Page 1 of 5 12345 LastLast
Results 1 to 10 of 41
  1. #1
    Junior Member
    Join Date
    Nov 2020
    Location
    mycity, st
    Posts
    9
    Rep Power
    0

    Bizhub C308 Power Supply Humming Noise - Fuser

    Hello, I own a KM Bizhub C308. The unit was built in 2018. From what I can tell, the unit performs perfectly. However, the power supply exhibits the "humming" described by other folks on similar Bizhub printers. I've tested the electronics using clamp meters, a DMM, and a digital scope. The power is being drawn by the fuser power circuit. This section of the PSU has a triac and a series inductor coil to power the fuser heaters. The individual heater lamps are approximately 1.4 ohm and 2.5 ohm. I don't have access to any specifications, so I'm hoping they are testing okay. At those impedance levels, I see why the current is drawing so hard. I see a spike every 5 seconds to about 13A. Without the inductor, the initial current would probably be around 80A! I can understand the point of keeping the fuser hot while in ready mode, but I don't see the point of a triac if we're simply turning the fuser on/off. It's a solid state switch, but it can also throttle the heat and avoid the need to turn on/off. It would likely be easier on the fuser too.

    The current draw seems excessive. The lights dim and the unit makes a disruptive humming sound that is causing problems for our users.

    I have two questions. 1.) is this normal for a c308 to cycle the fuser on/off like this while in the "ready" state? 2.) what can be done to mitigate the large rush of current to the printer? Do later firmware mitigate this situation by throttling the triac a little to avoid the current spike?
    Last edited by engr; 11-29-2020 at 05:11 AM.

  2. #2
    RTFM!! 2,500+ Posts allan's Avatar
    Join Date
    Apr 2010
    Location
    Centurion
    Posts
    4,294
    Rep Power
    93

    Re: Bizhub C308 Power Supply Humming Noise - Fuser

    Try changing the fuser temp control mode in service. Think there are like 4 different modes.
    Whatever

  3. #3
    RTFM!! 2,500+ Posts allan's Avatar
    Join Date
    Apr 2010
    Location
    Centurion
    Posts
    4,294
    Rep Power
    93

    Re: Bizhub C308 Power Supply Humming Noise - Fuser

    308temp.jpg

    Ok so not modes but phase control levels.
    Bad image but look for it in the manual.
    Describes the issue you have, its noise thrown back from the phase control that can be changed.
    Depends i guess if you are on 50 or 60Hz.
    Whatever

  4. #4
    Junior Member
    Join Date
    Nov 2020
    Location
    mycity, st
    Posts
    9
    Rep Power
    0

    Re: Bizhub C308 Power Supply Humming Noise - Fuser

    Thank you @allan for your response. I cannot really read the image from the manual you posted and I searched the manuals I have access to for the heater modes, but can't find anything. I know exactly what you're talking about and I did try changing these in service mode. I didn't notice any difference, but I didn't really understand what each mode did. It would sure be nice if KM would explain each setting in their software.

    Being on 60 hz, I suppose I my setting might be different, but the machine has always been configured for 60 hz. The noise is only part of the problem. I can probably quiet the coil by gluing the windings. More of the problem is the lights near the office dim when the printer pulls heat (every 5 sec).

    Quote Originally Posted by allan View Post
    308temp.jpg

    Ok so not modes but phase control levels.
    Bad image but look for it in the manual.
    Describes the issue you have, its noise thrown back from the phase control that can be changed.
    Depends i guess if you are on 50 or 60Hz.

  5. #5
    RTFM!! 2,500+ Posts allan's Avatar
    Join Date
    Apr 2010
    Location
    Centurion
    Posts
    4,294
    Rep Power
    93

    Re: Bizhub C308 Power Supply Humming Noise - Fuser

    Quote Originally Posted by engr View Post
    Thank you @allan for your response. I cannot really read the image from the manual you posted and I searched the manuals I have access to for the heater modes, but can't find anything. I know exactly what you're talking about and I did try changing these in service mode. I didn't notice any difference, but I didn't really understand what each mode did. It would sure be nice if KM would explain each setting in their software.

    Being on 60 hz, I suppose I my setting might be different, but the machine has always been configured for 60 hz. The noise is only part of the problem. I can probably quiet the coil by gluing the windings. More of the problem is the lights near the office dim when the printer pulls heat (every 5 sec).
    Florescent lights?
    Whatever

  6. #6
    Service Manager 2,500+ Posts tsbservice's Avatar
    Join Date
    May 2007
    Posts
    3,293
    Rep Power
    149

    Re: Bizhub C308 Power Supply Humming Noise - Fuser

    When the fluorescent light flickers you should go down the levels and when there is a noise at power source system turn up the level.
    It's in service mode --> Machine --> Heater control level
    A tree is known by its fruit, a man by his deeds. A good deed is never lost, he who sows courtesy, reaps friendship, and he who plants kindness gathers love.

    Blessed are they who can laugh at themselves, for they shall never cease to be amused.

  7. #7
    Master Of The Obvious 10,000+ Posts
    Bizhub C308 Power Supply Humming Noise - Fuser

    blackcat4866's Avatar
    Join Date
    Jul 2007
    Location
    Lapeer, Michigan
    Posts
    18,843
    Rep Power
    336

    Re: Bizhub C308 Power Supply Humming Noise - Fuser

    It's entirely normal for fuser heaters to turn On in pulses at 60Hz intervals (in the US).

    The way I understand the theory, when the AC voltage passes through the zero volt axis (or zero-cross) the heater is pulsed on so that it draws the minimum amount of watts. Some machines (specifically Kyocera, maybe others) can identify variations in the frequency. The idea is that the heater control circuitry must be able to anticipate the next zero-cross to pulse on the heater. If the zero-cross does not happen when anticipated the MFP can draw significantly more watts. Kyoceras will trigger a zero-cross error ... meaning that the AC frequency varied too much.

    All that being said, humming has been an ongoing issue with certain models. There was a Canon with particularly noisy power supplies. When I ordered a replacement sometimes the power supply was quieter, sometimes louder. Sometimes putting that same noisy power supply in a different machine made it quieter. The amount of hum never affected its ability to power the machine.

    If you can live with the noise, I recommend doing nothing.
    =^..^=
    If you'd like a serious answer to your request:
    1) demonstrate that you've read the manual
    2) demonstrate that you made some attempt to fix it.
    3) if you're going to ask about jams include the jam code.
    4) if you're going to ask about an error code include the error code.
    5) You are the person onsite. Only you can make observations.

    blackcat: Master Of The Obvious =^..^=

  8. #8
    Service Manager 1,000+ Posts
    Bizhub C308 Power Supply Humming Noise - Fuser

    BillyCarpenter's Avatar
    Join Date
    Aug 2020
    Location
    Long Beach, Mississippi
    Posts
    2,315
    Rep Power
    84

    Re: Bizhub C308 Power Supply Humming Noise - Fuser

    Quote Originally Posted by blackcat4866 View Post
    It's entirely normal for fuser heaters to turn On in pulses at 60Hz intervals (in the US).

    The way I understand the theory, when the AC voltage passes through the zero volt axis (or zero-cross) the heater is pulsed on so that it draws the minimum amount of watts. Some machines (specifically Kyocera, maybe others) can identify variations in the frequency. The idea is that the heater control circuitry must be able to anticipate the next zero-cross to pulse on the heater. If the zero-cross does not happen when anticipated the MFP can draw significantly more watts. Kyoceras will trigger a zero-cross error ... meaning that the AC frequency varied too much.

    All that being said, humming has been an ongoing issue with certain models. There was a Canon with particularly noisy power supplies. When I ordered a replacement sometimes the power supply was quieter, sometimes louder. Sometimes putting that same noisy power supply in a different machine made it quieter. The amount of hum never affected its ability to power the machine.

    If you can live with the noise, I recommend doing nothing.
    =^..^=
    That's interesting but I don't understand why 60hz crossing the 0-threshold has anything to do with anything. In the USA most things run on 120vac at 60hz. So, the Ac sine wave goes up +60vac, goes down -60vac and that's equals 120vac. And it does that 60 times per second and that = 60hz.

  9. #9
    Master Of The Obvious 10,000+ Posts
    Bizhub C308 Power Supply Humming Noise - Fuser

    blackcat4866's Avatar
    Join Date
    Jul 2007
    Location
    Lapeer, Michigan
    Posts
    18,843
    Rep Power
    336

    Re: Bizhub C308 Power Supply Humming Noise - Fuser

    Quote Originally Posted by BillyCarpenter View Post
    That's interesting but I don't understand why 60hz crossing the 0-threshold has anything to do with anything. In the USA most things run on 120vac at 60hz. So, the Ac sine wave goes up +60vac, goes down -60vac and that's equals 120vac. And it does that 60 times per second and that = 60hz.
    Alright, try this:
    V=IR. When V=~0 momentary, 0/R=I or ~0 amps


    P=IV. When I=~0 and V=~0, then P=~0 watts momentary. In practice it's never 0 watts, but you get the idea.
    If you'd like a serious answer to your request:
    1) demonstrate that you've read the manual
    2) demonstrate that you made some attempt to fix it.
    3) if you're going to ask about jams include the jam code.
    4) if you're going to ask about an error code include the error code.
    5) You are the person onsite. Only you can make observations.

    blackcat: Master Of The Obvious =^..^=

  10. #10
    Service Manager 1,000+ Posts
    Bizhub C308 Power Supply Humming Noise - Fuser

    skynet's Avatar
    Join Date
    Apr 2009
    Location
    127.0.0.1
    Posts
    1,836
    Rep Power
    100

    Re: Bizhub C308 Power Supply Humming Noise - Fuser

    Quote Originally Posted by BillyCarpenter View Post
    So, the Ac sine wave goes up +60vac, goes down -60vac and that's equals 120vac. And it does that 60 times per second and that = 60hz.
    Not quite, it rises to +120volts and decends to -120volts
    When you think you have made a procedure idiot proof your company employs a better idiot.

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Get the Android App
click or scan for the Copytechnet Mobile App

-= -= -= -= -=


IDrive Remote Backup

Lunarpages Internet Solutions

Advertise on Copytechnet

Your Link Here