clicks together in this thing.
  7. Guest

    OK, it survived the operation. Now I have to find out how to do the registration because it is awful.

    Also I would like to hack a wireless MODEM/router to connect the thing to the house network, but one thing at a time.

    Anyone got any ideas how to set the registration on this thing or should I just start pressing buttons and/or go through the software ?
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