Randomly black image iR7105 V2

[Raoufselwaness]

hi friends
I have issue with ir7105 gives random black copy while working and if paper jam happens it starts working normally after releasing jammed paper .I have replaced the main charging unit from working m/c but this fault appears three or four time a day. i suspect the H. V. T. PCB ASSEMBLY but it takes three to four days to have new one any idea ?
NOTE the M/C is working in perfect way between the faults
attached a copy
thanks in advance

[Phil B.]

hi friends
I have issue with ir7105 gives random black copy while working and if paper jam happens it starts working normally after releasing jammed paper .I have replaced the main charging unit from working m/c but this fault appears three or four time a day. i suspect the H. V. T. PCB ASSEMBLY but it takes three to four days to have new one any idea ? NOTE the M/C is working in perfect way between the faults attached a copy thanks in advance

bias problems cause all black copy...
have you:
printed out the error logs?
cleaned all contacts on drum/belt etc?
are you using OEM toner/Drums?
the example is a copy.... what do PRINTS look like?
what is the life counts on Drum?
other than changing corona WHAT have you done?
what are the settings for the bias control items?
I take you have a service manual?

You MUST help us with INFO

before we can help you with the problem

[Raoufselwaness]

bias problems cause all black copy...
have you:
printed out the error logs?
cleaned all contacts on drum/belt etc?
are you using OEM toner/Drums?
the example is a copy.... what do PRINTS look like?
what is the life counts on Drum?
other than changing corona WHAT have you done?
what are the settings for the bias control items?
I take you have a service manual?

You MUST help us with INFO

before we can help you with the problem

thanks for your prompt replay
the sample is test #1 (print)> the fault happens during print and copy
the toner is OEM
drum life is 2.5 mil
i have cleaned all charging corona and stretched new corona wire (by the book)
all values in service mode copier>adjust according to the data on m/c door

[Canuck]

Bad laser...common on these..I've seen them print black like that, mirror images. You can order the laser diode assembly

[Raoufselwaness]

Bad laser...common on these..I've seen them print black like that, mirror images. You can order the laser diode assembly

thanks canuck;
but it not always black it my work all day fine and suddenly print this black copy with words appear like sample
and some times it print faint copy and start to print fine again ??
yesterday i checked the drum unit and DV tank assy for any short or leak it seams ok.
cleaned potential sensor too
iam waiting for laser unit to replace.
thanks again

[zoraldinho]

Turn potential control off,print test again end report back.

[dan7777]

thanks canuck;
but it not always black it my work all day fine and suddenly print this black copy with words appear like sample
and some times it print faint copy and start to print fine again ??
yesterday i checked the drum unit and DV tank assy for any short or leak it seams ok.
cleaned potential sensor too
iam waiting for laser unit to replace.
thanks again

Don't forget the drum ground. I think it may go light when you loose ground. Dark could be HVT or maybe a cracked charge connecter. When you loose all charge it would be black. I am just throwing ideas out there. All mine were replaced years ago.

[Raoufselwaness]

Turn potential control off,print test again end report back.

thanks zoraldinho;
i have already done that unfortunately the fault pops up !

[Canuck]

If it did not charge, it would be all black with no image. Laser...I've replaced a few. There actually was a bulletin from Canon. Replace the laser diode assembly

[Raoufselwaness]

Hi all
I'm so sorry not to com back and tell the results
this is because its holy week ,Easter and spring festival in Egypt.
so; i have checked every comment from your replay and asked for support from a friend working in canon dealer "paid"
he redo every thing again and finally tell me that maybe the DC controller as he knew about this but did not face it before
he send me canon Canada technical publication (attached), and they said that the problem appears only when
copy/print from deck 1 cassette 3/4 only , and never for deck 2 because noise from deck 1 cassette 3/4 assy.
i instructed the customer to work only from deck 2 and it has been 3 weeks the problem never com back.
during this week i will have another DC controller hopefully be modified.
thanks for all of you