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Easy 4 U

Discussion in 'A+' started by Peter, Nov 13, 2004.

  1. Peter

    Peter Byte Poster

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    This looks easy and should be easy but the only info I can find is that the thermal fuse is for the psu.

    which lazer printer componant protects the fuser from overheating

    a thermal fuse
    b primary corona
    c controller
    d transfere corona

    I would have said A but after reading up on it I think it is for the psu.
     
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  2. Phoenix
    Honorary Member

    Phoenix 53656e696f7220 4d6f64

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    wouldnt the controller handle info on hardware statistics and slow printing to accomodate,
    cant say i ever bothered to ask
     
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  3. nugget
    Honorary Member

    nugget Junior toady

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    I would also agree with C as it should do what it says, control stuff.:rolleyes:
     
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  4. AJ

    AJ Administrator Administrator

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    I have it on very good authority that the actual answer is a thermister. My boss used to service the things.
     
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  5. Jakamoko
    Honorary Member

    Jakamoko On the move again ...

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    ...short for thermo-resistor, and therefore indicating A as the correct answer ?
     
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  6. AJ

    AJ Administrator Administrator

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    You asking me, i only stick toner in the bloody things and expect then to go after that [​IMG]
     
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  7. Peter

    Peter Byte Poster

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    Cheers for that, After you told me the answer I done more research and now have found info on it. (Thermal Fuse it is)
     
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  8. Jakamoko
    Honorary Member

    Jakamoko On the move again ...

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    That is what we try to do to help - hence, no point just answering questions straight off. Nice work, Peter :D
     
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  9. MrNice

    MrNice Kilobyte Poster

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    Sorry I never read this sooner,
    The fuser temperature is controlled by THERMISTORS which regulate the heat on the roller, if the heat increases or decreases to much the THERMAL FUSE will blow cutting the machine out. The Thermistor is safety net 1, and usually throws up an error code but if it fails the THERMAL FUSE will pop acting as safety net 2. The answer is 1000% Thermal fuse :D
     
  10. AJ

    AJ Administrator Administrator

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    Hmm picking hairs here but if the first line of defence is the thermister then that surely is the answer. If that controls the temperature of the fuser unit then .........................


    not worth arguing over, and as I haven't taken the A+ I shall bow to other people better knowledge in this area.
     
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  11. MrNice

    MrNice Kilobyte Poster

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    Yeah AJ I fully agree with you and on any specialist course that would be the answer but of the options listed, Thermal fuse is the only possible, now if Thermistor was listed it would be an interesting one. :D
     
  12. Peter

    Peter Byte Poster

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    T:biggrin hanks for that guys
     
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  13. AJ

    AJ Administrator Administrator

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    Nice one Mr. Nice.

    The main thing here is that we have all learnt from this question and the answer has been found.

    much better than just giving the answer out I'm sure you wil agree [​IMG]
     
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  14. Jakamoko
    Honorary Member

    Jakamoko On the move again ...

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    I suppose someone could have opened a window near the printer...:rolleyes:
     
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  15. AJ

    AJ Administrator Administrator

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    So that how you pass an A+ exam, nothing to do with computers and the like just open a window.

    < note to self, sack the techs and get a window company in, much cheaper in the long run>




    lololololololol
     
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  16. Peter

    Peter Byte Poster

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    I have just found info that states the thermal fuse is in case the low voltage power suply overheats.

    Now I am con(fused):rolleyes:
     
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  17. Peter

    Peter Byte Poster

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    I found this does this mean it is the controler :rolleyes:

    The other source of confusion is that people tend to think of 110V (or 220V) AC as high voltage rather than low voltage. So if it does occur to them that a power supply may be causing a fuser error, their natural impulse is to replace the high voltage power supply. But in a laser printer, the high voltage power supply is only used to charge up the toner cartridge and transfer roller. These voltages are internally generated by the power supply. The voltage for the fuser, on the other hand, is not internally generated--it’s just the AC line voltage, routed through the printer. And it is always routed throughthe low voltage power supply, so that would be the one to replace for a fuser error.
    You might wonder how the low voltage power supply can cause a fuser error if the printer is just routing an external voltage through the power supply. The answer is that the AC line voltage is not applied to the fuser at all times. If it were, the heating element in the fuser would just get hotter and hotter until it burned out (or started a fire!). The low voltage power supply contains a switching circuit that applies the voltage to the fuser only as needed to maintain a temperature hot enough to fuse toner to paper, but not so hot as to scorch the paper or start a fire. It is this switching circuit that goes bad.

    To sum up, if you get a 50.x error in an HP LaserJet 8100 or 8150, the fuser is still the most likely cause. But if the fuser passes inspection, test the low voltage power supply, with the DC controller the last thing to look at
     
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  18. MrNice

    MrNice Kilobyte Poster

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    Dude,

    I do this for a living, the answer to your question is thermal fuse, The sole purpose of this is to stop the fire you are talking about, when the Thermistors log a temperature which is above the maximum tolerance the Thermal fuse "pops" disabling the machine. The Thermistor itself will normally cut out the machine before this, very common when people use the wrong type of acetate in the machine and it jams the fuser. :D
     
  19. MrNice

    MrNice Kilobyte Poster

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    In a fuser there is an electrical circuit where the current travels from the PSU through the heating lamps (inside the hot roller) and then through the Thermal fuse and back to the controller board. These Thermal fuses have a higher heat tolerance than the thermistors which normally contact the hot roller, they report back to the controller and regulate the temperature. If you have an iffy controller PCB this may fail and the fuser gets real hot for instance, the THERMAL FUSE heats up then pops thus breaking the circuit and cutting out the current and therefore heat source to the fuser. If the thermal fuse was on the PSU it would kill the machine dead. As it's on the fuser it only kills that part.
    You can reset a thermal fuse by throwing it against a wall but that's a different story. In a very high volume (75ppm+)machine the thermistors are now also sitting off the roller also to minimise wear.
     
  20. AJ

    AJ Administrator Administrator

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    and you do this for a living :eek: :ohmy :eek:
     
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