Magenta smudges, Xerox 7845i - HELP!

[Miniman]

Hello all experts!

Expert level help desperately needed. My trusty Xerox 7845i is not feeling well...
Any idea or information where these magenta stains come from?

It seems that they only come when the paper comes from certain platforms/trays - but I’m not sure.
After that, the smudges recur but fade if I print in black and white.

Is there any magenta color spill or something somewhere?
I think the problem somehow started when I printed some heavier glossy paper (like 200 g/m2, SRA3 size) but not sure if it had anything to do with that.
Can I vacuum or clean something?
Will it help if I put in new toner cartridges and drums?

All help are welcome and needed!
BIG thank you in advance.

 

[Miniman]

I got an advice from another forum that the cause might be a ”bad magenta drum”.
Good advice.

Is magenta drum = R3?
I assume the drums are in the same order as the toner cartridges.

And, is the »belt cleaner» same as »Belt Transfer (IBT) Cleaner»?
Any special cautions how to wipe it down? Should I use air sprayer?

... any thoughts about these levels, below.

All info and thoughts about this my Xerox 7845i issue are much obliged and welcome
Thanks in advance!

 

[Miniman]

Now I have
+ replaced the IBT Cleaner with a new one
+ replaced waste tone container with a new one
+ new drum, R3
+ new toners.

This helped to get rid of the smudges.
Only small yellow markings at one side. I’m not sure if they were there before.

Tomi wrote on another forum, ”An old fuser, worn fuser rollers and thermistors cause insufficient fusing.”

Is there any way for me to somehow check if this is the problem cause? Before replacing it? How do I know if it’s time to replace the fuser assembly?
And is there other fuser assembly versions than 120 V?

All info and ideas welcome! Thanks in advance!