Bizhub c308 no Black

[dragonman]

Now feeling utterly frustrated. We lost the k image on the above machine and we have replaced the k drum and dev and hv board still no black. Each time I add a dev tank it empties the dev out bit by bit by dragging it to the drum and recycling it through the t belt. I've tested the 24v lines from the MFP and all is good checked continuity on the dev bias and drum charge.

Now running out of ideas. Has anyone any good suggestions?

[Synthohol]

Re: Bizhub c308 no Black

Are you getting transfer to the belt at all?
Internal test pages are blank?
Not for nothing, in the US konica has a 3 year bumper to bumper warranty.
Maybe get them involved?

[dragonman]

Re: Bizhub c308 no Black

Are you getting transfer to the belt at all?
Internal test pages are blank?
Not for nothing, in the US konica has a 3 year bumper to bumper warranty.
Maybe get them involved?

The only thing I'm getting is random dev transfer to the drum and belt but no toner image. If you print the meter readings it come out completely blank

[Synthohol]

Re: Bizhub c308 no Black

is the drum turning? is the connector from dv unit secured in the FSB? when you turn the dv do you get a good brush?

[blackcat4866]

Re: Bizhub c308 no Black

Recently I had a C658 that had no yellow and magenta. When I changed the developing units, the machine sucked the new units dry of toner in less than 10 seconds. I ended up changing the HVT along with another four developing units. =^..^=

[copier tech]

Re: Bizhub c308 no Black

So after you first replace the K image unit & dv the machine will print OK?
How long before all the dev is pulled out?

Firmware often gets dismissed however it can surprisingly rectify a number of weird issues like this.

[REGSIS]

Re: Bizhub c308 no Black

is the drum turning? is the connector from dv unit secured in the FSB? when you turn the dv do you get a good brush?

Drum is turning otherwise developer couldn't be depleted.
If connector is loose or not connected error would appear on screen.

@dragonman
When you replaced a new dev unit K what was the printout like. What's the trc state for black.
Any error after stabilization.

[dragonman]

Re: Bizhub c308 no Black

Drum is turning otherwise developer couldn't be depleted.
If connector is loose or not connected error would appear on screen.

@dragonman
When you replaced a new dev unit K what was the printout like. What's the trc state for black.
Any error after stabilization.

When you replace the dev and print out the birdie test page all registration is out and you just get a smear of black across the page. TCR is reading 6.7. No errors except for the oil can in stabilisation. If you look at the two attachments one is the copy page and the second a voltage readout does this help?

[REGSIS]

Re: Bizhub c308 no Black

Your first image have some black (minimum). Next few images and black is completely gone.
Am I right.

Your developer is not depleted. Your black dev unit is not rotating.
On the back of the machine remove right and left covers and right rear cover. Unscrew all M3 screws, remove 3 connectors and open PWB box. Remove dev motor and check solenoid behind it. It's stuck.
Either replace the sponge with piece of cardboard cca 1mm thickness, or replace the whole solenoid.

I had exactly the same problem on c224e.

After turning on the machine stabilization should run automatically and colors will be aligned.

[dragonman]

Re: Bizhub c308 no Black

Your first image have some black (minimum). Next few images and black is completely gone.
Am I right.

Your developer is not depleted. Your black dev unit is not rotating.
On the back of the machine remove right and left covers and right rear cover. Unscrew all M3 screws, remove 3 connectors and open PWB box. Remove dev motor and check solenoid behind it. It's stuck.
Either replace the sponge with piece of cardboard cca 1mm thickness, or replace the whole solenoid.

I had exactly the same problem on c224e.

After turning on the machine stabilization should run automatically and colors will be aligned.

thanks for the reply. I have checked the dev solenoid as once I'd replaced the hv board I left the back cage loose and I could quite clearly see the solenoid activating and the gears rotating.

[REGSIS]

Re: Bizhub c308 no Black

thanks for the reply. I have checked the dev solenoid as once I'd replaced the hv board I left the back cage loose and I could quite clearly see the solenoid activating and the gears rotating.

I'm not sure if you can see clearly like that if it's working properly!
I allways take out every solenoid and check manually. press the anchor down; if it's not lift back imediately then it's not working properly. Sometimes sponge got thiner and not visibly distorted thus making it working improperly.

But before checking the solenoid pull out dev unit and mark the white gears on the back of the dev unit.
Mark at least 2 gears then put unit back and start the machine. Make a sample print and pull out unit again and check if markings moved from initial position.

If they are still at the same place then your dev unit is not turning hence no black image.

What about old dev unit(s), was the magnet roller empty/half empty or brush looked normal?

Check the manual there's solenoid, clutch, gear, and transport motor (not the dev motor) which drives the black dev unit.
Maybe the gear or gear shaft is broken that you cannot see from outside while machine is running.

My bet is on solenoid since I had exactly the same problem.