Faint Magenta on MX3500

[rayjeek]

Customer reported poor copy quality but upon printing out 64-01 noticed Magenta was very faint, almost considered missing but not blank but other colours ok. I replaced 1st transfer belt, CYM dev and drum units calibrated but no luck. I then replaced separation transfer clutch, removed LSU shutter for Magenta and lubricate but still had M dropped. Am now thinking of replacing the M dev unit or procees unit electrode/casing at rear of machine. Would you please help. Thanks

[tmaged]

It seems to me you're spending a lot swapping parts. Is the solid on the drum when you do 64-1 ?

[OMD-227]

Magenta is normally the first color to go missing on those machines.

Most of the time, you dont need to do anything else but 'force' the machine back into correct colors by running the following first. Always do this first, before replacing anything, especially if the maintenance & consumable item counters are not due.

Clean the ID sensor unit very well. Take the magenta toner cartridge out and shake very well. Put it back in, run 44-06 & 44-26 to force process control & halftone correction. You should notice that it will take much longer than normal, as running these steps in sim will force the machine to detect that the toner levels in the dev mix are not right, therefore adding toner & running patches to correct toner conentration. If you get HV errors on the display when doing this, you either have a problem with the HVT board, or a cable is disconnected for that color channel on the HVR pwb (on the main drive unit). If you dont get any HV errors on the display running 44-06 & 44-26 and the procedure doesnt take long/same output quality, run 63-08 & 67-28, then run 44-06, 44-26, 46-24 & 67-24 after the restart. That should bring it back up to normal.
If the magenta is still bad after all that, replace the magenta dev (with the magenta toner removed), run dev reset procedure, restart, run 44-27, restart, then reinstall magenta dev. Run full color calibration after that. I'd be very surprised if the problem is still there after this.

I really doubt the problem is the process electrode & case or the dev unit at fault. These cause definite trouble codes, dev overtoning very severely and various other issues. Your machine is working, without trouble codes, so its more of a process calibration level adjustment.

It wouldnt have been the clutch, as this drives all 3 color transfer rollers down at the same time. You'd get either 3 light colors or L4-06 problems if there was a clutch or main drive unit issue.

[rayjeek]

Will follow all the steps and let you know

[OMD-227]

Info sent.

[rayjeek]

This is just an update to announce that the problem was with the primary transfer belt unit.

Wazza's response QUOTE
If a different primary belt solved the problem, that tells me that the magenta transfer roller was not dropping down far enough onto the magenta drum for correct transfer of the image.
Causes of this could be a missing tension spring on either front or rear frame of the belt unit for the magenta transfer roller, a missing charge spring not making contact with the conductive black plastic hook on the end of the roller, or maybe an over-tight transfer belt cam assembly, causing a poor transfer roller drop.

Hey, in the end, I'm just glad its working.

Keep an eye on this one though.
UNQUOTE