C-3906 Pro 1100

[Toxic]

Another update...
Few days ago i replaced new th4 sensor, same result,periodically c-3906,maybe little less more occurence than before but can not be sure about that.
Removed back cover, conected voltmeter and current meter on lower fuser lamp L3 and observe while printing.
Everything looks ok, lamp getting about 230v and draw about 1.4A, i was assuming some wiring or conection to lamp is lossing in some moment but that is ok.
This also should exclude thermostats, connector, lamp, lamp wiring,...as a culprit.
In continuous print L3 have about 50 seconds ON and 7 seconds OFF working cycle.
One time i manage to catch moment before C-3906 , L3 was continuously working for over 120 seconds before get coded.
At the end my suspicion is more abot PRCB than some hardware problem in fusing unit, AC board...
I will let it go for now , 3906 comes once over 1-2 days so it is not so much hassle to reset.

[allan]

Is it possible to take the fuser to another machine?

[Toxic]

Good idea and i would try that but dont have another machine near.

[tulintron]

Another update...
Few days ago i replaced new th4 sensor, same result,periodically c-3906,maybe little less more occurence than before but can not be sure about that.
Removed back cover, conected voltmeter and current meter on lower fuser lamp L3 and observe while printing.
Everything looks ok, lamp getting about 230v and draw about 1.4A, i was assuming some wiring or conection to lamp is lossing in some moment but that is ok.
This also should exclude thermostats, connector, lamp, lamp wiring,...as a culprit.
In continuous print L3 have about 50 seconds ON and 7 seconds OFF working cycle.
One time i manage to catch moment before C-3906 , L3 was continuously working for over 120 seconds before get coded.
At the end my suspicion is more abot PRCB than some hardware problem in fusing unit, AC board...
I will let it go for now , 3906 comes once over 1-2 days so it is not so much hassle to reset.

If it overheats, the lamp is ok.

TH4 sensor ok.


PRCB receives signal from TH4 and reports error when it occurs. PRCB ok.


CN213 from PRCB sends TH4 signal to ACDB to turn off L3.


I would look the other way. ACDB

[tulintron]

Someone doesn't turn off L3 when they should. But the order to turn off comes