Konica Minolta C308 - Cyan issue

[Kenny]

Hi guys,

we currently have a C308 with a cyan issue, the cyan haltone had gone really faded (can hardly see it). I Have replaced the cyan developing unit but after running the machine for a bit the cyan unit has turned black when i have pulled it out? when i run a print it still shows cyan on prints.

i have checked the TCR level and they are between 6.0-7.0 so they are fine. we are using genuine toner, the machine is on the latest firmware and have cleaned out the little ducts on the hopper unit (with the white plugs)

i am most likely going down the route of replacing the HV board but wanted to see if any of yous guys have any suggestions.

[robinsonad86]

Re: Konica Minolta C308 - Cyan issue

The fact that cyan dev is turning black would suggest toner isnt being added, which is strange seeing as your TCR values are well within range. Have you checked the toner bottle is turning? Have also had a similar issue caused by the small dev board that sits behind the waste box. Failing that think you could be right with HV

[SimoneCariz]

Re: Konica Minolta C308 - Cyan issue

Hi guys,

we currently have a C308 with a cyan issue, the cyan haltone had gone really faded (can hardly see it). I Have replaced the cyan developing unit but after running the machine for a bit the cyan unit has turned black when i have pulled it out? when i run a print it still shows cyan on prints.

i have checked the TCR level and they are between 6.0-7.0 so they are fine. we are using genuine toner, the machine is on the latest firmware and have cleaned out the little ducts on the hopper unit (with the white plugs)

i am most likely going down the route of replacing the HV board but wanted to see if any of yous guys have any suggestions.

Hi,
have you checked the erase lamp?
lately i find some machine where don't work or work partially and don't erase completly the drum.

[tsbservice]

Re: Konica Minolta C308 - Cyan issue

Any consumables over life? Remove drums and devs and check backside of machine for clogged toner air ports/ducts especially cyan. Check ozone filter is it full with cyan?

[REGSIS]

Re: Konica Minolta C308 - Cyan issue

Any consumables over life? Remove drums and devs and check backside of machine for clogged toner air ports/ducts especially cyan. Check ozone filter is it full with cyan?

There's no ozone filter on 8 series since charging grids are replaced by charging rollers.
In theory HV unit (or wire/connections) should be causing the problem since the reading of TCR sensor is 6-7% with no toner on magnet roller. Voltage bias C is not holding toner on magnet roller.

Check value of Vb C in State confirmation/table number!

[tsbservice]

Re: Konica Minolta C308 - Cyan issue

There's no ozone filter on 8 series since charging grids are replaced by charging rollers.
In theory HV unit (or wire/connections) should be causing the problem since the reading of TCR sensor is 6-7% with no toner on magnet roller. Voltage bias C is not holding toner on magnet roller.

Check value of Vb C in State confirmation/table number!

[Kenny]

Re: Konica Minolta C308 - Cyan issue

Hi guys,

i have just turned the machine on checked the levels

values.jpg

VDC-C is 800
VG-C is 950

[Gift]

Re: Konica Minolta C308 - Cyan issue

I don't know why but cyan devs fails the most.

Better replace the DV unit and drum as a set (in case the drum is near/end of yield). A faulty drum can lead to draining the dev, too. We also had dv drain issues with improper modified BK->COL drums...

[tsbservice]

Re: Konica Minolta C308 - Cyan issue

Hi guys,

i have just turned the machine on checked the levels

[ATTACH=CONFIG]49827[/ATTACH]

VDC-C is 800
VG-C is 950

Way off. You better replace cyan drum together with dev unit.

[REGSIS]

Re: Konica Minolta C308 - Cyan issue

Hi guys,

i have just turned the machine on checked the levels

[ATTACH=CONFIG]49827[/ATTACH]

VDC-C is 800
VG-C is 950

Cyan develpoing unit is new and if there is developer on magnet roller and just toner is missing there is no need to replace it again.

I would try with a new ( or used ) drum YMC and run TCR manual add for cyan and "image stabilization only". After stabilization check VDC-C and VG-C if they are back to normal.

After that pull out dev unit c and ckeck if magnet roller turned cyan i.e. holding cyan toner on itself.

If not I would use HV board from other machine and see if that get satisfactory result.

Again run TCR manual add for cyan to rotate dev unit (cyan toner must fill magnet roller) and "image stabilization only" to correct the values.

After you find problematic component, order and replace a new one.

[Kenny]

Re: Konica Minolta C308 - Cyan issue

Cyan develpoing unit is new and if there is developer on magnet roller and just toner is missing there is no need to replace it again.

I would try with a new ( or used ) drum YMC and run TCR manual add for cyan and "image stabilization only". After stabilization check VDC-C and VG-C if they are back to normal.

After that pull out dev unit c and ckeck if magnet roller turned cyan i.e. holding cyan toner on itself.

If not I would use HV board from other machine and see if that get satisfactory result.

Again run TCR manual add for cyan to rotate dev unit (cyan toner must fill magnet roller) and "image stabilization only" to correct the values.

After you find problematic component, order and replace a new one.

i have tried the above, but still not got it working.

here's what i have tried:

- tried a HV board from another machine it didn't change the levels and the cyan dev is still black

- tried a used dev and drums from another machine, the dev has once again turned black? i also tried a new dev and drum but still no avail.

- i have pulled out the main drive and checked if the air ports where full, they wasn't.

- checked the toners bottles are turning

- i cannot see what is over life as for some reason all the consumables have been reset the machine has only done 150k

- i have pulled out the toner hopper to see if it clogged/blocked but looks fine.

dont really know where to go from here

[femaster]

Re: Konica Minolta C308 - Cyan issue

Have you confirmed that the shutter on the bottom of the hopper assembly is opening when the dev unit is inserted?
Have you verified that the hopper is actually turning and attempting to add toner to the dev unit?

Easiest way to know for sure if it trying to add is to pull the output tray cover off from above the toner bottles, run the manual toner add for cyan, and watch the metal shaft/gears that is closest to the exit of the copier. This is the shaft that should turn when the hopper is adding toner to the cyan dev unit. See silver metal shafts in included picture. The shafts are positioned so that they are in between the toner bottles. If needed, remove the Cyan and Black toners for easier viewing.
C308 Hopper Unit.jpg

[kingarthur]

Re: Konica Minolta C308 - Cyan issue

Hi guys,

i have just turned the machine on checked the levels

[ATTACH=CONFIG]49827[/ATTACH]

VDC-C is 800
VG-C is 950

This is probably caused by one of the other colours being "over life"

[Kenny]

Re: Konica Minolta C308 - Cyan issue

Have you confirmed that the shutter on the bottom of the hopper assembly is opening when the dev unit is inserted?
Have you verified that the hopper is actually turning and attempting to add toner to the dev unit?

Easiest way to know for sure if it trying to add is to pull the output tray cover off from above the toner bottles, run the manual toner add for cyan, and watch the metal shaft/gears that is closest to the exit of the copier. This is the shaft that should turn when the hopper is adding toner to the cyan dev unit. See silver metal shafts in included picture. The shafts are positioned so that they are in between the toner bottles. If needed, remove the Cyan and Black toners for easier viewing.
[ATTACH=CONFIG]49860[/ATTACH]

i have checked the shutter and is opening when inserting the dev unit,

i have performed the manual toner add and the metal shafts do not rotate, i have checked on a working C308 in the office and those metal shafts don't move either?

[REGSIS]

Re: Konica Minolta C308 - Cyan issue

dont really know where to go from here

Huh! This is wild!
Try Front side board FSB (behind waste toner box) and Power supply board (on the left side).

Is Magnet roller turning cyan if you turn dev unit C manually?
If yes mark the white gears on the back end to check if they are turning.
There should be only one clutch for CMY (at least it is on 4 series), so that shouldn't be the problem, but just in case.

Are you running manual TCR and image stabilization + checking the voltage values after each attemp?