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asked Jan 21, 2012 at 9:09am
Sharp Sharp MX B401

sharp mfp mx-b401 error code c4-16

im am trying to troubleshoot a Sharp mfp mxb401 with an error code c4-16. all i know is its a high heater temp error. can i get some advice on what physical parts might i look and troubleshoot first. thank you.
The fuser rollers are getting too hot. Open the right hand door, the fuser is the hot bit, it usually has warning signs and yellow decals on it.
Take it out, probably two blue screws then a grey lever at each end of the fuser. Check that the rollers will turn (use the drive gear on the side, NOT the rollers themselves as they are easily damaged) If they will not turn they may have melted and stuck together in which case you need to replace them which is tricky but possible with care.
If they do turn you may have crap on a thermistor which renders it less sensitive and makes it call for more heat than it should and eventually melts the pressure roller (the rubber one) if the thermostat doesn't work in time.
The thermistors actually touch the rollers and you can often see a track on the roller where the thermistor runs. If you can see these tracks, use them to locate the thermistors, you may need to remove external covers. When found remove the single retaining screw, release some loom from it's clips and carefully withdraw the thermistor. Pay close attention to which way up it is, they are keyed but it's best to get it right first time. You may need to disconnect the leads but don't if you can manage, they are a tight connection and if you pull the lead out of the connector you'll have to buy a new thermistor or loom. You may find crud on the face of the thermistor, clean it off carefully with Isoprop or meths and refit. Repeat on others. Refit the fuser and turn on the copier.
Fuser errors need to be reset. Wait until the copy screen and error code appear. Press 'P' '*' 'C' '*' in sequence to get into the service menu, then key in '12' on the keypad. The screen will say something like "Reset fuser temp error", then press the'Start' key or 'Execute' if it appears on the screen. Press 'CA' to exit. If the error persists do P*C* again and try 13, if that doesn't work try 14. I'm doing this from memory and can't remember which one it is, sorry, but you won't do any harm by keying in any of those.
If you get a subsequent warning that the fuser is not reaching temperature then a thermostat may have popped due to the overheat. Believe it or not you can reset it by removing it and and smacking it on a firm surface. There are two of them located on the metal frame above the hot roller(the hard Teflon coated one thru which the heater lamps run), they are lozenge shaped about 10mm in length and each is secured by two screws. Carefully remove one spade connector from each thermostat and do a continuity check, there should be no resistance. If there is an open circuit then the thermostat has popped and needs to be reset in the manner suggested above.
Good luck.
by chrisbov on Feb 24, 2012 at 2:47pm Add comment