CP3505dn only printing black on bottom third of page

[NapalmNick]

Hello,

recently had to replace the usual left cartridge locking device and right cartridge slide.

Everything back up and running but the printer is only printing black (it seems) on the bottom third of each piece of A4 paper.

Have tried:

1. Stripping it down again to check MDA and work done on locking mechanisms correct including toner cam mountings etc - no problems obvious - note no printer errors are shown.

2. 3 calibrations

3. Toner change (all HP originals)

4. NV reset and Engine check

5. Various test pages all of which seem to be missing the black on the top two thirds.

I'm flummoxed, common sense implies the cartridge slide work has caused the problem but I cant seem to resolve it in that area so I am hoping the description of only the lower third of a page being printed black raises some ideas.

Thanks in advance.

bottom third printing black

[NapalmNick · Accepted solution]

As suspected....

After two weeks of leaving the printer alone after it drove me mad I stripped it a third time today and noticed that when you set the MDA up before re-insertion the black toner cog is on the edge of wanting to spring-off the needed reset position . Whilst trying to fit the MDA again today I noticed it only takes a jolt to cause the cog to spin a little and be misaligned. Finally overcoming this I got it to go on without that little cog misaligning. Gargh but its sorted now.