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[maggoolee2525]

after painstakingly going thru putting my 9400 back into working condition....run into a snag......now its BLANK PRINTS,,,,,,even from Demo print.....let alone scan and print...
here are the items i carried out :
1.Changed charger blocks...in fact when main charge unit placed in another machine it printed fine
2.changed developer unit...it worked fine on the other model
3.changed transfer the same result...just Blank
4,changed main PBA from the other unit ...still Blank!!!

should i try the controller unit .......How about some help ...its driving me nuts!!

[kh_design]

my first thought is;
during re-build some missing ground or wire connection to the printhead or zener or drum or developing unit or charger or transfer. Missing drum or developing unit ground, charger wire, transfer wire, some connection like this is a missed re-connection during re-build or faulty short connection.

Do you see toner image on the drum but no transfer of image to paper? To see this the cover will need to be off (the room ambient light should be dim) and cleaning blade relaxed backed from the drum while doing a test print. If image is on the drum but not transferring to paper then it might be a transfer issue. If no image on the drum then it might be charger or developing unit or zener or printhead issue.

Perhaps during re-build the clearance distance is incorrect from the developing unit or printhead or charger or zener to the drum, printhead was not lowered into place correctly, or missed spring or block was not re-installed or re-installed incorrectly during re-build.

Last edited by kh_design on Mon Jan 22, 2018 9:41 pm; edited 1 time in total

[maggoolee2525]

thanks Kh for that fast reply u have always been my GURU!.....when u mentioned relaxed blade to drum do u mean remove it completely from the cleaning unit or just remove the springs to the cleaning unit....
As for the short/no current ..... can u guide me on a step by step basis with me using a Sanwa multimeter on DC voltage ......i would appreciate it

[kh_design]

Perhaps relaxing the cleaning blade from the drum is not the best way to see the drum image, perhaps removing paper guide plate part#2912.350 will give you a narrow view of the drum after it passes the developer yet before the drum passes transfer and cleaning blade.

The point is, to diagnose if there is no toner image on the drum, which would then possibly be a; drum, charger, printhead, or developing issue. If you can see a toner image on the drum but the image does not transfer to the paper then it is possibly a transfer issue (hoping perhaps a transfer issue, this might be easier to solve).

I don't have a step by step basis guide for checking the wire and ground connections to all of the assemblies, just make sure all of the wire and ground connections have been properly reconnected during re-build, maybe one was missed. This is where I get back to the drum image, if you can see a toner image on the drum or not, this will help narrow-down where the issue is.

[maggoolee2525]

KH,......thanks ....here's a new problem thts putting me in a stressed situation:had this 9400 II running fine until i decided to change developer and main charge units becos of elongated grid wire.....then appeared abt.10 inches aprt from excellent print overall.. horizontal streaks with no print and traces of developer
sit on it ...it has left me bewildered ...i chked all the grd wire ,changed the copper drum ground ,insulated the dveloper unit from body,changed the HVPBA and main board ...but still cant get to the issue of those streaks...pls help